Oxidative Stress, Inflammation, and Cancer: How Are They Linked?

Comprehensive identification and cataloging of copy number variations (CNVs) is required to provide a complete view of human genetic variation. The resolution of CNV detection in previous experimental designs has been limited to tens or hundreds of kilobases. Here we present PennCNV, a hidden Markov model (HMM) based approach, for kilobase-resolution detection of CNVs from Illumina high-density SNP genotyping data. This algorithm incorporates multiple sources of information, including total signal intensity and allelic intensity ratio at each SNP marker, the distance between neighboring SNPs, the allele frequency of SNPs, and the pedigree information where available. We applied PennCNV to genotyping data generated for 112 HapMap individuals; on average, we detected approximately 27 CNVs for each individual with a median size of approximately 12 kb. Excluding common rearrangements in lymphoblastoid cell lines, the fraction of CNVs in offspring not detected in parents (CNV-NDPs) was 3.3%. Our results demonstrate the feasibility of whole-genome fine-mapping of CNVs via high-density SNP genotyping.

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PennCNV: An integrated hidden Markov model designed for high-resolution copy number variation detection in whole-genome SNP genotyping data

Prostate-specific membrane antigen is a type II membrane protein with folate hydrolase activity produced by prostatic epithelium. The expression of this molecule has also been documented in extraprostatic tissues, including small bowel and brain. In the present study, an extensive immunohistochemical analysis was performed on a panel of well-characterized normal and malignant human tissues to further define the pattern of prostate-specific membrane antigen (PSMA) expression. Detectable PSMA levels were identified in prostatic epithelium, duodenal mucosa, and a subset of proximal renal tubules. A subpopulation of neuroendocrine cells in the colonic crypts also exhibited PSMA immunoreactivity. All other normal tissues, including cerebral cortex and cerebellum, had undetectable levels of PSMA. Thirty-three of 35 primary prostate adenocarcinomas and 7 of 8 lymph node metastases displayed tumor cell PSMA immunostaining. Eight of 18 prostate tumors metastatic to bone expressed PSMA. All of the other nonprostatic primary tumors studied had undetectable PSMA levels. However, intense staining was observed in endothelial cells of capillary vessels in peritumoral and endotumoral areas of certain malignancies, including 8 of 17 renal cell carcinomas, 7 of 13 transitional cell carcinomas, and 3 of 19 colon carcinomas. Extraprostatic PSMA expression appears to be highly restricted. Nevertheless, its diverse anatomical distribution implies a broader functional significance than previously suspected. The decrease in PSMA immunoreactivity noted in advanced prostate cancer suggests that expression of this molecule may be linked to the degree of tumor differentiation. The neoexpression of PSMA in endothelial cells of capillary beds in certain tumors may be related to tumor angiogenesis and suggests a potential mechanism for specific targeting of tumor neovasculature.

https://clincancerres.aacrjournals.org/content/clincanres/3/1/81.full.pdf

Prostate-specific membrane antigen expression in normal and malignant human tissues.

Progress toward understanding the biology of prostate cancer has been slow due to the few animal research models available to study the spectrum of this uniquely human disease. To develop an animal model for prostate cancer, several lines of transgenic mice were generated by using the prostate-specific rat probasin promoter to derive expression of the simian virus 40 large tumor antigen-coding region. Mice expressing high levels of the transgene display progressive forms of prostatic disease that histologically resemble human prostate cancer, ranging from mild intraepithelial hyperplasia to large multinodular malignant neoplasia. Prostate tumors have been detected specifically in the prostate as early as 10 weeks of age. Immunohistochemical analysis of tumor tissue has demonstrated that dorsolateral prostate-specific secretory proteins were confined to well-differentiated ductal epithelial cells adjacent to, or within, the poorly differentiated tumor mass. Prostate tumors in the mice also display elevated levels of nuclear p53 and a decreased heterogeneous pattern of androgen-receptor expression, as observed in advanced human prostate cancer. The establishment of breeding lines of transgenic mice that reproducibly develop prostate cancer provides an animal model system to study the molecular basis of transformation of normal prostatic cells and the factors influencing the progression to metastatic prostate cancer.

https://www.pnas.org/content/pnas/92/8/3439.full.pdf

Prostate cancer in a transgenic mouse.

Prostate cancer afflicts one man in nine over the age of 65 and represents the most frequently diagnosed cancer in American men (Coffey 1993). Early detection through serum testing for prostate specific antigen (PSA) and improved procedures for surgical intervention and radiation therapy have significantly reduced the number of fatalities; however, there is still no effective cure for men with advanced disease. Therefore, much research has been dedicated to identifying prognostic markers that distinguish indolent versus aggressive forms of prostate cancer. In contrast, significantly less research has been devoted to understanding the molecular mechanisms that underlie normal prostate growth and development or cancer initiation and progression. In this review, we address recent progress toward the central objectives of understanding parameters of normal versus abnormal prostatic development and of elucidating a molecular pathway for prostate cancer progression. We focus on key regulatory molecules that have been implicated by analysis of patterns of allelic loss in human prostate cancers and/or by reverse genetic approaches in the mouse.

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Molecular genetics of prostate cancer

Our laboratory has previously reported on the derivation of LNCaP cell sublines from LNCaP tumors maintained in castrated and intact athymic male mice. These LNCaP sublines differ from the parental line in tumorigenicity and androgen dependence. This paper demonstrates that one of these sublines acquired metastatic potential. When inoculated either s.c. or orthotopically, the C4-2 subline metastasized to the lymph node and bone with an incidence of 11-50%. Interestingly, the incidence of osseous metastasis was higher in castrated than in intact male hosts. We evaluated the chromosomal, immunohistochemical, and biochemical characteristics of the LNCaP sublines derived from C4-2 tumors that metastasized to the lymph node and bone. Cytogenetic analysis showed that all sublines were human and shared common marker chromosomes with the parental LNCaP cells. This experimental human prostate cancer model may permit, for the first time, the study of the molecular mechanisms underlying human prostate cancer metastasis.

https://cancerres.aacrjournals.org/content/canres/54/10/2577.full.pdf

Androgen-independent cancer progression and bone metastasis in the LNCaP model of human prostate cancer.

By using the newly developed adhesive tumor cell culture system, we analyzed the chromosomal constitutions of primary lung tumor and nonmalignant normal lung tissue from 10 previously untreated patients with non-small cell lung cancer. Chromosomal analyses were successfully carried out in banded chromosome preparations from 10 tumor and 8 normal lung tissue samples. All analyzed tumor and normal lung tissue samples had a predominantly normal diploid chromosome number. However, there was at least one structural or numerical alteration in every tumor and lung tissue sample analyzed. Chromosomes 1, 3, 4, 6, 7, 8, 9, 12, 15, and 20 were more often involved in rearrangement. The most consistent finding was trisomy 7; 4 patients had trisomy 7 in both tumor and normal lung tissue, and another 2 had this anomaly in tumor tissue only. Of the 4 patients without trisomy 7, 2 had a homogeneously staining region in the short arm of chromosome 7 in tumor tissue. Phytohemagglutinin-stimulated peripheral blood lymphocytes from 7 patients, including 5 patients with trisomy 7 in tumor tissue, did not show trisomy 7. These cytogenetic data suggest that chromosome 7 may be associated with lung cancer development and that trisomy 7 may be the hallmark of premalignant changes, at least in a subgroup of patients with non-small cell lung cancer.

https://cancerres.aacrjournals.org/content/canres/47/23/6349.full.pdf

Involvement of Chromosome 7 in Primary Lung Tumor and Nonmalignant Normal Lung Tissue

Chromosomal anomalies were analyzed in the lymphocyte cultures among 96 untreated lung cancer patients and 74 clinically normal comparison subjects. The analysis revealed that >15% of the lung cancer patients showed structural or numerical rearrangements in chromosomes 1,3,5,7,9,12,14, and 21. A case control comparison showed that these aberrations were significantly higher in chromosome 7 [odds ratio (OR) = 2.32; 95% confidence interval (CI), 1.14 and 4.82], chromosome 9 (OR = 2.61; 95% CI, 1.27 and 5.48), chromosome 12 (OR = 4.10; 95% CI, 1.40 and 14.54), and chromosome 21 (OR = 7.75; 95% CI, 1.73 and 70.80) of the patients than in the controls. However, only chromosome 9 (OR = 3.57; 95% CI, 1.33 and 9.46) and chromosome 21 (OR = 6.94; 95% CI, 3.15 and 9.98) retained significance after stratifying on smoking status. Among the lung cancer patients, the breakpoints cluster in specific regions of some of these chromosomes. These regions are 1p13-q21, 3q21-q13, 7p12-q12, 7q12-q12,7q22, 7q32, 9p13-q13, 12p13, 14q11, and 14q32. The distribution of lung cancer patients, according to histological types, showed that aberrations in chromosomes 1,7, and 9 dominated the scenario of chromosomal changes in non-small cell lung carcinomas. Thus, the data on lymphocytic chromosomal rearrangements in lung cancer patients not only indicate the importance of specific genetic changes in the etiology of lung cancer but also emphasizes the putative role of such analysis in determining primary genetic abnormalities in the large heterogeneous group of lung cancers.

https://cebp.aacrjournals.org/content/cebp/4/7/743.full.pdf

Genetic susceptibility to lung cancer as determined by lymphocytic chromosome analysis.

Constitutional chromosome abnormalities that may predispose a group of individuals to develop certain neoplasms have been reported for some human solid tumors. Deletions of 13q in retinoblastoma, 11p in Wilms' tumor, 1p in neuroblastoma, 3p in renal cell carcinoma, 5q in colorectal carcinoma and 22q in meningioma are examples of such anomalies. In breast carcinoma, a specific cytogenetic defect has not been conclusively identified. We have studied Phytohemagglutinin-stimulated lymphocytes of 76 breast cancer patients, 68 predisposed family members, 40 controls, and 30 additional controls with lung cancer to determine whether nonrandom chromosome defects are present. From each sample 100, G-or Q-banded metaphase spreads were studied for rearrangements. A marked clustering of alterations in the long arm of chromosome no. 1 (q11-22) was seen in breast cancer patients and in some predisposed family members. Alterations in 1q were present in 1% to 3% of metaphases, and included translocations to chromosomes 3, 6, 7, 9, 12, 15, 17, 18, 21 and the X; deletion of 1q, or pericentric inversion. Twelve out of 62 (19.3%) familial cases, 3 out of 14 (21.4%) sporadic cases, 9 out of 68 (13.2%) predisposed cases and 2 out of 40 (5%) control cases showed 1q alterations. None of the 30 lung cancer patients showed chromosome 1 anomaly in this region. This is consistent with the reports on primary breast tumor tissues, cell lines and pleural effusions where 1q defects have been reported. We conclude that chromosome 1q rearrangement might be one of the primary lesions specifically associated with the development of breast cancer.

Chromosome anomalies in human breast cancer: evidence for specific involvement of 1q region in lymphocyte cultures.

The purpose of this study was to measure DNA repair capacity and mutagen sensitivity in patients who have had three or more primary forms of cancer. It was hypothesized that, if abnormalities in DNA repair and mutagen sensitivity were cancer susceptibility factors, such findings would be seen with regularity in individuals with multiple primary cancers. DNA repair capacity was measured by determining repair of UV-irradiated plasmid DNA (pCMVCAT) transfected into peripheral blood lymphocytes. Results from 18 patients and a like number of age- and sex-matched controls demonstrated a significant difference in DNA repair capacity (P < 0.0001; odds ratio = 14). Mutagen sensitivity was measured by determining the mean number of chromatid breaks per cell after in vitro exposure to either bleomycin or 4-nitroquinoline-1-oxide. The difference in mean bleomycin- or 4-nitroquinoline-1-oxide-induced mutagen sensitivity between cases and controls was not statistically significant. Fourteen of the 18 patients had positive family histories of cancer; in 10, the history was compatible with cancer susceptibility syndromes. Although the numbers were small, there was no suggestion in this study that treatment or the presence of cancer was the cause of the DNA repair abnormalities encountered. These findings support the concept of diminished DNA repair capacity as an underlying feature in the development of a mutator phenotype.

https://cebp.aacrjournals.org/content/cebp/7/4/321.full.pdf

Vicki L. Hopwood

Papers

Androgen-independent cancer progression and bone metastasis in the LNCaP model of human prostate cancer.

Involvement of Chromosome 7 in Primary Lung Tumor and Nonmalignant Normal Lung Tissue

Genetic susceptibility to lung cancer as determined by lymphocytic chromosome analysis.

Chromosome anomalies in human breast cancer: evidence for specific involvement of 1q region in lymphocyte cultures.

Dna repair and mutagen sensitivity in patients with triple primary cancers