Xenobiotic-metabolizing gene variants, pesticide use, and the risk of prostate cancer.

BACKGROUND: To explore associations with prostate cancer and farming, it is important to investigate the relationship between pesticide use and single nucleotide polymorphisms (SNPs) in xenobiotic metabolic enzyme (XME) genes. OBJECTIVE: [corrected] We evaluated pesticide-SNP interactions between 45 pesticides and 1913 XME SNPs with respect to prostrate cancer among 776 cases and 1444 controls in the Agricultural Health Study. METHODS: We used unconditional logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs). Multiplicative SNP-pesticide interactions were calculated using a likelihood ratio test. RESULTS: A positive monotonic interaction was observed between petroleum oil/petroleum distillate use and rs1883633 in the oxidative stress gene glutamate cysteine ligase (GCLC; P interaction=1.0×10(-4)); men carrying at least one variant allele (minor allele) experienced an increased prostate cancer risk (OR=3.7, 95% CI: 1.9-7.3). Among men carrying the variant allele for thioredoxin reductase 2 (TXNRD2) rs4485648, microsomal epoxide hydrolase 1 (EPHX1) rs17309872, or myeloperoxidase (MPO) rs11079344, an increased prostate cancer risk was observed with high, compared with no, petroleum oil/petroleum distillate (OR=1.9, 95% CI: 1.1-3.2, P interaction=0.01; OR=2.1, 95% CI: 1.1-4.0, P interaction=0.01), or terbufos (OR=3.0, 95% CI: 1.5-6.0, P interaction=2.0×10(-3)) use, respectively. No interactions were deemed noteworthy at the false discovery rate=0.20 level; the number of observed interactions in XMEs was comparable with the number expected by chance alone. CONCLUSION: We observed several pesticide-SNP interactions in oxidative stress and phase I/II enzyme genes and risk of prostate cancer. Additional work is needed to explain the joint contribution of genetic variation in XMEs, pesticide use, and prostate cancer risk.

Vitamin D receptor polymorphisms and breast cancer risk: results from the National Cancer Institute Breast and Prostate Cancer Cohort Consortium.

BACKGROUND: Vitamin D is hypothesized to lower the risk of breast cancer by inhibiting cell proliferation via the nuclear vitamin D receptor (VDR). Two common single nucleotide polymorphisms (SNP) in the VDR gene (VDR), rs1544410 (BsmI), and rs2228570 (FokI), have been inconsistently associated with breast cancer risk. Increased risk has been reported for the FokI ff genotype, which encodes a less transcriptionally active isoform of VDR, and reduced risk has been reported for the BsmI BB genotype, a SNP in strong linkage disequilibrium with a 3'-untranslated region, which may influence VDR mRNA stability. METHODS: We pooled data from 6 prospective studies in the National Cancer Institute Breast and Prostate Cancer Cohort Consortium to examine associations between these SNPs and breast cancer among >6,300 cases and 8,100 controls for each SNP using conditional logistic regression. RESULTS: The odds ratio (OR) for the rs2228570 (FokI) ff versus FF genotype in the overall population was statistically significantly elevated [OR, 1.16; 95% confidence interval (95% CI), 1.04-1.28] but was weaker once data from the cohort with previously published positive findings were removed (OR, 1.10; 95% CI, 0.98-1.24). No association was noted between rs1544410 (BsmI) BB and breast cancer risk overall (OR, 0.98; 95% CI, 0.89-1.09), but the BB genotype was associated with a significantly lower risk of advanced breast cancer (OR, 0.74; 95% CI, 0.60-0.92). CONCLUSIONS: Although the evidence for independent contributions of these variants to breast cancer susceptibility remains equivocal, future large studies should integrate genetic variation in VDR with biomarkers of vitamin D status.

Genetic susceptibility loci, pesticide exposure and prostate cancer risk.

Uncovering SNP (single nucleotide polymorphisms)-environment interactions can generate new hypotheses about the function of poorly characterized genetic variants and environmental factors, like pesticides. We evaluated SNP-environment interactions between 30 confirmed prostate cancer susceptibility loci and 45 pesticides and prostate cancer risk in 776 cases and 1,444 controls in the Agricultural Health Study. We used unconditional logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs). Multiplicative SNP-pesticide interactions were calculated using a likelihood ratio test. After correction for multiple tests using the False Discovery Rate method, two interactions remained noteworthy. Among men carrying two T alleles at rs2710647 in EH domain binding protein 1 (EHBP1) SNP, the risk of prostate cancer in those with high malathion use was 3.43 times those with no use (95% CI: 1.44-8.15) (P-interaction= 0.003). Among men carrying two A alleles at rs7679673 in TET2, the risk of prostate cancer associated with high aldrin use was 3.67 times those with no use (95% CI: 1.43, 9.41) (P-interaction= 0.006). In contrast, associations were null for other genotypes. Although additional studies are needed and the exact mechanisms are unknown, this study suggests known genetic susceptibility loci may modify the risk between pesticide use and prostate cancer.

Pesticide exposure and inherited variants in vitamin d pathway genes in relation to prostate cancer.

BACKGROUND: Vitamin D and its metabolites are believed to impede carcinogenesis by stimulating cell differentiation, inhibiting cell proliferation, and inducing apoptosis. Certain pesticides have been shown to deregulate vitamin D's anticarcinogenic properties. We hypothesize that certain pesticides may be linked to prostate cancer via an interaction with vitamin D genetic variants. METHODS: We evaluated interactions between 41 pesticides and 152 single-nucleotide polymorphisms (SNP) in nine vitamin D pathway genes among 776 prostate cancer cases and 1,444 male controls in a nested case-control study of Caucasian pesticide applicators within the Agricultural Health Study. We assessed Pinteraction values using likelihood ratio tests from unconditional logistic regression and a false discovery rate (FDR) to account for multiple comparisons. RESULTS: Five significant interactions (P < 0.01) displayed a monotonic increase in prostate cancer risk with individual pesticide use in one genotype and no association in the other. These interactions involved parathion and terbufos use and three vitamin D genes (VDR, RXRB, and GC). The exposure-response pattern among participants with increasing parathion use with the homozygous CC genotype for GC rs7041 compared with unexposed participants was noteworthy [low vs. no exposure: OR, 2.58, 95% confidence interval (CI), 1.07-6.25; high vs. no exposure: OR, 3.09, 95% CI, 1.10-8.68; Pinteraction = 3.8 × 10(-3)]. CONCLUSIONS: In this study, genetic variations in vitamin D pathway genes, particularly GC rs7041, an SNP previously linked to lower circulating vitamin D levels, modified pesticide associations with prostate cancer risk. IMPACT: Because our study is the first to examine this relationship, additional studies are needed to rule out chance findings.

Genome-wide association study identifies multiple risk loci for chronic lymphocytic leukemia.

Genome-wide association studies (GWAS) have previously identified 13 loci associated with risk of chronic lymphocytic leukemia or small lymphocytic lymphoma (CLL). To identify additional CLL susceptibility loci, we conducted the largest meta-analysis for CLL thus far, including four GWAS with a total of 3,100 individuals with CLL (cases) and 7,667 controls. In the meta-analysis, we identified ten independent associated SNPs in nine new loci at 10q23.31 (ACTA2 or FAS (ACTA2/FAS), P=1.22×10(-14)), 18q21.33 (BCL2, P=7.76×10(-11)), 11p15.5 (C11orf21, P=2.15×10(-10)), 4q25 (LEF1, P=4.24×10(-10)), 2q33.1 (CASP10 or CASP8 (CASP10/CASP8), P=2.50×10(-9)), 9p21.3 (CDKN2B-AS1, P=1.27×10(-8)), 18q21.32 (PMAIP1, P=2.51×10(-8)), 15q15.1 (BMF, P=2.71×10(-10)) and 2p22.2 (QPCT, P=1.68×10(-8)), as well as an independent signal at an established locus (2q13, ACOXL, P=2.08×10(-18)). We also found evidence for two additional promising loci below genome-wide significance at 8q22.3 (ODF1, P=5.40×10(-8)) and 5p15.33 (TERT, P=1.92×10(-7)). Although further studies are required, the proximity of several of these loci to genes involved in apoptosis suggests a plausible underlying biological mechanism.

The Interaction between Pesticide Use and Genetic Variants Involved in Lipid Metabolism on Prostate Cancer Risk.

Background. Lipid metabolism processes have been implicated in prostate carcinogenesis. Since several pesticides are lipophilic or are metabolized via lipid-related mechanisms, they may interact with variants of genes in the lipid metabolism pathway. Methods. In a nested case-control study of 776 cases and 1444 controls from the Agricultural Health Study (AHS), a prospective cohort study of pesticide applicators, we examined the interactions between 39 pesticides (none, low, and high exposure) and 220 single nucleotide polymorphisms (SNPs) in 59 genes. The false discovery rate (FDR) was used to account for multiple comparisons. Results. We found 17 interactions that displayed a significant monotonic increase in prostate cancer risk with pesticide exposure in one genotype and no significant association in the other genotype. The most noteworthy association was for ALOXE3 rs3027208 and terbufos, such that men carrying the T allele who were low users had an OR of 1.86 (95% CI = 1.16-2.99) and high users an OR of 2.00 (95% CI = 1.28-3.15) compared to those with no use of terbufos, while men carrying the CC genotype did not exhibit a significant association. Conclusion. Genetic variation in lipid metabolism genes may modify pesticide associations with prostate cancer; however our results require replication.

Genome-wide association analysis identifies new lung cancer susceptibility loci in never-smoking women in Asia.

To identify common genetic variants that contribute to lung cancer susceptibility, we conducted a multistage genome-wide association study of lung cancer in Asian women who never smoked. We scanned 5,510 never-smoking female lung cancer cases and 4,544 controls drawn from 14 studies from mainland China, South Korea, Japan, Singapore, Taiwan and Hong Kong. We genotyped the most promising variants (associated at P < 5 × 10(-6)) in an additional 1,099 cases and 2,913 controls. We identified three new susceptibility loci at 10q25.2 (rs7086803, P = 3.54 × 10(-18)), 6q22.2 (rs9387478, P = 4.14 × 10(-10)) and 6p21.32 (rs2395185, P = 9.51 × 10(-9)). We also confirmed associations reported for loci at 5p15.33 and 3q28 and a recently reported finding at 17q24.3. We observed no evidence of association for lung cancer at 15q25 in never-smoking women in Asia, providing strong evidence that this locus is not associated with lung cancer independent of smoking.

Pesticide use modifies the association between genetic variants on chromosome 8q24 and prostate cancer.

Genome-wide association studies have identified 8q24 region variants as risk factors for prostate cancer. In the Agricultural Health Study, a prospective study of licensed pesticide applicators, we observed increased prostate cancer risk with specific pesticide use among those with a family history of prostate cancer. Thus, we evaluated the interaction among pesticide use, 8q24 variants, and prostate cancer risk. The authors estimated odds ratios (OR) and 95% confidence intervals (95% CI) for interactions among 211 8q24 variants, 49 pesticides, and prostate cancer risk in 776 cases and 1,444 controls. The ORs for a previously identified variant, rs4242382, and prostate cancer increased significantly (P<0.05) with exposure to the organophosphate insecticide fonofos, after correction for multiple testing, with per allele ORnonexposed of 1.17 (95% CI, 0.93-1.48), per allele OR(low) of 1.30 (95% CI, 0.75-2.27), and per allele ORhigh of 4.46 (95% CI, 2.17-9.17; P-interaction=0.002, adjusted P-interaction=0.02). A similar effect modification was observed for three other organophosphate insecticides (coumaphos, terbufos, and phorate) and one pyrethroid insecticide (permethrin). Among ever users of fonofos, subjects with three or four risk alleles at rs7837328 and rs4242382 had approximately three times the risk of prostate cancer (OR, 3.14; 95% CI, 1.41-7.00) compared with subjects who had zero risk alleles and never used fonofos. We observed a significant interaction among variants on chromosome 8q24, pesticide use, and risk of prostate cancer. Insecticides, particularly organophosphates, were the strongest modifiers of risk, although the biological mechanism is unclear. This is the first report of effect modification between 8q24 and an environmental exposure on prostate cancer risk.

Condom use and vaginal Y-chromosome detection: the specificity of a potential biomarker.

OBJECTIVE: Detection of vaginal Y-chromosome sequences (YCS) may be a useful biomarker to validate sexual behavior reporting in women. We describe the effects of condom use on the detection of vaginal YCS. METHODS: Fifty-six women were asked to abstain from sexual intercourse for 14 days. On day 15, participants were asked to engage in sexual intercourse with their male partners using condoms. Self-collected vaginal swabs were obtained on days 14, 16, and 17. YCS were detected using the Roche LightCycler with the use of positive controls. RESULTS: Fourty-four of 56 women completed the study. Five women (11.4%) had detectable YCS. The overall specificity of the YCS assay with condom use was 92% (95% CI: 80%-98%). Although women who reported receptive oral sex and digital penetration within 48 hours of swab collection had a higher detection rate of YCS [RR 2.3 (95% CI: 1.1-4.6) and 3.6 (95%CI: 1.6-8.5), respectively], the mean concentration of YCS was much less than that associated with unprotected vaginal intercourse (P <0.001) CONCLUSIONS: Condom use during intercourse appears to prevent vaginal YCS detection; this may be a useful biomarker to validate self-reported condom use.

Polymerase chain reaction detection of Y-chromosome sequences in vaginal fluid of women accessing a sexually transmitted disease clinic.

BACKGROUND: Reporting bias and validity estimation of self-reports in clinical settings is a major problem in sexual behavior research. OBJECTIVE: The objective of this study was to determine if a newly described biomarker tool helps clarify sensitivity issues related to condom use self-report. METHODS: A polymerase chain reaction (PCR) assay to detect Y-chromosome (Yc) fragments was used to assess detectability and longevity of YcDNA in vaginal swabs collected from 141 women seeking care for sexually transmitted disease (STD)-related symptoms or as a reported sexual contact to STD. Data analyzed were collected in 1992 to 1994 as part of the Transmission, Acquisition, and Condom Use study. Archived vaginal swab samples were selected from women who in the accompanying survey reported their last intercourse in the previous 14 days. Survey data about partners, sexual behaviors, and self-reported condom use in the previous month was also retrieved. RESULTS: Overall, 137 (97.2%) vaginal samples had usable PCR assay results; 90 (65.7%) had detectable YcDNA content. Linear regression showed that number of days since last sexual intercourse was a significant predictor of YcDNA concentration. PCR results were compared with self-reported condom use. Of the women, 67 (47.5%) women reported no condom use in the last 14 days, and 36 (25.5%) women reported using condoms consistently. Although YcDNA was detected in the swabs of both condom reporting groups, mean DNA content was significantly lower among the consistent condom users. CONCLUSION: The YcPCR assay can detect DNA in a clinical sample of women for up to two weeks. This assay may be useful as a qualitative adjunct to behavioral studies to further understanding of sexual behavior reporting in women.

Polymerase chain reaction detection of Y chromosome sequences in vaginal fluid: preliminary studies of a potential biomarker for sexual behavior.

BACKGROUND: Self-reported measures of sexual behavior are subject to nontrivial reporting biases. OBJECTIVE: The objective of this study was to develop a behavioral biomarker of recent sexual activity among females that is inexpensive, easily administered, and can be used in low sexually transmitted disease prevalence populations. METHODS: We developed a polymerase chain reaction (PCR) assay to detect Y chromosome (Yc) fragments. The Yc primers were developed against a 200-basepair (bp) microsatellite repeat sequence, which is unique to the male genome. A standard PCR technique was used. Assay sensitivity was determined quantitatively using donated semen samples. To assess longevity of detectability, we recruited female subjects in monogamous relationships. Seventeen subjects had unprotected intercourse followed by 3 weeks of abstinence from vaginal intercourse. Self-administered vaginal swabs (SAVS) were collected every other day. In addition to the swabs, subjects kept daily sexual diaries. Swabs were processed by semiquantitative PCR, and Yc decay curves were determined for each subject. The half-life of Yc in vaginal fluid was calculated on the collection of individual decay curves by a random-effects regression model approach. RESULTS: The sensitivity of our Yc-PCR assay was determined to be 5 copies of Yc. In the longevity studies, Yc was detectable in SAVS up to 15 postcoital days (PCD). Mean Yc DNA concentration in SAVS eluate followed an exponential decay pattern for each subject. Mean concentrations were 66.7 ng/mL at PCD-1, 20.6 ng/mL at PCD-7, and 4.5 ng/mL at PCD-15. The estimated half-life for Yc clearance was 3.83 days. CONCLUSION: The swab-based Yc-DNA PCR assay can detect coitus in women for a 2-week retrospective period. This can be used to validate sexual behavior-reporting and condom use in women and promises to be a useful tool in sexual behavior research.

Use of applied biosystems 7900HT sequence detection system and Taqman assay for detection of quinolone-resistant Neisseria gonorrhoeae.

Mutations in quinolone resistance-determining regions (QRDRs) have been associated with quinolone-resistant Neisseria gonorrhoeae (QRNG). Since diagnostic nucleic acid amplification tests for gonococci are now in frequent use, molecular detection of QRNG could facilitate surveillance in the absence of culture. Here we describe a real-time molecular assay for detecting QRDR mutations in gonococci.

Quinolone resistance-determining region mutations and por type of Neisseria gonorrhoeae isolates: resistance surveillance and typing by molecular methodologies.

Quinolone resistance is increasing rapidly in Neisseria gonorrhoeae and is a significant public health problem that requires ongoing surveillance. To examine the feasibility of molecular surveillance of quinolone resistance, and to further characterize an outbreak of resistant N. gonorrhoeae in Israel, the quinolone resistance-determining region (QRDR) sequences and the por types of 80 N. gonorrhoeae isolates were determined using molecular techniques. QRDRs of gyrA and parC were amplified by polymerase chain reaction and were sequenced directly. The por type was determined by checkerboard hybridizations performed using oligonucleotide probes to regions encoding 5 variable loops of the porin protein. All 42 ciprofloxacin-resistant (CipR) isolates had mutations in QRDRs of both gyrA and parC, and identical mutations were found in 93% of these isolates. One intermediately resistant isolate had 1 mutation in gyrA, and susceptible isolates showed no mutations. Forty isolates had 1 of 2 por types that differed only by an in-frame deletion in variable region 5; all but 1 of these isolates were CipR. QRDR sequencing and por type determination showed that the outbreak of CipR N. gonorrhoeae in Israel was clonal. QRDR mutations were consistent with those previously characterized; this indicates that DNA probes can be developed for rapid detection and surveillance of quinolone-resistant N. gonorrhoeae in settings in which nonculture diagnostic methods are used.

Analysis of vaginal acetic acid in patients undergoing treatment for bacterial vaginosis.

A "gold standard" method for the diagnosis of bacterial vaginosis (BV) is lacking. The clinical criteria described by the Amsel technique are subjective and difficult to quantify. Alternatively, the reading of Gram-stained vaginal smears by scoring techniques such as those that use the Nugent or Hay-Ison scoring systems is again subjective, requires expert personnel to perform the reading, and is infrequently used clinically. Recently, a new diagnostic device, the Osmetech Microbial Analyzer--Bacterial Vaginosis (OMA-BV), which determines a patient's BV status on the basis of measurement of the amount of acetic acid present in a vaginal swab specimen, was approved by the Food and Drug Administration. The present study uses the conducting polymer gas-sensing technology of OMA-BV to measure the concentration of acetic acid in the headspace above vaginal swab specimens from patients undergoing treatment for BV with metronidazole. In 97.8% of the cases the level of acetic acid detected fell sharply during the treatment period, crossing from above to below the diagnostic threshold of 900 ppm. The diagnosis obtained on the basis of the level of vaginal acetic acid was compared with the diagnoses obtained by use of the Amsel criteria and the Nugent scoring system both at the time of initial entry into the study and at the repeat samplings on days 7 and 14. The results obtained with OMA-BV showed overall agreements compared with the results of the Amsel and Nugent tests of 98 and 94%, respectively, for the 34 patients monitored through the treatment process. This provides further evidence that the measurement of vaginal acetic acid by headspace analysis with conducting polymer sensors is a valid alternative to present tests for the diagnosis of BV.