Showing papers by "International Agency for Research on Cancer published in 1987"

Statistical methods in cancer research. Volume II--The design and analysis of cohort studies.

Abstract: What do you do to start reading statistical methods in cancer research vol ii the design and analysis of cohort studies? Searching the book that you love to read first or find an interesting book that will make you want to read? Everybody has difference with their reason of reading a book. Actuary, reading habit must be from earlier. Many people may be love to read, but not a book. It's not fault. Someone will be bored to open the thick book with small words to read. In more, this is the real condition. So do happen probably with this statistical methods in cancer research vol ii the design and analysis of cohort studies.

Second malignancies following testicular cancer, ovarian cancer and Hodgkin's disease: an international collaborative study among cancer registries.

Abstract: Eleven population-based cancer registries tabulated second cancers among 133,411 patients diagnosed with testicular cancer, ovarian cancer or Hodgkin's disease between 1945 and 1984 Overall, 3,157 second cancers were observed, as compared with 2,420 expected at least one year after the first cancer Survivors of testicular and ovarian cancer experienced 30% and 20% more cancers respectively than the general population comparison group, and patients previously diagnosed with Hodgkin's disease had an 80% excess of cancer No information was available either on treatment for the first cancer, or other risk factors However, temporal patterns in the risk of specific second cancers were analysed, with particular reference to the possible role of therapy for the first cancer Leukaemia of the acute or non-lymphatic type, which has been previously linked to alkylating agent therapy, occurred in excess following all 3 first cancers, as did non-Hodgkin's lymphoma (overall relative risks of 61 and 18 respectively, with considerably higher relative risks following Hodgkin's disease) Other cancers for which important and plausibly therapy-induced excesses occurred were lung cancer following Hodgkin's disease (relative risk 19), breast cancer following Hodgkin's disease (relative risk 14) and bladder cancer following ovarian cancer and Hodgkin's disease (relative risks 17 and 22 in women, respectively) Rarer sites at which striking excesses occurred were the salivary gland, thyroid, bone and connective tissue There were smaller, but clear excesses for cancers of the rectum and colon following ovarian cancer and testicular cancer, skin cancer following Hodgkin's disease, and kidney cancer following ovarian cancer Overdiagnosis, misclassification of metastases and confounding by other risk factors were all considered as explanations of observed excesses Nonetheless, it appeared that there are clear excess risks for cancers other than acute leukaemia which must be ascribed to therapy for the first cancer, especially in view of the possible under-reporting in registry material Case-control studies are under way to provide information on the role of specific aspects of therapy

Epstein-Barr virus (EBV) induces expression of B-cell activation markers on in vitro infection of EBV-negative B-lymphoma cells.

Abstract: A set of B-cell activation markers, including the EBV/C3d receptor [complement receptor type 2 (CR2) (CD21)], the 45-kDa lymphoblastoid cell-associated (Blast-2) antigen (CD23), and the B-cell restricted activation (Bac-1) antigen (which was recently identified as a potential B-cell growth factor receptor) can be turned on by infecting lymphoma cells that are genome negative for Epstein-Barr virus (EBV) with the B95-8 immortalizing strain of the virus. The nonimmortalizing EBV variant, strain P3HR-1, which possesses a deletion within the BamHI WYH region of the genome containing the coding sequence for the EBV-determined nuclear antigen 2, does not induce expression of these markers. Other lymphoblastoid cell-associated antigen markers can be activated by infection with either immortalizing or nonimmortalizing viruses. These results suggest that the immortalizing potential of EBV is correlated with its ability to induce expression of B-cell activation markers, which are suspected to play a major role in the physiological pathway leading to lymphoid cell proliferation. The viral genomic region deleted in the nonimmortalizing strain of EBV seems to be required for activation of some of these markers. Human lymphoma cell lines, such as those used in this study, can thus help identify the specific EBV genes involved in lymphoid B-cell proliferation and the mechanism of action of these genes.

Aflatoxin exposure, hepatitis B virus infection and liver cancer in Swaziland.

Abstract: A study was carried out in Swaziland to assess the relationship between aflatoxin exposure, hepatitis B infection, and the incidence of liver-cell carcinoma, which is the most commonly occurring malignancy among males in Swaziland. Levels of aflatoxin intake were evaluated in dietary samples from households across the country, and crop samples taken from representative farms. Prevalence of hepatitis B markers was estimated from the serum of blood donors, and liver cancer incidence was recorded for the years 1979-83 through a national system of cancer registration. Across 4 broad geographic regions, there was a more than 5-fold variation in the estimated daily intake of aflatoxin, ranging from 3.1 to 17.5 micrograms. The proportion of HBV-exposed individuals was very high (86% in men), but varied relatively little by geographic region; the prevalence of carriers of the surface antigen was 23% in men, and varied from 21 to 28%. Liver cancer incidence varied over a 5-fold range, and was strongly associated with estimated levels of aflatoxin. In an analysis involving 10 smaller subregions, aflatoxin exposure emerged as a more important determinant of the variation in liver cancer incidence than the prevalence of hepatitis infection. Aflatoxin estimates from crop samples appeared to be a reasonable surrogate for dietary measurements. A comparison with dietary aflatoxin levels measured in an earlier survey in Swaziland suggested that programmes aimed at reducing contamination levels had had some success.

Epidemiological and environmental evidence of the health effects of exposure to erionite fibres: a four-year study in the cappadocian region of Turkey

Abstract: An environmental and epidemiological study has been carried out in Central Cappadocia, Turkey, aiming at investigating the relationship between exposure to naturally occurring erionite fibres and the reported high incidence of malignant mesotheliomas. Airborne fibre levels are generally low but show a higher proportion of erionite fibres in the villages affected by malignant disease than in a control village. The same pattern is confirmed by analysis of the fibre content in lung tissues of sheep from several villages, both affected and unaffected by malignant disease. The 3 villages with the highest proportion of erionite fibres have high rates of malignant pleural mesothelioma, malignant peritoneal mesothelioma and lung cancer. No case of malignancy for the same sites has been reported during the study period from the control village. The relationships between these findings and their consistency with the results from experimental studies indicate erionite fibres as a carcinogenic agent, although some aspects of the exposure are not fully clarified.

Hot beverages and oesophageal cancer in southern Brazil: a case-control study

Abstract: There is a cluster of high-incidence areas of oesophageal cancer in south-eastern South America, including Southern Brazil, Uruguay and parts of Argentina. The present case-control study investigated the hypothesis that this may be due to the drinking of mate, a traditional beverage drunk at a very high temperature, and also studied the role of other known risk factors such as alcohol and tobacco. Cases (171) and age- and sex-matched controls (342) were recruited from hospitals in the State of Rio Grande do Sul in Southern Brazil. The crude odds ratio for daily mate drinkers was 1.92 relative to those drinking less frequently than daily (p = 0.006). Other risk factors included the drinking of cachaca (a sugar cane spirit), smoking, rural residence, low fruit consumption and high intake of meats. After adjustment for these variables through conditional logistic regression, the odds ratio associated with daily mate drinking was reduced to 1.47 (90% CI = 0.87-2.50). Although the study failed to provide evidence of a strong association between mate and oesophageal cancer, the cluster of high rates could be explained by relative risks of the magnitude observed. This is due to the fact that approximately 70% of adult males and 50% of females are daily drinkers. In addition, this study revealed that alcohol, tobacco smoking and rural residence are the main risk factors for oesophageal cancer in this population and the fruit consumption confers some degree of protection.

Colorectal cancer and the intake of nutrients: oligosaccharides are a risk factor, fats are not. A case-control study in Belgium.

Abstract: A case-control study was carried out in the populations of two Belgian provinces that differed in food consumption habits, particularly fat intake. There were 453 colonic and 365 rectal cancer cases and 2,851 population controls. There were no significant differences in the average intake of the major nutrients, with the exception of carbohydrates; patients had a larger intake, limited to oligosaccharides. In both provinces, in males and females having cancer of the colon or the rectum, the intake of linoleic acid was lower than among controls; for dietary fibers, a smaller intake was observed among patients in one province. The relative risks were computed for four levels of daily intake of each nutrient. A positive trend was found for oligosaccharides in all subgroups, and a negative trend was found for polysaccharides, the latter for colon cancer patients only. There was a constant and significant negative trend for linoleic acid, with a similar negative trend for dietary fiber. None of these trends were affected by further adjustment for total calorie intake. For several vitamins and minerals, less marked, less constant effects were observed. They tended to be negative for vitamin B1, vitamin B6, and iron; they were positive for retinol and vitamin B2.

Diet and esophageal cancer in calvados (France)

Abstract: The role of nutrients and food factors in relation to esophageal cancer was observed in a large case-control study in a region having a high incidence of the disease. Several factors that increased or decreased the risk were identified. After adjusting for other covariates, we found that animal proteins and polyunsaturated fats had a significant protective effect. Separating the effects of specific nutrients was difficult because of the intercorrelation between individual intakes of most nutrients. Foods were not so highly intercorrelated. Fresh meat, citrus fruits, and oil were found to be protective. A dietary index combining these foods was used; between the lowest and the highest levels of intake, a nine-fold difference in risk was observed. This effect is added to that of alcohol, which remains the major risk factor. The adequacy of the concepts of nutrients and foods in epidemiological studies is discussed in addition to the theoretical and practical implications of the findings.

Colorectal polyps and diet: a case-control study in Marseilles.

Abstract: This study investigates the differences in usual past diet between 252 subjects with newly diagnosed adenomatous or villous polyps of the colon and rectum and a group of 238 hospital controls. Cases and controls were interviewed in hospital by 3 nutritionists using a dietary history questionnaire focused on the diet during the preceding year. Nutrient intake was estimated by means of ad hoc food tables adapted from French and British tables. Out of 16 food groups considered in the analyses, the cases reported lower consumption of oil and potatoes and higher consumption of sugar added to food and drink. Among nutrients, we found that cases had a lower consumption of carbohydrates (not taking into account added sugar), potassium, magnesium and vitamin B6. We found a slightly lower intake of fibre and a slightly higher intake of saturated fat among cases, though neither was statistically significant. Intake values for fibre and for carbohydrates were highly intercorrelated and, due to measurement errors, the effect of one may be masked by the other and vice versa. The hypothesis that some components of carbohydrates (starches, fibre and natural sugars but not added sugar) play a protective role in relation to the biology of tumours of the intestinal tract is considered in further multivariate analyses and in the "Discussion".

Volatile nitrosamine levels in common foods from Tunisia, south China and Greenland, high-risk areas for nasopharyngeal carcinoma (NPC)

Abstract: On the basis of anthropological pilot studies on diet in Tunisia, south China and Greenland, food items consumed frequently by these populations at high risk for NPC were analysed for volatile nitrosamines using gas chromatography combined with a thermal energy analyzer. Relatively high levels of N-nitrosodimethylamine (NDMA), N-nitrosopyrrolidine (NPYR) and N-nitrosopiperidine (NPIP) were detected in Tunisian stewing base ("Touklia") and dried mutton preserved in olive oil ("Qaddid"). NDMA was also detected at levels ranging from trace amounts to 133 micrograms/kg in several Chinese salted and dried marine fish and in Greenland dried, unsalted fish preparations. NPYR and NPIP were also occasionally detected in several vegetables fermented in brine collected in Tunisia and China. The possible role of nitrosamines in the etiology of NPC is discussed.

Tobacco smoking, occupational exposure and bladder cancer in Argentina.

Abstract: The highest rate for bladder cancer in Latin America has been reported from La Plata, Argentina. A case-control study was carried out to investigate the reasons for this high rate. A total of 117 cases, 117 hospital controls and 117 neighbourhood sex- and age-matched controls were interviewed regarding their smoking and drinking habits and occupational exposures. Cigarette smoking and coffee drinking were identified as the major risk factors, and a significant association was also found for truck and railway drivers and for oil refinery workers. The relative risks for male smokers who ever smoked cigarettes vs. non-smokers was 4.3 (95% Cl: 1.9-10.3). The risk associated with black tobacco cigarettes was 2-3 times higher than that of blond cigarettes. For male ex-smokers the risk after 5 years of no smoking is less than one third of that of current smokers. The RR for drinking coffee was 2.4 (95% Cl: 1.4-4.4) after adjusting for the effects of tobacco smoking, and the risk increased with the number of cups per day. No association was found with the use of saccharin.

Hepatitis B virus, tobacco smoking and ethanol consumption in the etiology of hepatocellular carcinoma

Abstract: Tobacco smoking and alcohol drinking histories were obtained from 194 patients with hepatocellular carcinoma (HCC) and 456 hospital controls, and the results were analysed in conjunction with the results of serological determinations of hepatitis B surface antigen (HBsAg), antibody to HBsAg (anti-HBs) and antibody to hepatitis B core antigen (anti-HBc) in all subjects, as well as the presence or absence of cirrhosis in HCC patients. The relative risk (RR) of HCC (and 95% confidence interval) among HBsAg-positive subjects was 13.7 (8.0-23.5), whereas the excess risk among antibody-positive subjects was small and statistically non-significant. In the presence of cirrhosis the RR for HBsAg-positive subjects was considerably higher (30.7 vs. 7.1 among HBsAg-positive subjects without cirrhosis) indicating that HBV may affect the development of HCC through at least two different and potentially multiplicative mechanisms (DNA integration and liver regeneration). Moderate ethanol consumption does not affect the risk of HCC, but there is a statistically significant and dose-dependent association between tobacco smoking and HBsAg-negative HCC. In most of the developed countries of Europe and North America, where the prevalence of HBsAg carrier state is very low and tobacco smoking very common, more cases of HCC may be due to tobacco smoking than to HBV, even though the RR for HCC is much higher among HBsAg carriers than among tobacco smokers.

Selective Lack of Intercellular Communication between Transformed and Nontransformed Cells as a Common Property of Chemical and Oncogene Transformation of BALB/c 3T3 Cells

Abstract: BALB/c 3T3 cells can be transformed by transfection of an activated cellular oncogene as well as by chemicals. When the cells were transformed by pEJ-ras transfection, a marked increase in Mr 21,000 protein expression was found by Western blotting and immunohistochemical staining, whereas no such increase was detected in cells transformed by methylcholanthrene, suggesting two different molecular mechanisms. By directly microinjecting a fluorescent dye (Lucifer Yellow CH) into individual cells, we measured junctional intercellular communication among and between transformed and surrounding nontransformed cells. In both chemical and oncogene transformation studies, transformed cells and surrounding normal cells have similar capacities for gap-junctional communication, but there was complete lack of communication between transformed and nontransformed cells. When BALB/c 3T3 cells were transformed by methylcholanthrene initiation followed by phorbol ester promotion, again we saw no intercellular communication between transformed and nontransformed cells, suggesting that the observed selective communication block between transformed and nontransformed cells may be a general phenomenon in BALB/c 3T3 cells. These results indicate that selective lack of intercellular communication between transformed and surrounding normal cells may be an important phenomenon that separates transformed cells and nontransformed cells, permitting transformed cells to maintain autonomous growth.

Aflatoxin detected in human breast milk by immunoassay.

Abstract: Several epidemiological studies have shown a positive association between dietary exposure to aflatoxin (AF) and an increased incidence of primary hepatocellular carcinoma (PHC). One area in which little information is available is the exposure of newborn children to AF in human breast milk. We report the development, validation and application of an enzyme-linked immunosorbent assay (ELISA) to the detection of AF in human breast milk. The assay allows the quantitation of 2 pg AFM1 per ml of milk using less than 10 ml of sample. A good correlation was observed between ELISA and an hplc-fluorescence technique using naturally contaminated milk at levels up to 40 pg AF per ml. Of 54 samples collected from women in rural villages in Zimbabwe, 6 were found to be positive (11%) in ELISA with levels up to 50 pg AF per ml. No positive samples were detected out of 42 milk samples obtained from women in France. This sensitive and rapid methodology will be useful in examining the importance of and interaction between exposure to AF and infection with hepatitis B virus (HBV) early in life.

Evaluation of the genetic and embryotoxic effects of bis(tri-n-butyltin)oxide (TBTO), a broad-spectrum pesticide, in multiple in vivo and in vitro short-term tests

Abstract: The genetic and embryotoxic effects of bis(tri-n-butyltin)oxide (TBTO) were evaluated in multiple in vivo and in vitro short-term tests preparatory to its potential wide use as a molluscicide in control of schistosomiasis. When tested in the rec assay in Bacillus subtilis, TBTO was not mutagenic and it did not induce reverse mutations in Klebsiella pneumoniae. Neither in the presence nor in the absecne of rat liver activation system did TBTO produce point mutations in Salmonella typhimurium strains TA1530, TA1535, TA1538, TA97, TA98 or TA100. TBTO was matagenic in strain TA100 in a fluctuation test, but only in the presence of rat liver S9 (Aroclor-induced). TBTO did not induce gene mutations in the yeast Schizosaccharomyces pombe, mitotic gene conversions in the yeast Saccharomyces cerevisiae, nor sister-chromatid exchange in Chinese hamster ovary cells in the presence or absence of rat or mouse liver S9. In the latter cells, structural chromosomal aberrations, endoreduplicated and polyploid cells were induced. TBTO did not induce gene mutations in V79 Chinese hamster cells (to 8-azaguanine-, ouabain- or 6-thioguanine-resistance) in the presence of a rat liver postmitochondrial fraction or in cell (hamster embryo cells and human and mouse epidermal keratinocyte)-mediated assays. In mouse lymphoma cells, TBTO did not induce 6-thioguanine- or BUdR-resistant mutations. As many tumour promoters inhibit metabolic cooperation between V79 Chinese hamster 6-thioguanine-resistant/-sensitive cells, TBTO was tested but showed no such activity. TBTO was examined for the induction of recessive lethal mutations in adult Berlin K male Drosophila melanogaster, either by feeding or by injection. Doses of 0.37 or 0.74 mM did not increase the number of X-linked recessive lethal mutations. An increased number of micronuclei was observed in the polychromatic erythrocytes of male BALB/c mice 48 h after a single oral dose of TBTO (60 mg/kg bw), while a lower dose (30 mg/kg bw) was ineffective. Neither of the two doses had induced micronuclei 30 h after treatment. The reproductive toxicity of TBTO was studied in NMRI mice. In a 10-day toxicity study, the LD50 and LD10 were 74 and 34 mg/kg bw, respectively. An increased frequency of cleft palates was seen in the fetuses of mice (compared with controls, 0.7%) treated orally during pregnancy with 11.7 mg/kg TBTO (7%), 23.4 mg/kg (24%) or 35 mg/kg (48%).(ABSTRACT TRUNCATED AT 400 WORDS)

Effect of Riboflavin, Retinol, and Zinc on Micronuclei of Buccal Mucosa and of Esophagus: A Randomized Double-Blind Intervention Study in China

Abstract: A randomized double-blind intervention trial was done in Huixian, People's Republic of China, a population with a high incidence of esophageal cancer. The aim of the trial was to determine whether a once-a-week treatment with retinol (15 mg or 50,000 IU), riboflavin (200 mg), and zinc (50 mg) could result, after 1 year, in a lower prevalence of precancerous lesions of the esophagus in the group receiving the active treatment as compared with the prevalence in the group receiving a placebo. The results of the trial, published elsewhere, indicated that the treatment had no effect on the prevalence of precancerous lesions of the esophagus. In determining whether an effect could be detected when earlier end points are used, the prevalence of micronuclei was evaluated in exfoliated cells from the esophagus and from the buccal mucosa in the present study. In a subsample of 200 out of the original 610 study subjects, smears were taken from the buccal mucosa before and after treatment, and in 170 subjects esophageal smears were obtained during endoscopy only after treatment. The smears were fixed and kept at room temperature over 1 year before being evaluated for the presence of micronuclei by means of 4'-6-diamidino-2-phenylindole fluorescent staining. Smears from approximately half of the subjects were considered suitable for evaluation. No statistically significant difference in the prevalence of micronuclei in the buccal mucosa cells was observed before and after treatment (the mean percentage of micronucleated cells in the vitamin group upon first examination, before treatment started, 0.35%; 1 year after treatment, 0.31%) or between the treatment and the placebo group at the final examination. (The mean percentage of micronucleated cells in the vitamin-treated group was 0.31 and 0.39% in the placebo group.) However, a statistically significant reduction (P = .04) was observed in the prevalence of micronuclei in esophageal cells in the treatment group as compared to the placebo. (The mean percentage of micronucleated cells in the vitamin-treated group was 0.19%; it was 0.31% in the placebo group.

Hot maté drinking and precancerous lesions of the oesophagus: An endoscopic survey in southern brazil

Abstract: Thermal injury resulting from drinking very hot beverages has been incriminated as a risk factor for oesophageal cancer, although no information is available on the lesions caused by this injury in human or experimental animals. The drinking of hot mate tea is very common in areas of moderately high incidence of oesophageal cancer in south-eastern areas of South America. This study investigated the prevalence of precancerous lesions of the oesophagus in 60 unskilled male workers, of whom half were daily mate drinkers and the remainder were non-mate drinkers. These 2 groups were matched for age, smoking and alcohol intake. Mate drinkers were 2.2 times more likely (p = 0.046) to develop histologically confirmed oesophagitis than non-mate drinkers.

Paired Epstein-Barr virus (EBV)-negative and EBV-converted Burkitt lymphoma lines: stimulatory capacity in allogeneic mixed lymphocyte cultures

Abstract: Epstein-Barr virus (EBV)-negative Burkitt lymphoma lines (BLE-) and their in vitro EBV-converted sublines (BLEc), obtained by infection with the P3HRI and B95-8 strains of EBV, were compared for their capacity to induce T-lymphocyte proliferation in allogeneic mixed lymphocyte cultures (MLC). Regardless of the virus strain used for conversion, the BLEc lines induced a considerably stronger primary MLC response than their EBV-negative parentals. Only the BLEc lines were able to maintain T-lymphocyte proliferation in repeated stimulations. The low proliferative response observed in cultures stimulated with BLE- cells was not due to the generation of suppressor cells or to the release of inhibitory factors. The increased stimulatory capacity of BLEc lines was unrelated to changes in expression of MHC class-I and class-II antigen, or of B-cell activation markers, and was not due to the reactivation of EBV-specific memory T cells, since lymphocytes from EBV-seropositive and seronegative donors responded similarly. The results indicate that the capacity of BL cells to elicit cellular immune responses may be influenced by their EBV-carrying status.

Age curves of central nervous system tumor incidence in adults: variation of shape by histologic type.

Abstract: Data from nine population-based cancer registries from the National Cancer Institute's Surveillance, Epidemiology, and End Results program of the United States were used to study the incidence of individual histologic types of malignant central nervous system tumors by age and sex among adults. On a log-log scale, incidence increased linearly between the ages 35 and 64, with a slope that was not different between males and females or among registries but that varied by histologic type. The estimated slopes were 0.4 for ependymomas, 1.0 for oligodendrogliomas, 1.7 for astrocytomas, 2.8 for meningiomas, and 3.9 for glioblastomas. The rate at which incidence increased with age was significantly higher for glioblastomas than for other glial tumors. This finding suggests a different mechanism of carcinogenesis for glioblastomas than for other glial tumors.

Endogenous nitrosation in the oral cavity of chewers while chewing betel quid with or without tobacco.

Abstract: In order to evaluate endogenous nitrosation in the oral cavity of chewers of betel quid with tobacco (BQT) or without tobacco (BQ), saliva samples were collected from healthy male volunteers after chewing sequentially (i) unmodified BQT or BQ, (ii) BQT or BQ to which proline has been added, and (iii) BQT or BQ to which proline and ascorbic acid had been added. Samples were collected over 20 min and analysed for N-nitrosoproline (NPRO), tobacco-specific nitrosamines (TSNA) and areca nut-specific nitrosamines using gas chromatography-thermal energy analysis, arecoline and nicotine using gas chromatography-nitrogen phosphorus-specific detector, and for nitrite and thiocyanate. When results were expressed as a ratio of NPRO (ng/ml) to nicotine (micrograms/ml), all BQT chewers had increased NPRO contents after chewing BQT with proline. For BQ chewers, when the results were expressed as a ratio of NPRO (ng/ml) to arecoline (micrograms/ml), a similar increase in NPRO content was observed. However, the presence of ascorbic acid inhibited the increased nitrosation in only four out of ten BQT chewers and in five out of ten BQ chewers; in the rest of the samples, its presence enhanced the levels of NPRO. N'-Nitrosoanatabine (NAT) and N-nitrosoguvacoline (NGCO) levels decreased significantly in saliva of chewers of BQT in the presence of ascorbic acid, suggesting inhibition of their formation. In-vitro nitrosation of BQT/BQ with proline and proline plus ascorbic acid showed a similar pattern of nitrosation at salivary pH. The study confirmed previous results that certain nitrosamines are formed during the chewing of BQT/BQ.