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Human skin xenografts were established on the subscapular area of skin of nude (nu/nu NIH-Swiss background) mice. When treated with benzo[a]pyrene diol epoxide I (BPDE I), specific carcinogen-DNA adducts were formed. Separation and identification of these adducts by the 32P-postlabeling technique indicated that the 7R- and 7S-BPDE I-dpGp adducts were the major adducts. Xenografts pretreated with either allantoin of anthralin showed an increase in the major 7R- and 7S-BPDE I adducts compared to only BPDE I treatment. Likewise, we observed an increase in the quantity of different minor adducts. The ratios between the minor and major adducts in the pretreated grafts remained consistent with the ratio in the grafts treated with BPDE I only. We conclude that these modulators induce cells in the xenograft to enter S phase of the cell cycle. Moreover, we observed that these compounds altered the quantity of the minor carcinogen-DNA adducts without altering the overall ratios between the major 7R- and 7S-BPDE I-dpGp adducts and the minor carcinogen-DNA adducts. [ABSTRACT FROM AUTHOR]

Previous studies have suggested that lead exposure may be associated with increased risk of amyotrophic lateral sclerosis (ALS). Polymorphisms in the genes for δ-aminolevulinic acid dehydratase (ALAD) and the vitamin D receptor (VDR) may affect susceptibility to lead exposure. We used data from a case-control study conducted in New England from 1993 to 1996 to evaluate the relationship of ALS to polymorphisms in ALAD and VDR and the effect of these polymorphisms on the association of ALS with lead exposure. The ALAD 2 allele (177G to C; K59N) was associated with decreased lead levels in both patella and tibia, although not in blood, and with an imprecise increase in ALS risk [odds ratio (OR) = 1.9; 95% confidence interval (95% CI), 0.60-6.3]. We found a previously unreported polymorphism in ALAD at an Msp1 site in intron 2 (IVS2+299G>A) that was associated with decreased bone lead levels and with an imprecise decrease in ALS risk (OR = 0.35; 95% CI, 0.10-1.2). The VDR B allele was not associated with lead levels or ALS risk Our ability to observe effects of genotype on associations of ALS with occupational exposure to lead or with blood or bone lead levels was limited. These findings suggest that genetic susceptibility conferred by polymorphisms in ALAD may affect ALS risk, possibly through a mechanism related to internal lead exposure. [ABSTRACT FROM AUTHOR]

Purpose: There is accumulating evidence that oxidative stress is an important contributor to carcinogenesis. We hypothesized that genetic variation in genes involved in maintaining antioxidant/oxidant balance would be associated with overall oxidative stress. Methods: We examined associations between single nucleotide polymorphisms (SNPs) in MnSOD, GSTP1, GSTM1, GPX1, GPX3, and CAT genes and thiobarbituric acid-reactive substances (TBARS), a blood biomarker of oxidative damage, in healthy white women randomly selected from Western New York (n = 1402). We used general linear models to calculate age-adjusted geometric means of TBARS across the variants. We also examined the associations within strata of menopausal status. Results: For MnSOD, being heterozygous was associated with lower geometric means of TBARS (less oxidative stress), 1.28 mg/dL, compared to homozygous T-allele or homozygous C-allele,1.35 mg/dL, and 1.31 mg/dL correspondingly (p for trend = 0.01). This difference remained among postmenopausal women, 1.40 mg/dL for TT, 1.32 mg/dL for TC, and 1.34mg/dL for CC (p for trend 0.015); it was attenuated among premenopausal women. SNPs in the other genes examined (GSTP1, GSTM1, GPX1, GPX3, and CAT) were not associated with TBARS. Conclusions: Our findings suggest that genetic variation in MnSOD gene may be associated with oxidative status, particularly among postmenopausal women. [ABSTRACT FROM AUTHOR]

Epstein-Barr virus (EBV) is associated with roughly 10% of gastric carcinomas worldwide (EBVaGC). Although previous investigations provide a strong link between EBV and gastric carcinomas, these studies were performed using selected EBV gene probes. Using a cohort of gastric carcinoma RNA-seq data sets from The Cancer Genome Atlas (TCGA), we performed a quantitative and global assessment of EBV gene expression in gastric carcinomas and assessed EBV associated cellular pathway alterations. EBV transcripts were detected in 17% of samples but these samples varied significantly in EBV coverage depth. In four samples with the highest EBV coverage (hiEBVaGC – high EBV associated gastric carcinoma), transcripts from the BamHI A region comprised the majority of EBV reads. Expression of LMP2, and to a lesser extent, LMP1 were also observed as was evidence of abortive lytic replication. Analysis of cellular gene expression indicated significant immune cell infiltration and a predominant IFNG response in samples expressing high levels of EBV transcripts relative to samples expressing low or no EBV transcripts. Despite the apparent immune cell infiltration, high levels of the cytotoxic T-cell (CTL) and natural killer (NK) cell inhibitor, IDO1, was observed in the hiEBVaGCs samples suggesting an active tolerance inducing pathway in this subgroup. These results were confirmed in a separate cohort of 21 Vietnamese gastric carcinoma samples using qRT-PCR and on tissue samples using in situ hybridization and immunohistochemistry. Lastly, a panel of tumor suppressors and candidate oncogenes were expressed at lower levels in hiEBVaGC versus EBV-low and EBV-negative gastric cancers suggesting the direct regulation of tumor pathways by EBV. [ABSTRACT FROM AUTHOR]

Base excision repair (BER) and nucleotide excision repair (NER) pathways repair damaged DNA, and polymorphisms in these genes might affect breast cancer susceptibility. We evaluated associations between seven single-nucleotide polymorphisms in four DNA repair genes (ERCC4 rs1799801, XPC rs2227998, rs2228001, rs2228000, OGG1 rs1052133 and XRCC1 rs25487 and rs25486) and breast cancer risk, examining modification by smoking and alcohol consumption, using data from the Western New York Exposures and Breast Cancer Study. Women aged 35–79 years with incident breast cancer (n = 1170) and age- and race-matched controls (n = 2115) were enrolled. Genotyping was performed using matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Unconditional logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CIs). No significant associations were observed in premenopausal women. Among postmenopausal women, rs25487 and rs25486 (OR = 1.24; 95% CI 1.01–1.51 and OR = 1.23; 95% CI 1.01–1.49, respectively, for combined heterozygous and homozygous variant compared with reference) were associated with increased risk of breast cancer. Postmenopausal women carrying the variant allele of the synonymous XPC polymorphism (rs2227998) were also at borderline significantly increased risk (OR = 1.24; 95% CI 1.01–1.52, heterozygous variant compared with reference; OR = 1.22; 95% CI 1.01–1.48, for combined heterozygous and homozygous variant compared with reference). There was no evidence of genotype–smoking and genotype–alcohol consumption interactions for pre- and postmenopausal women. These results indicate that some of the variants in BER and NER genes may influence risk of postmenopausal breast cancer. [ABSTRACT FROM AUTHOR]

Objectives: Deoxyribonucleic acid (DNA) extraction from blood and genotyping for candidate single nucleotide polymorphisms (SNP) is now an important part of almost all molecular epidemiologic studies. However, in many studies the amount of blood sample is limited or only serum is available. We conducted several pilot studies to identify methods for DNA extraction and high-throughput SNP genotyping of both white blood cell (WBC) and serum DNA that can be done centrally and reliably for large numbers of samples. Methods: We used biospecimens from the Prostate Cancer Prevention Trial (PCPT), a phase III, double-blind, placebo-controlled trial that tested the efficacy of finasteride for the primary prevention of prostate cancer. DNA was extracted from WBCs, from serum, and also from serum after organic solvent extraction for analysis of hormones. We also conducted blinded high-throughput genotyping in three laboratories to assess feasibility and reliability of results with differing methodologies using DNA from WBCs and from serum. Results: Genotyping of DNA extracted from WBCs resulted in highly reliable, reproducible results across laboratories using different genotyping platforms. However, genotyping with DNA extracted from serum did not provide reliable data using high-throughput multiplex approaches such as Sequenom (hME and iPLEX) and Applied Biosystems SNPlex, but was successful using Taqman. Conclusions: Based on the results of these pilot studies, we conclude that DNA obtained from serum must be used judiciously, and that genotyping using multiplex methods is not suitable for serum DNA. [Copyright &y& Elsevier]

Vascular endothelial growth factor(VEGF)is a cytokine essential for angiogenesis. A recent study found that haplotypes, determined by three SNPs(  -  2,578C/A,  -  1,154 G/A, and  -  634G/C)in theVEGFupstream promoter/leader sequence, were associated with risk of amyotrophic lateral sclerosis(ALS). We used samples and data from a case-control study to examine the relation of ALS toVEGFhaplotype. Genotypes at each of the three polymorphic sites were determined using allele-specific primer extension reactions followed by MALDI-TOF. We found a 3-fold increased risk among individuals homozygous for the AAG or AGG haplotypes(95%CI  =  0.7  -  13.4), consistent with the findings of the previous study. Given the wide confidence interval, our findings should be interpreted cautiously. [ABSTRACT FROM AUTHOR]

The mouse monoclonal antibody OSU 22-3 was prepared using cells from a squamous cell carcinoma (SCC) as an immunogen. This antibody reacts with an antigen found on squamous cell carcinomas but does not react with normal keratinocytes. This antibody and two antibodies that react with normal keratinocytes were used as markers of malignant and normal phenotypes. These markers were used to evaluate several spontaneous and carcinogen initiated SCC tumors and to identify the expression of an antigen associated with a malignant phenotype. A variety of subpopulations in carcinogen initiated tumors and spontaneous SCC tumors were noted. The subpopulations that reacted only with MoAb OSU 22-3 exhibited features of anchorage independent growth and cellular invasiveness, and formed progressively growing tumors in nude mice. Other SCC spontaneous tumor cell subpopulations reacted with the antibodies associated with normal keratinocytes. These cells did not proliferate in vitro and did not form tumors in the nude mouse. There were other carcinogen transformed cells which reacted with MoAb OSU 22-3 but not with the antibodies associated with normal keratinocytes. These cells exhibited anchorage independent growth and cellular invasiveness but did not form tumors in nude mice. We conclude from this work that human SCC tumors contain multiple cell populations. These cell populations have varied growth properties and express surface antigens that may indicate their malignant vigor. Carcinogen transformed keratinocytes do exhibit some of the characteristics of SCC tumor phenotypes but not the property of malignant progressively growing cells on a routine and consistent basis. This feature is transiently and inconsistently expressed in a surrogate host by populations prepared from spontaneous SSC tumors. [ABSTRACT FROM AUTHOR]