scispace - formally typeset
Search or ask a question

Showing papers in "Journal of the National Cancer Institute in 1992"


Journal ArticleDOI
TL;DR: Microvessel density in the area of the most intense neovascularization in invasive breast carcinoma is an independent and highly significant prognostic indicator for overall and relapse-free survival in patients with early-stage breast carcinom (I or II by International Union Against Cancer criteria).
Abstract: BACKGROUND Axillary lymph node status has been the most important prognostic factor in operable breast carcinoma, but it does not fully account for the varied disease outcome. More accurate prognostic indicators would help in selection of patients at high risk for disease recurrence and death who are candidates for systemic adjuvant therapy. Our recent findings indicated that microvessel density (count or grade) in invasive breast carcinoma (a measure of tumor angiogenesis) is associated with metastasis and thus may be a prognostic indicator. PURPOSE This study was designed to further define the relationship of microvessel density with overall and relapse-free survival and with other reported prognostic indicators in breast carcinoma. METHODS In a prospective, blinded study of 165 consecutive patients, the microvessels within primary invasive breast carcinoma were highlighted by immunocytochemical staining to detect factor VIII-related antigen. Using light microscopy, we counted microvessels per 200x field in the most active areas of neovascularization and graded microvessel density. These findings were correlated, by univariate and multivariate analyses, with overall and relapse-free survival, axillary node status, and other prognostic indicators (median follow-up, 51 months). RESULTS There was a highly significant (P < or = .001) association of microvessel density with overall survival and relapse-free survival in all patients, including node-negative and node-positive subsets. All patients with breast carcinomas having more than 100 microvessels per 200x field experienced tumor recurrence within 33 months of diagnosis, compared with less than 5% of the patients with breast carcinoma having 33 or fewer microvessels per 200x field. Moreover, microvessel density was the only statistically significant predictor of overall survival among node-negative women (P < .001). Only microvessel density (P < .001) and histologic grade (P = .04) showed statistically significant correlations with relapse-free survival in the node-negative subset. CONCLUSIONS Microvessel density in the area of the most intense neovascularization in invasive breast carcinoma is an independent and highly significant prognostic indicator for overall and relapse-free survival in patients with early-stage breast carcinoma (I or II by International Union Against Cancer criteria). IMPLICATIONS Such an indicator would be useful in selection of those node-negative patients with breast carcinoma who are at high risk for having occult metastasis at presentation. These patients could then be given systemic adjuvant therapy.

1,846 citations


Journal ArticleDOI
TL;DR: Screening sigmoidoscopy can substantially reduce mortality from cancers of the rectum and distal colon, and neither fecal occult blood testing nor digital rectal examination was associated with a reduction in colorectal cancer mortality.
Abstract: Background Sigmoidoscopy may reduce colorectal cancer mortality by identifying both cancers and precursor lesions (including polyps) for treatment; however, evidence regarding the efficacy of this technique as a screening procedure is extremely limited. Purpose In the absence of data from randomized controlled trials, we performed a retrospective case-control study to determine if sigmoidoscopy screening is associated with a reduction in colorectal cancer mortality. Methods The medical records of 66 members of the Greater Marshfield Community Health Plan (GMCHP) who died of large-bowel cancer from 1979 to 1988 were reviewed for history of screening for colorectal cancer (case subjects). For comparison, the records of 196 GMCHP members of similar gender, age, and enrollment duration were randomly selected for review (control subjects). Results History of screening sigmoidoscopy was much less common among case subjects (10%) than among control subjects (30%). Risk for death from colorectal cancer was reduced among individuals having had a single examination by screening sigmoidoscopy (odds ratio = 0.21; 95% confidence interval = 0.08-0.52), compared with the risk for those who never had one. The reduction in risk appeared to be limited to tumors in the rectum and distal colon. Neither fecal occult blood testing nor digital rectal examination was associated with a reduction in colorectal cancer mortality. Conclusions These results suggest that screening sigmoidoscopy can substantially reduce mortality from cancers of the rectum and distal colon.

891 citations


Journal ArticleDOI
TL;DR: Immunohistochemically detected p53 protein accumulation was an independent marker of shortened survival and was seen more often in familial than in sporadic carcinomas, suggesting a correlation between p53protein accumulation and p53 gene mutation.
Abstract: Background Mutations of the tumor suppressor gene p53 have been identified in breast cancer cell lines, and some breast carcinomas are detectable by immunohistochemical assay because of p53 protein accumulation. Purpose This study was designed to determine whether p53 protein accumulation in breast cancers correlates with p53 gene mutation, with survival, and with five pathobiologic factors associated with prognosis. Methods IgG1 monoclonal antibody to human p53 protein (PAb 1801) and immunohistochemical methods were used to detect p53 protein accumulation in archival formalin-fixed, paraffin-embedded, randomly selected carcinomas. We studied 295 invasive ductal carcinomas from the Massachusetts General Hospital; 151 were determined to be sporadic (not hereditary). We also studied 97 invasive ductal carcinomas--21 sporadic and 76 familial (hereditary)--from Creighton University. In addition, we examined 31 archival in situ carcinomas, 15 snap-frozen invasive ductal carcinomas, primary cell cultures from three benign breast tissue samples, and breast carcinoma cell lines MDA-MB-231 and MDA-MB-468. Results Nuclear p53 protein was observed in 16% of the 31 in situ carcinomas, 22% of the 172 sporadic carcinomas, 34% of the 50 tumors from patients with familial breast cancer, 52% of the 23 tumors from patients with the familial breast and ovarian cancer syndrome, and all three tumors from two patients with the Li-Fraumeni syndrome. There was complete concordance between p53 gene mutation and p53 protein accumulation in the 15 snap-frozen carcinomas and in both breast carcinoma cell lines. Statistically significant associations of p53 protein accumulation with estrogen receptor negativity and with high nuclear grade were found. There were statistically significant associations, independent of other prognostic factors, between p53 protein accumulation and metastasis-free and overall survival, for randomly accrued and for both sporadic and familial tumors. Conclusions Immunohistochemically detected p53 protein accumulation was an independent marker of shortened survival and was seen more often in familial than in sporadic carcinomas. Our findings also suggest a correlation between p53 protein accumulation and p53 gene mutation.

746 citations


Journal ArticleDOI
TL;DR: Higher anxiety was directly related to poor attendance at a clinical breast examination and poor adherence to monthly breast self-examination and the impact of this information on their surveillance behaviors and psychological distress.
Abstract: Women with a family history of breast cancer are at increased risk for developing the disease. This study investigated the beliefs of women at high risk for breast cancer (one or more first-degree relatives with breast cancer) about their breast cancer risk and the impact of this information on their surveillance behaviors and psychological distress. The Health Belief Model and the Fear Arousing Communications Theory were used in this study. Two hundred and seventeen women, enrolled in a breast protection program, completed a questionnaire regarding health beliefs and behaviors, social support, and psychological distress. While 94% came in for regularly scheduled mammograms, only 69% came in for regular clinical breast examinations. A discriminant function analysis revealed that increased cancer anxiety decreased regular clinical examinations (coefficient = -.65). Only 40% performed breast self-examination monthly, 10% never performed breast self-examination, and 50% did not perform breast self-examination regularly. High breast self-examination performance prior to coming to the program was the best predictor of current breast self-examination, and high anxiety predicted poor adherence to monthly breast self-examination (multiple R = .61). More than 27% of the women at high risk were defined as having a level of psychological distress consistent with the need for counseling. Women reporting more barriers to screening, fewer social supports, and low social desirability had more psychological distress (multiple R = .75). Higher anxiety was directly related to poor attendance at a clinical breast examination and poor adherence to monthly breast self-examination.(ABSTRACT TRUNCATED AT 250 WORDS)

562 citations


Journal ArticleDOI
TL;DR: This analysis provides substantive evidence that intake of fiber-rich foods is inversely related to risk of cancers of both the colon and rectum and estimates that risk of colorectal cancer in the U.S. population could be reduced about 31% by an average increase in fiber intake from food sources of about 13 g/d.
Abstract: BACKGROUND Colorectal cancer is a major public health problem in both North America and western Europe, and incidence and mortality rates are rapidly increasing in many previously low-risk countries. It has been hypothesized that increased intakes of fiber, vitamin C, and beta carotene could decrease the risk of colorectal cancer. PURPOSE The objective of this study was to examine the effects of fiber, vitamin C, and beta-carotene intakes on colorectal cancer risk in a combined analysis of data from 13 case-control studies previously conducted in populations with differing colorectal cancer rates and dietary practices. The study was designed to estimate risks in the pooled data, to test the consistency of the associations across the studies, and to examine interactions of the effects of the nutrients with cancer site, sex, and age. METHODS Original data records for 5287 case subjects with colorectal cancer and 10,470 control subjects without disease were combined. Logistic regression analysis was used to estimate relative risks and confidence intervals for intakes of fiber, vitamin C, and beta carotene, with the effects of study, sex, and age group being adjusted by stratification. RESULTS Risk decreased as fiber intake increased; relative risks were 0.79, 0.69, 0.63, and 0.53 for the four highest quintiles of intake compared with the lowest quintile (trend, P < .0001). The inverse association with fiber is seen in 12 of the 13 studies and is similar in magnitude for left- and right-sided colon and rectal cancers, for men and for women, and for different age groups. In contrast, after adjustment for fiber intake, only weak inverse associations are seen for the intakes of vitamin C and beta carotene. CONCLUSION This analysis provides substantive evidence that intake of fiber-rich foods is inversely related to risk of cancers of both the colon and rectum. IMPLICATIONS If causality is assumed, we estimate that risk of colorectal cancer in the U.S. population could be reduced about 31% (50,000 cases annually) by an average increase in fiber intake from food sources of about 13 g/d, corresponding to an average increase of about 70%.

497 citations


Journal ArticleDOI
TL;DR: Breast irradiation significantly reduces breast relapse, but it does not influence survival, and systemic adjuvant therapy should be considered for patients with poor nuclear grade tumors.
Abstract: Background Although the conservation management of breast cancer has become a routine method of treatment in most centers, there is still considerable controversy surrounding the ultimate minimum treatment required for node-negative breast cancer to achieve adequate local control. Purpose Our purpose was to assess the value of breast irradiation in reducing breast relapse following conservation surgery for node-negative breast cancer. We attempted to define low-risk groups of women for breast and distant site relapse (i.e., recurrence outside the breast) who might be spared breast irradiation or adjuvant systemic therapy. Methods Eight hundred thirty-seven patients were randomly assigned to receive radiation therapy or no radiation therapy following lumpectomy and axillary dissection for node-negative breast cancer. Results Breast irradiation reduced relapse in the breast from 25.7% in the controls to 5.5% in the irradiated patients. There was no difference in survival between the two groups (median follow-up, 43 months). A low-risk group (less than 5% chance of relapse in the breast without irradiation) could not be defined. Tumor size (greater than 2 cm), age (less than 40 years), and poor nuclear grade were important predictors for breast relapse. Age (less than 50 years) and poor nuclear grade were important predictors for mortality. The presence of ductal carcinoma in situ did not predict breast relapse. Conclusions Breast irradiation significantly reduces breast relapse, but it does not influence survival. Important predictors of breast relapse are age, tumor size, and nuclear grade, but not the presence of ductal carcinoma in situ. Age and, in particular, nuclear grade predict survival. Implications Further follow-up may define an acceptable low-risk group for breast relapse. Until then, we recommend that all patients receive breast irradiation. Systemic adjuvant therapy should be considered for patients with poor nuclear grade tumors.

396 citations


Journal ArticleDOI
TL;DR: Recommendations that increased consumption of vegetables and grains may reduce the risk of fatal colon cancer are supported, and regular use of low doses of aspirin may prove to be an important supplemental measure.
Abstract: BACKGROUND Diet, physical activity, obesity, aspirin use, and family history may all modify the risk of colon cancer, but few epidemiologic studies are large enough to examine these factors simultaneously. PURPOSE We prospectively assessed the relationship of diet and other factors to risk of fatal colon cancer. METHODS Using data from Cancer Prevention Study II--an ongoing prospective mortality study--we studied 764,343 adults who, in 1982, completed a questionnaire on diet and other risk factors and did not report cancer or other major illness. We assessed mortality through August 1988 and identified 1150 deaths from colon cancer (611 men and 539 women). Multivariate analyses were used to compare these case patients with 5746 matched control subjects drawn from the cohort. RESULTS Risk of fatal colon cancer decreased with more frequent consumption of vegetables and high-fiber grains (P for trend = .031 in men and .0012 in women). The relative risk (RR) for the highest versus lowest quintile of vegetable intake was 0.76 in men (95% confidence interval [CI] = 0.57-1.02) and 0.62 in women (95% CI = 0.45-0.86). Dietary consumption of vegetables and grains and regular use of aspirin were the only factors having an independent and statistically significant association with fatal colon cancer. Participants who consumed the least vegetables and grains and no aspirin had a higher risk compared with those who consumed the most vegetables and used aspirin 16 or more times per month. For men in the former category, the RR was 2.4 (95% CI = 1.1-5.3); for women, it was 2.9 (95% CI = 1.3-6.7). Weaker associations were seen for physical inactivity, obesity, total dietary fat, and family history. No associations were seen with consumption of red meat or total or saturated fat in either sex, but this finding must be interpreted cautiously. CONCLUSIONS These findings support recommendations that increased consumption of vegetables and grains may reduce the risk of fatal colon cancer. Regular use of low doses of aspirin may prove to be an important supplemental measure.

392 citations


Journal ArticleDOI
TL;DR: Combined systemic therapy with 13-cRA and IFN alpha-2a is highly effective in patients with advanced squamous cell carcinoma of the skin, and the relationship between decreased response rate and increased extent of disease was highly statistically significant.
Abstract: Background Retinoids (vitamin A derivatives) and interferon-alpha (IFN-alpha) are potent regulators of malignant cell differentiation and proliferation, and both have immunomodulatory and antiangiogenesis activity. A large body of preclinical and clinical data supports the use of combination therapy with 13-cis-retinoic acid (13-cRA) and IFN-alpha in patients with squamous cell carcinoma of the skin. This carcinoma is an extremely common and frequently severely disfiguring cancer, for which about 10% of patients remain uncured following standard local therapy. Purpose Our purpose was to test whether a 20% or greater complete response rate could be achieved using a combination of these two agents in patients with advanced squamous cell carcinoma of the skin in whom local therapy had failed or was unfeasible or who had regional and/or distant metastases. Methods Thirty-two patients with heavily pretreated, advanced inoperable cutaneous squamous cell carcinoma of the skin were given a combination of oral 13-cRA (1 mg/kg per day) and subcutaneous recombinant human IFN alpha-2a (3 million units per day) for at least 2 months, unless disease progressed earlier, in a phase II trial. Results Nineteen (68%) of the 28 assessable patients responded, seven (25%) of whom had complete responses. Response rates were 93% (13 of 14) in patients with advanced local disease (six complete responses), 67% (four of six) in patients with regional disease (no complete responses), and 25% (two of eight) in patients with distant metastases (one complete response). The relationship between decreased response rate and increased extent of disease was highly statistically significant (P less than .005, chi-square test). The median response duration was greater than 5 months. No life-threatening toxic effects occurred in assessable patients treated with this combination, although dose reductions were required in 18 patients. The major limiting side effect in this elderly patient population (median age, 67 years) was cumulative fatigue. Conclusion These results indicate that combined systemic therapy with 13-cRA and IFN alpha-2a is highly effective in patients with advanced squamous cell carcinoma of the skin.

359 citations


Journal ArticleDOI
TL;DR: Overexpression of the p53 and c-erbB-2 proteins indicates a high malignant potential in ANN breast cancer, but it is not a significant prognostic factor independent of the cell proliferation rate.
Abstract: BACKGROUND Recent evidence indicates that a subset of axillary node-negative (ANN) breast cancer patients can benefit from adjuvant therapy. Reliable prognostic markers are needed, however, to help clinicians identify these patients and arrive at more rational treatment decisions. PURPOSE Mutations of the p53 tumor suppressor gene often result in overexpression of the p53 protein. In this study, we evaluated the prognostic significance of p53 protein overexpression in patients with ANN breast cancer. We also studied the association between the tumor cell proliferation rate and overexpression of the p53 and c-erbB-2 proteins, both of which have been implicated in cell cycle control. The c-erbB-2 protein is the product of the ERBB2 gene. METHODS Two hundred eighty-nine ANN cases were randomly selected from a population-based cohort of patients who had not received any kind of adjuvant chemotherapy or endocrine therapy. Overexpression of the p53 and c-erbB-2 proteins was studied immunohistochemically in archival paraffin-embedded tumor samples, using the CM-1 polyclonal and the TAb 250 monoclonal antibodies, respectively. The tumor cell proliferation rate was measured as the S-phase fraction by DNA flow cytometry. Statistical analyses were performed using BMDP software. RESULTS High-level p53 protein overexpression, found in 41 of the 289 tumors, was most common in tumors with high histologic grade, negative estrogen receptor status, c-erbB-2 protein overexpression, DNA index greater than 1.3, or high S-phase fraction. The lowest S-phase levels were found in tumors with neither p53 nor c-erbB-2 protein overexpression; the highest levels were seen in tumors showing overexpression of both proteins (P less than .0001). Both p53 and c-erbB-2 overexpression, as well as tumor size, had independent prognostic value in multivariate analysis. Eight-year survival of patients with p53 protein overexpression was 56% compared with 81% in patients with no overexpression (relative risk, 3.7; P less than .0001). If the S-phase fraction was included in a Cox regression analysis, however, only the tumor size and the S-phase fraction emerged as independent predictors of survival. CONCLUSIONS Overexpression of the p53 and c-erbB-2 proteins indicates a high malignant potential in ANN breast cancer, but it is not a significant prognostic factor independent of the cell proliferation rate. The correlation between overexpression of these proteins and an increased S-phase fraction suggests that they may confer a proliferative advantage to cancer cells in vivo.

348 citations


Journal ArticleDOI
TL;DR: The findings suggest that L86-8275 is a candidate for further preclinical development, as well as a model for the synthesis of other flavonoids that might potently delay cell cycle progression to achieve inhibition of tumor growth.
Abstract: Background Previous studies have shown that polyhydroxylated flavonoids such as quercetin and genistein can inhibit tumor cell growth in vitro, and preliminary in vivo studies of the flavone L86-8275 have shown growth inhibition of LX529 and A549 lung carcinomas. L86-8275 [(-)cis-5,7-dihydroxy-2-(2-chlorophenyl)-8[4-(3-hydroxy-1-methyl)- piperidinyl]-4H-1-benzopyran-4-one] is a flavone of novel structure. Purpose The purpose of this study was to determine in vitro whether L86-8275 is a more potent inhibitor of growth in breast carcinoma and lung carcinoma cells than quercetin or genistein. Methods We studied the effects of L86-8275 on cell growth in seven breast carcinoma cell lines and five lung carcinoma cell lines. MDA468 breast carcinoma was then selected for further study. Cell proliferation was measured by a colorimetric dye reduction assay; synthesis of DNA, RNA, and protein by incorporation of the radioactive metabolic precursors thymidine, uridine, or leucine, respectively; adenosine triphosphate (ATP) content by a luciferase-mediated bioluminescence reaction; and cell cycle progression by the use of cell-synchronizing drugs (aphidicolin and nocodazole) and flow cytometry. Results L86-8275 was not cytotoxic to stationary-phase cells but reversibly inhibited the growth of cells in exponential growth phase. At concentrations of 25-160 nM, L86-8275 inhibited growth of human breast and lung carcinoma cell lines by 50%. MDA468 breast carcinoma cells were 60-fold and 400-fold more sensitive to L86-8275 than to quercetin and genistein, respectively. By 24 hours after addition of L86-8275, DNA synthesis in MDA468 cells was inhibited by greater than 95%, protein synthesis by 80%, and RNA synthesis by 40%-60%, under conditions that preserved cellular ATP levels at approximately 80%-90% of control values. When MDA468 cells released from aphidicolin-induced cell cycle arrest were exposed to 200 nM L86-8275, they completed the S phase but arrested in G2. When cells released from nocodazole-induced cell cycle arrest were exposed to 200 nM L86-8275, they completed mitosis but arrested in G1. Conclusions L86-8275 is a potent, yet reversible, growth-inhibitory flavone that can selectively block cell cycle progression in vitro at more than one point in the cell cycle. Implications These findings suggest that L86-8275 is a candidate for further preclinical development, as well as a model for the synthesis of other flavonoids that might potently delay cell cycle progression to achieve inhibition of tumor growth. Future studies need to address optimal schedules for antiproliferative activity in vivo and inhibition of clonogenic activity.

347 citations


Journal ArticleDOI
TL;DR: The results suggest that tumors exhibiting decreased expression of the RB gene-coded product (Rb protein) had a more aggressive biological behavior than those that expressed the Rb protein in the majority of their tumor cells.
Abstract: Background It has been reported that 50%-70% of patients with bladder cancer experience recurrence after initial successful treatment and about 10%-20% of these patients die of the disease. Despite precise pathologic staging and grading, we are unable to predict clinical outcome in all patients. The retinoblastoma-susceptibility (RB) gene, a prototype of tumor suppressor genes, has recently been associated with development and/or progression of bladder cancer, as well as sarcoma and small-cell lung cancer. In transitional cell carcinomas of the bladder, we have observed altered expression of the Rb gene product--a nuclear phosphoprotein thought to function as a cell cycle regulator. Purpose The aim of this study was to investigate the hypothesis that altered patterns of Rb expression correlate with prognosis in bladder cancer. Methods Expression of the RB gene was evaluated in specimens from 48 primary bladder tumors obtained by cystectomy or transurethral resection. Rb protein expression was correlated with disease outcome in these patients. Rb expression was examined by immunohistochemistry, using the mouse monoclonal antibody Rb-PMG3-245 on frozen tissue sections. Computerized image analysis was used to quantify the level of Rb protein in individual tumor cells. Results The overall 5-year disease-free survival was 66%, with a median follow-up of 42 months. Normal levels of Rb protein expression were found in 34 patients (Rb-positive group). A spectrum of altered patterns of expression from undetectable levels to heterogeneous expression, however, was observed in 14 patients (altered Rb group). Of the 38 patients with muscle-invasive tumors, 13 were categorized as having altered expression of Rb protein. Only one of 10 patients with superficial carcinomas had altered expression of Rb protein. The 5-year survival was significantly decreased in patients with altered Rb protein compared with the survival in patients with positive Rb expression (P less than .001). Conclusions The results suggest that tumors exhibiting decreased expression of the RB gene-coded product (Rb protein) had a more aggressive biological behavior than those that expressed the Rb protein in the majority of their tumor cells. Implications This study demonstrates that altered patterns of Rb protein expression may be an important prognostic variable in patients presenting with invasive bladder cancer.

Journal ArticleDOI
TL;DR: These prospective data provide evidence for the hypothesis that a diet high in saturated fat and low in fiber increases the risk of colorectal adenoma and support existing recommendations to substitute chicken and fish for red meat in the diet and to increase intake of vegetables, fruits, and grains.
Abstract: Background Rates of colorectal cancer in various countries are strongly correlated with per-capita consumption of red meat and animal fat and inversely associated with fiber consumption. There have been few studies, however, of dietary risk factors for colorectal adenomas, which are precursors of cancer. Purpose Our purpose was to determine prospectively the relationship between dietary factors and risk of colorectal adenomas. Methods Using data from the Health Professionals Follow-up Study, we documented 170 cases of adenomas of the left colon or rectum in 7284 male health professionals who completed a food-frequency questionnaire in 1986 and who had a colonoscopy or sigmoidoscopy between 1986 and 1988. Relative risk (RR) of adenoma was determined according to quintiles of nutrient intakes. Results After adjustment for total energy intake, saturated fat was positively associated with risk of colorectal adenoma (P for trend = .006); RR for the highest versus the lowest quintile of intake was 2.0 (95% confidence interval [CI] = 1.2-3.2). Dietary fiber was inversely associated with risk of adenoma (P for trend less than .0001); RR for men in the highest versus the lowest quintile was 0.36 (95% CI = 0.22-0.60). All sources of fiber (vegetables, fruits, and grains) were associated with decreased risk of adenoma. For subjects on a high-saturated fat, low-fiber diet, the RR was 3.7 (95% CI = 1.5-8.8) compared with those on a low-saturated fat, high-fiber diet. The ratio of the intake of red meat to the intake of chicken and fish was positively associated with risk of adenoma (P for trend = .02). Conclusions These prospective data provide evidence for the hypothesis that a diet high in saturated fat and low in fiber increases the risk of colorectal adenoma. They also support existing recommendations to substitute chicken and fish for red meat in the diet and to increase intake of vegetables, fruits, and grains to reduce risk of colorectal cancer.


Journal ArticleDOI
TL;DR: The data suggest that the orthotopic injection of human prostate cancer cells into the nude mouse may provide a valuable model to study the biology and therapy ofhuman prostate cancer.
Abstract: Background Understanding the mechanism of prostate cancer metastasis is essential to the design of a more effective therapy. An effective therapy for this disease will depend on the development of a clinically relevant in vivo model. Purpose We describe the development of such a model by using orthotopic implantation of human prostate cells in BALB/c nude mice. Method We compared the tumorigenicity of and the incidence of metastasis of human prostate cancer PC-3M and LNCaP-FGC (LNCaP) cell lines subsequent to prostatic (orthotopic) or subcutaneous (ectopic) implantations in male nude mice. Results LNCaP cells produced tumors only in the prostate. Enhanced tumorigenicity at the orthotopic site was found for PC-3M cells. Lymph node metastases were observed in practically all mice given an injection of PC-3M cells in the prostate, but they were uncommon with subcutaneous injection of these cells. Bilateral orchiectomy did not alter the tumorigenicity of either PC-3M or LNCaP cells or the incidence of lymph node metastasis by PC-3M cells. LNCaP tumors in the mouse prostate (but not PC-3M tumors) elaborated detectable levels of human prostate-specific antigen (PSA) in the serum, even when tumors were small (1.5 mm in diameter). Immunohistochemistry analysis revealed the presence of the PSA marker in tissue sections of LNCaP but not of PC-3M tumors. Conclusions The implantation of human prostate cancer cells in an ectopic environment does not permit expression of metastatic potential. In contrast, intraprostatic implantation does. Implications These data suggest that the orthotopic injection of human prostate cancer cells into the nude mouse may provide a valuable model to study the biology and therapy of human prostate cancer.

Journal ArticleDOI
TL;DR: ERCC1 expression levels in human tumor tissue may have a role in clinical resistance to platinum compounds, and these data appear to be consistent with the assertion that ERCC1 serves as an excision nuclease, whereas ERCC2 serves as a helicase.
Abstract: BACKGROUND ERCC1 and ERCC2 are human DNA repair genes that are associated with in vitro resistance to selected DNA-damaging agents. PURPOSE Fresh tumor tissues from 26 patients with ovarian cancer were analyzed for the RNA levels of expression of these genes to determine possible clinical relevance. METHODS Tumor tissues were harvested from patients immediately before they entered a cisplatin- or carboplatin-based treatment protocol. Clinical response was assessed by standard criteria. Gene expression level was assessed by slot blot analysis, using beta-actin as a control. Relative expression levels were determined by comparing each tumor sample with a Chinese hamster ovary cell line that had a stable transfection of the human ERCC1 gene. RESULTS Patients who were clinically resistant to platinum-based therapy had a 2.6-fold higher expression level of ERCC1 in their tumor tissue than did patients who responded to that therapy (P = .015). Results obtained by slot blot analysis were qualitatively confirmed by polymerase chain reaction analysis. Relative levels of expression of ERCC2 did not differ significantly between responders and nonresponders. CONCLUSION We conclude that ERCC1 expression levels in human tumor tissue may have a role in clinical resistance to platinum compounds. These data appear to be consistent with the assertion that ERCC1 serves as an excision nuclease, whereas ERCC2 serves as a helicase.

Journal ArticleDOI
TL;DR: Accumulation of p53 confers proliferative advantage for prostatic carcinoma cells and defines a small subgroup of highly malignant carcinomas.
Abstract: BACKGROUND Mutations in the p53 gene resulting in the accumulation of altered p53 proteins with prolonged half-life have been found in a large variety of human malignancies. PURPOSE We studied the significance of p53 protein accumulation in prostatic carcinoma. METHODS The material consisted of 137 paraffin-embedded, primary prostatic carcinomas. Accumulation of p53 protein was studied by immunohistochemical staining using a polyclonal p53-specific CM-1 antibody. Proliferation activity was determined by DNA flow cytometry and by immunohistochemical detection of proliferative cell nuclear antigen (PCNA) using a monoclonal PC10 antibody. RESULTS Eight (6%) of the tumors showed intense p53 staining in more than 20% of the tumor cells, 15 (11%) had only lower level immunoreactivity, and 114 (83%) showed no staining. High-level p53 accumulation was associated with high histologic grade (P less than .001), DNA aneuploidy (P less than .05), and high cell proliferation rate as defined by flow cytometric S-phase analysis (P less than .01) or PCNA expression (P less than .01). High-level p53 accumulation predicted short, progression-free interval (P less than .01) and poor survival (P less than .001), with about a 12-fold relative risk of death as compared with p53-negative cases. Low-level p53 accumulation had no prognostic significance. CONCLUSIONS Accumulation of p53 confers proliferative advantage for prostatic carcinoma cells and defines a small subgroup of highly malignant carcinomas.

Journal ArticleDOI
TL;DR: In this paper, the authors conducted a phase II study of 13-cisretinoic acid (13-cRA) plus interferon-alpha (IFN-alpha) in cervical squamous cell carcinoma.
Abstract: BACKGROUND Chemotherapeutic study of cervical squamous cell carcinoma has shown some positive results. Complete plus partial (overall) response rates of 15%-35% (complete response rate, less than 5%) were achieved with the use of a small number of cytotoxic single agents in patients with advanced disease. In addition, overall response rates of 60%-70% (complete response rates, 10%-20%) were achieved with cisplatin-based, multiagent regimens in patients with primary, locally advanced disease. However, the lack of clear evidence that existing chemotherapy can achieve a survival benefit, coupled with the worldwide annual deaths of hundreds of thousands of women from cervical cancer, indicates the urgent need for effective systemic therapy for this disease. PURPOSE In view of the preclinical and clinical evidence that supports testing of the novel combination of 13-cis-retinoic acid (13-cRA) plus interferon-alpha (IFN-alpha) in cervical squamous cell carcinoma, we conducted a phase II study of this regimen in locally advanced disease. METHODS Twenty-six patients with untreated, locally advanced squamous cell carcinoma of the cervix were treated daily for at least 2 months with oral 13-cRA (1 mg/kg) and subcutaneous recombinant human IFN alpha-2a (6 million units). In 21 patients (81%), the disease was stage II or higher. RESULTS Thirteen patients (50%) experienced major responses (tumor regression greater than or equal to 50%) in association with resolution of symptoms; one achieved complete response, and 12 experienced partial response. Seven with partial response are improving further, four are being maintained in partial response, and one responder has relapsed during therapy. The response rate is 58% (11 of 19) in patients with stage IIB or higher disease and 66% (10 of 15) in patients with bulky disease (at least one dimension greater than or equal to 10 cm). Of the 13 non-responders, nine have stable disease and four have had disease progression during therapy. Toxicity was minimal. CONCLUSION These preliminary results indicate that systemic 13-cRA plus IFN alpha-2a is a highly active, well-tolerated therapy for locally advanced cervical cancer.

Journal ArticleDOI
TL;DR: Based on these and other studies, one future direction should be to determine the prognostic significance of p53 mutations as a function of the affected exon or domain.
Abstract: Biological studies of a limited number of p53 mutations suggest, for instance, that some p53 mutations are more \"oncogenic\" than others (6). Similarly, p53 genes having mutations in exons 5 and 6 encode proteins which bind heat shock protein (hsp) 70, whereas exons 7 and 8 mutant proteins do not (14). In this regard, Davidoff et al. (14) have found an association between breast tumors having mutations in exons 5 and 6 and those patients who show a humoral response to p53. In contrast, all of the patients who had a p53-positive tumor, but who were p53 antibody negative, had the mutation in exon 7 or 8. Based on these and other studies, one future direction should be to determine the prognostic significance of p53 mutations as a function of the affected exon or domain.

Journal ArticleDOI
TL;DR: It is demonstrated that in nontransformed C57/MG cells, 16 alpha-OHE1 may function as an initiator, perturbing the intermediate biomarkers for preneoplastic transformation.
Abstract: Background Estrogens are potent mammary tumor promoters influencing post-initiation events via epigenetic mechanisms. The upregulation (i.e., induction) of the C16 alpha-hydroxylation pathway during 17 beta-estradiol (E2) biotransformation has been associated with mammary cell transformation. The action of E2 metabolites on tumorigenic transformation, however, is poorly understood. Purpose The newly established mammary epithelial cell line C57/MG, derived from the C57BL mouse strain, was used to examine whether E2 or its metabolites, 16-hydroxyestrone (16 alpha-OHE1) and estriol (E3), function as initiators of mammary cell transformation. Methods DNA repair (hydroxyurea-insensitive thymidine uptake), estrogen metabolism (3H exchange to form 3H2O), hyperproliferation (increased cell number), and acquisition of anchorage-independent growth (soft-agar colonies) were used as quantitative end points to measure the relative extent of transformation. Results Treatment of cells with 200 ng/mL 16 alpha-OHE1 resulted in a 55.2% increase in DNA repair synthesis, a 23.09% increase in proliferative activity, and a 18-fold increase in the number of soft-agar colonies, relative to the solvent controls (P less than .0001). The extent of upregulation of the three end points was similar to that induced by the genotoxic mammary carcinogen 7, 12-dimethylbenz[a]anthracene (DMBA, positive control). DMBA treatment also upregulated the ratio of 16 alpha/C2 hydroxylation of E2 leading to increased formation of 16 alpha-OHE1. E2 and E3 were not effective in upregulating these markers for transformation. Conclusion These results demonstrate that in nontransformed C57/MG cells, 16 alpha-OHE1 may function as an initiator, perturbing the intermediate biomarkers for preneoplastic transformation.

Journal ArticleDOI
TL;DR: Although increased awareness and earlier diagnosis appear to have accompanied increased incidence, increased exposure to solar UV radiation during the past 50 years appears to be the most likely explanation for the rise in incidence rates.
Abstract: BackgTf!und: Queensland, Australia, had the world's highest incidence rates of invasive cutaneops melanoma' in the 1970s: Purpose: Th~ purPose of this study was to monitor trends in melanoma incidence in Queensland Methods: We studied two time periods in which ascertainment was compar­ able Results: In the 75 years up to 1987, the incidence of invasive melanoma in Queensland increased by more than one half in· women (to 4289 per 100 O~O) and more than doubled in men (to 5581 per 1000(}9); with the most dramatic increase seen in men over age 50 years This higber increase in men is a reversal C)f the previously higber rates in women In

Journal ArticleDOI
TL;DR: ER-negative breast cancer cells stably transfected with either a mutant or wild-type ER gene regain hormonal responsiveness; however, E2 inhibits rather than stimulates cell growth.
Abstract: Background The growth of estrogen receptor (ER)-positive breast cancer cells is hormonally regulated, but the majority of breast cancers are ER negative and unresponsive to hormonal therapy. Purpose and methods To test whether hormonal control over replication can be re-established in ER-negative cells, we transfected ER-negative MDA-MB-231 (clone 10A) cells with sense and antisense constitutive ER expression vectors containing the gene for either wild-type or mutant ER linked to the gene for neomycin resistance aminoglycoside phosphotransferase (neo). A Northern blot analysis was done on total RNA from eight of the 10 transfectant clones produced to detect messenger RNA coding for ER and neo, and a Western blot analysis was done on protein extracted from the cells of one mutant and two wild-type ER sense transfectant clones to determine the molecular weight of the ER in transfectants. Levels of ER in transfectants were measured both by enzyme immunoassay and by ligand-binding methods. To ascertain whether the ER in wild-type and mutant sense transfectants was functional, we tested the effects of 17 beta-estradiol (E2) and/or an antiestrogen, ICI 164,384, on 1) ER-activated gene regulation (by transient transfection of these cells a second time with a reporter plasmid containing an estrogen response element linked to the chloramphenicol acetyl transferase [CAT] gene), 2) induction of progesterone receptor, 3) DNA replication, and 4) cell cycle kinetics. Results Messenger RNA coding for ER and for neo was detectable in both sense and antisense transfectant clones. Sense transfectants (both mutant and wild-type) expressed ER protein with a molecular weight similar to that found in ER-positive control cells. By the ligand-binding method high levels of ER were detected in both wild-type and mutant transfectants, although by the enzyme immunoassay method lower levels were detected in mutant transfectants. ER from both wild-type and mutant sense transfectants appeared functional, since E2 stimulated the expression of reporter-linked CAT and of progesterone receptor in these transfectants. E2 inhibited DNA replication in wild-type sense transfectants at a concentration of 10(-10) M and mutant sense transfectants at a concentration of 10(-8) M, and ICI 164,384 blocked this effect. Conclusion ER-negative breast cancer cells stably transfected with either a mutant or wild-type ER gene regain hormonal responsiveness; however, E2 inhibits rather than stimulates cell growth. Implication Reactivation of quiescent ER may provide a novel therapeutic approach for controlling ER-negative breast cancers.


Journal ArticleDOI
TL;DR: The high frequency of Rb alteration in locally advanced bladder carcinomas, plus the fact that a significant correlation could not be found between the Rb status and other known prognostic markers in this preliminary study, suggests that altered RB expression may be an independent prognostic marker of tumor progression in bladder cancer.
Abstract: Background The clinical behavior of the tumor in patients with locally advanced bladder carcinoma is unpredictable. Current predictors of clinical behavior include depth of muscle invasion, presence of vascular invasion, proliferation rate, and loss of blood group antigens. Treatment selection would be facilitated by the development of a reliable marker of tumor progression. Functional retinoblastoma (RB) gene loss has been reported to occur in bladder carcinoma, but the significance of this loss is unknown. Purpose We have evaluated the frequency of functional loss of the RB gene in locally advanced bladder carcinoma and have compared the results to known prognostic factors in the same cohort. Methods Forty-three study patients with pathologically well-characterized, locally advanced bladder carcinoma, who were placed in a protocol incorporating surgery and chemotherapy, were studied for known clinical and pathological prognostic indicators as well as for their Rb status. Formalin-fixed and paraffin-embedded archival primary tumor tissues were used for histological and immunohistochemical analyses. Results Altered Rb protein expression was documented in 37% of the tumor specimens. The high rate of altered Rb expression found in this cohort with advanced urothelial tumors strongly suggests that RB functional loss may be associated with tumor progression in this malignancy. Altered Rb protein expression was found to be independent of other known prognostic variables. A significantly poorer tumor-free survival rate also was noted for those patients who had a tumor with an altered Rb protein with or without vascular invasion. Conclusion The high frequency of Rb alteration in locally advanced bladder carcinomas, plus the fact that a significant correlation could not be found between the Rb status and other known prognostic markers in this preliminary study, suggests that altered RB expression may be an independent prognostic marker of tumor progression in bladder cancer.

Journal ArticleDOI
TL;DR: Many of the problems that quality-of-life studies have encountered could be addressed and alleviated during protocol development, and this discussion is intended to assist and stimulate investigators conducting research in this area.
Abstract: Background Interest in incorporating quality of life as an end point in clinical studies of cancer treatment has intensified in recent years. Purpose We provide practical suggestions that will assist investigators considering including quality-of-life assessment in phase III therapeutic trials. Methods We discuss issues important in study planning, including quality-of-life definition, priority studies for quality-of-life assessment, eligibility requirements, and design. Conclusions Many of the problems that quality-of-life studies have encountered, from protocol approval to data analysis, could be addressed and alleviated during protocol development. This discussion is intended to assist and stimulate investigators conducting research in this area.

Journal ArticleDOI
TL;DR: It is demonstrated that antitumor activity can be induced with the use of a recombinant CEA-vaccinia virus construct derived from an attenuated vaccinia strain, and the range of cell-mediated and humoral responses induced by this recombinant vaccine is revealed.
Abstract: BACKGROUND Human carcinoembryonic antigen (CEA) is a 180-kd glycoprotein expressed in human colorectal, gastric, pancreatic, breast, and non-small-cell lung carcinomas. Previous studies have demonstrated enhanced immune responses to other antigens presented with vaccinia virus proteins via a recombinant vaccinia virus construct. In addition, we have developed a recombinant CEA-vaccinia virus construct, designated rV(WR)-CEA, and have demonstrated humoral anti-CEA responses in mice after immunization with that virus. PURPOSE The goals of this study were (a) to construct a recombinant CEA-vaccinia vaccine in a less virulent vaccinia strain that is potentially safe and effective for treatment of patients whose tumors express CEA and (b) to evaluate the ability of the recombinant CEA-vaccinia vaccine to prevent and reverse tumor growth in mice and to elicit cell-mediated and humoral anti-CEA immune responses. METHODS Using the New York City strain of vaccinia virus, which is used in smallpox vaccination and is more attenuated for humans than rV(WR), we derived a recombinant CEA-vaccinia construct, designated rV(NYC)-CEA. The ability of this construct to induce antitumor immunity was evaluated in mice receiving subcutaneous injections of murine colon adenocarcinoma cells expressing the human CEA gene. RESULTS Administration of rV(NYC)-CEA in mice induced strong anti-CEA antibody responses, as well as CEA-specific cell-mediated responses, including delayed-type hypersensitivity, lymphoproliferative, and cytotoxic responses. Vaccination of mice with the rV(NYC)-CEA rendered them resistant to the growth of subsequently transplanted CEA-expressing tumors. Moreover, when mice were vaccinated 7 days after tumor cell injection, tumor growth was either greatly reduced or eliminated. No toxic effects were observed in any of the mice. CONCLUSION These studies demonstrate that antitumor activity can be induced with the use of a recombinant CEA-vaccinia virus construct derived from an attenuated vaccinia strain, and they reveal the range of cell-mediated and humoral responses induced by this recombinant vaccine.

Journal ArticleDOI
TL;DR: The pattern of cancer excesses suggests a susceptibility state permitting the development of selected second malignancies in patients with CLL, perhaps because of shared etiologic factors, immunologic impairment, and/or other influences.
Abstract: BACKGROUND Reports to date have provided widely divergent estimates of the risk of second malignant neoplasms in patients with chronic lymphocytic leukemia (CLL), ranging from cancer deficits to excesses of twofold to threefold. PURPOSE Our purpose was to estimate the risk of second primary cancers following CLL, utilizing population-based tumor registries, and to determine whether site-specific excesses might be associated with type of initial treatment for CLL. METHODS We analyzed data for 9456 patients diagnosed with CLL as a first primary cancer between 1973 and 1988, who were reported to one of nine tumor registries participating in the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) Program and who survived 2 or more months. SEER files were searched for invasive primary malignancies that developed at least 2 months after the initial CLL diagnosis. RESULTS Compared with the general population, CLL patients demonstrated a significantly increased risk of developing all second cancers (840 observed; observed-to-expected ratio [O/E] = 1.28; 95% confidence interval [CI] = 1.19-1.37). Significant excesses were noted for cancers of the lung (O/E = 1.90), brain (O/E = 1.98), and eye (intraocular melanoma) (O/E = 3.97) as well as malignant melanoma (O/E = 2.79) and Hodgkin's disease (O/E = 7.69). Cancer risk, which did not vary according to initial treatment category, was also constant across all time intervals after CLL diagnosis. CONCLUSION CLL patients are at a significantly increased risk of developing a second malignant neoplasm. The pattern of cancer excesses suggests a susceptibility state permitting the development of selected second malignancies in patients with CLL, perhaps because of shared etiologic factors, immunologic impairment, and/or other influences. Although our results do not suggest a strong treatment effect, more detailed studies of second tumors in CLL are needed to investigate the role of radiation therapy and chemotherapy.

Journal ArticleDOI
TL;DR: A modest positive association of total fat intake with risk of breast cancer was seen, consistent with studies suggesting that fat intake is a determinant of Breast cancer, particularly after accounting for inaccuracies in dietary assessment.
Abstract: BACKGROUND: Although the results of animal studies and cross-cultural comparisons generally support a role for dietary fat in the etiology of breast cancer, results of analytic epidemiology studies are equivocal. PURPOSE: The association between dietary fat and subsequent breast cancer was examined in a cohort of 34,388 postmenopausal women from Iowa. METHODS: Dietary habits were assessed by a food-frequency questionnaire mailed in January 1986. Through December 31, 1989, 459 incident cases of breast cancer occurred in this cohort. Proportional hazards regression was used to examine the dietary fat-breast cancer association while adjusting for potential confounders. The effects on this association of four analytic approaches to adjustment for energy intake were also considered. RESULTS: After adjustment for known determinants of breast cancer, a modest positive association of total fat intake with risk of breast cancer was seen. Polyunsaturated fat intake was also positively associated with breast cancer (relative risk from lowest to highest intake, 1.0, 1.25, 1.31, and 1.49; P for trend = .052). Different approaches to adjustment for energy intake, however, provided different impressions of the dietary fat-breast cancer association. One method, involving categorization of crude fat intake and inclusion of total energy intake in regression analysis, gave relative risk estimates from low to high fat intake of 1.0, 1.17, 1.25, and 1.38 (P for trend = .18). Another method, based on categorization of fat intake residuals in which the variation in fat due to total energy intake was removed, gave corresponding estimates of 1.0, 1.24, 1.30, and 1.16 (P for trend = .29). The former suggests increasing breast cancer risk with increasing fat intake; the latter suggests no association. CONCLUSIONS: These results are consistent with other cohort studies that have shown a weak association or no association between dietary fat and breast cancer. They are also consistent with studies suggesting that fat intake is a determinant of breast cancer, particularly after accounting for inaccuracies in dietary assessment. The effects of different energy-adjustment methods may account in part for the varying interpretations of four previous cohort studies of dietary fat and breast cancer. IMPLICATIONS: Further work is needed to clarify not only the nature of the dietary fat-breast cancer association, but also the impact of different analytic methods used in the investigation of diet-disease associations.

Journal ArticleDOI
L. Ma, E. Fishell1, B. Wright1, Wedad Hanna1, S. Allan, Norman F. Boyd 
TL;DR: The results indicate that biologic factors are associated with failure to detect some breast cancers by mammography and indicate directions for future research in breast imaging.
Abstract: BACKGROUND Although mammography is widely used to detect breast cancer, it is recognized that not all cancers can be seen on mammographic images. PURPOSE Our purpose was to examine factors associated with failure to detect breast cancer by mammography. METHODS A case-control study was carried out in which subjects in whom histologically verified breast cancer was not detected by mammography (false negatives) were contrasted with subjects in whom breast cancer had been detected by mammography (true positives). Mammograms from individuals with histologically confirmed breast cancer were classified independently by two radiologists who were unaware of the clinical or other characteristics of the subjects. Histologic slides of all tumors were reviewed by one pathologist. RESULTS Three variables were found to be independently and significantly associated with failure to detect breast cancer by mammography. Breast cancer was less likely to be detected by mammography in the presence of extensive parenchymal densities (odds ratio [OR] = 9; 95% confidence interval [CI] = 1.8-44.3), a tumor of lobular histology (OR = 7; 95% CI = 2.2-22.1), and tumors of small size (OR = 0.10; 95% CI = 0.0-0.9). CONCLUSION Our results indicate that biologic factors are associated with failure to detect some breast cancers by mammography and indicate directions for future research in breast imaging.

Journal ArticleDOI
TL;DR: This study demonstrates that high-dose tamoxifen can be safely administered and that plasma concentrations that may inhibit P-glycoprotein function can be achieved, and recommends this dose for phase II trials of tamoxIFen to modulate P- Glycoprotein-mediated drug resistance.
Abstract: Background P-glycoprotein mediates resistance to natural-product anti-neoplastic agents like vinblastine through an active transport process resulting in reduced intracellular concentration of these agents. The triphenylethylene antiestrogen tamoxifen and its major metabolite N-desmethyltamoxifen at concentrations of 4-6 microM enhance the intracellular concentration of natural-product antineoplastics and augment the cytotoxicity of such drugs three-fold to 10-fold in a variety of human and murine cell lines. Purpose On the basis of these preclinical findings, we conducted a phase I clinical trial of high-dose, oral tamoxifen administered in conjunction with a 5-day continuous infusion of vinblastine. Methods We studied 53 patients with advanced epithelial tumors. Tamoxifen was given orally as a loading dose on day 1, followed by two doses a day on days 2-13. Vinblastine was given as a 120-hour continuous infusion (1.5 mg/m2 per day) on days 9-13 of each tamoxifen course. The starting dose of tamoxifen was 40 mg/m2 administered twice a day following a loading dose of 150 mg/m2. The maximum dose was 260 mg/m2 twice a day following a loading dose of 680 mg/m2. Treatment cycles were repeated every 28 days. Results The dose-limiting toxic effects of tamoxifen were neurologic and began within 3-5 days after the start of treatment. They consisted of tremor, hyperreflexia, dysmetria, unsteady gait, and dizziness. One patient experienced a grand mal seizure 24 hours after the last tamoxifen dose. Toxic effects were rapidly reversible. Asymptomatic prolongation of the QT interval on electrocardiogram occurred at doses of tamoxifen of 80 mg/m2 or higher given twice a day. No coagulation or ophthalmologic abnormalities occurred. Tamoxifen did not enhance the toxicity of vinblastine. Mean plasma concentrations of tamoxifen or N-desmethyltamoxifen at 260 mg/m2 tamoxifen given twice a day for 13 days were 6.04 and 6.56 microM, respectively. There was no relationship between plasma antiestrogen content and the development of neurotoxic effects. Conclusions Tamoxifen at 150 mg/m2 given twice a day following a loading dose of 400 mg/m2 results in plasma levels of tamoxifen and N-desmethyltamoxifen of 4 and 6 microM, respectively, without dose-limiting toxicity. We recommend this dose for phase II trials of tamoxifen to modulate P-glycoprotein-mediated drug resistance. Implications Our study demonstrates that high-dose tamoxifen can be safely administered and that plasma concentrations that may inhibit P-glycoprotein function can be achieved.

Journal ArticleDOI
TL;DR: These findings imply that the galactose-containing carbohydrate side chains of CP might mimic or compete with the natural ligand(s) of the tumor galactoside-binding protein (gal-lectin) and thus affect cellular interactions relevant for metastasis.
Abstract: Context Studies have shown that the galactoside-containing simple sugars and anti-galactoside-binding lectin antibodies may affect experimental tumor cell metastasis. However, the limited number of reagents used thus far necessitate further observations. Purpose Natural citrus pectin (CP) and pH-modified CP (MCP), rich in galactose residues, were used to study the involvement of carbohydrates containing galactoside residues in cellular interaction in vitro and in lung colonization in vivo of B16-F1 melanoma cells. Methods B16-F1 melanoma cells were incubated with various concentrations of CP and MCP. Their ability to form homotypic aggregation in vitro and tumor lung colonization in vivo in 8-week-old female C57BL/6 mice was then analyzed. Results The CP binds to the surface of B16-F1 melanoma cells; this binding can be inhibited by lactose at a concentration of 0.15 M. Intravenous injection of the murine B16-F1 melanoma cells with the natural CP resulted in a significant increase (up to threefold) in the appearance of tumor colonies in the lung and in increased homotypic aggregation properties of the cells, while injection of MCP significantly decreased B16-F1 experimental metastasis (greater than 90%). Conclusions Tumor galactoside-binding proteins mediate cellular recognition by linking oligosaccharides with terminal D-galactoside residues on adjacent cells. Successful interference with such a process with MCP may lead to a reduced ability to form tumor cell emboli and metastasis. Implications These findings imply that the galactose-containing carbohydrate side chains of CP might mimic or compete with the natural ligand(s) of the tumor galactoside-binding protein (gal-lectin) and thus affect cellular interactions relevant for metastasis.