Prospective study of cytomegalovirus serostatus and prostate cancer risk in the Prostate Cancer Prevention Trial

PURPOSE

To investigate serologic evidence of infection by cytomegalovirus (CMV), a herpesvirus with known oncogenic potential that has been detected in malignant prostate tissue, in relation to prostate cancer (PCa) risk in a large case-control study nested in the Prostate Cancer Prevention Trial (PCPT).

METHODS

Cases were men with a confirmed diagnosis of PCa after visit 2 (n = 614), and controls were men not diagnosed with PCa during the trial who also had a negative end-of-study biopsy (n = 616). Controls were frequency-matched to cases by age, treatment arm, and family history of PCa. Sera from visit 2 were tested for CMV IgG antibodies.

RESULTS

No association was observed between CMV serostatus and PCa risk (adjusted CMV seroprevalence = 67.9 % for cases and 65.2 % for controls, odds ratio = 1.13, 95 % CI 0.89-1.45).

CONCLUSIONS

Considering our null findings in the context of the full CMV literature, CMV infection, as measured by serostatus, does not appear to increase PCa risk.

Polymorphisms in fragile histidine triad gene (FHIT) associated with aggressive prostate cancer and cancer specific mortality

4646

Background: FHIT is a 1.5 Mb gene encoding a 16.8 kD triphosphatase known to promote apoptosis responding to DNA damage in epithelial cells. It resides in the most frequently observed fragile site in the human genome, FRA3B, and is frequently deleted in early development of multiple cancer types. More importantly, down regulation of FHIT protein has been associated with clinical features of tumors, such as the presence of extraprostatic extension and Gleason Score > 8 in prostate cancer (CaP), advanced diseases in breast cancer, and shorter survival after platinum-based treatment for advanced non-small cell lung cancer. Previously, a genetic locus for CaP has been reported in FHIT. Here we evaluated association of aggressive CaP and death due to CaP with Single nucleotide polymorphisms (SNPs) in FHIT using cases and controls of European origin nested in the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening trial with 13 years of follow-up. Methods: We analyzed 659 SNPs on FHIT in 1,164 CaP patients (476 with nonaggressive CaP, Gleason < 7 and stage < III; 688 with aggressive CaP, Gleason >= 7 and/or stage III/IV; 63 with death due to CaP) and 1,167 controls using an incidence density sampling strategy. Stratified Cochran-Mantel-Haenszel test and logistic regression were performed to test association. Results: We detected significant association (p < 0.05) of incident CaP to 48 SNPs and aggressive CaP to 52 SNPs. After 50,000 permutations, two SNPs within a 7 kb region, one for incident CaP and the other for aggressive CaP, remained marginally significant (corrected p = 0.053 and 0.093, respectively). The same risk allele for aggressive CaP was also associated with CaP-specific mortality (OR = 1.50, p = 0.027). The association was stronger after adjusting for Gleason, stage, and PSA at diagnosis, treatment options after diagnosis. Test on imputed SNPs within the 7 kb intronic region identified 7 additional SNPs in 2 linkage disequilibrium groups at higher risk to CaP-specific death (OR = 1.98, p = 0.00015 and OR = 2.51, p = 0.0027). Conclusions: Risk SNPs in FHIT were implicated for aggressive disease and CaP specific death. Replication of these SNPs in other populations is warranted.

Interactions between genome-wide significant genetic variants and circulating concentrations of insulin-like growth factor 1, sex hormones, and binding proteins in relation to prostate cancer risk in the National Cancer Institute Breast and Prostate Cancer Cohort Consortium

Genome-wide association studies (GWAS) have identified many single nucleotide polymorphisms (SNPs) associated with prostate cancer risk. There is limited information on the mechanistic basis of these associations, particularly about whether they interact with circulating concentrations of growth factors and sex hormones, which may be important in prostate cancer etiology. Using conditional logistic regression, the authors compared per-allele odds ratios for prostate cancer for 39 GWAS-identified SNPs across thirds (tertile groups) of circulating concentrations of insulin-like growth factor 1 (IGF-1), insulin-like growth factor binding protein 3 (IGFBP-3), testosterone, androstenedione, androstanediol glucuronide, estradiol, and sex hormone-binding globulin (SHBG) for 3,043 cases and 3,478 controls in the Breast and Prostate Cancer Cohort Consortium. After allowing for multiple testing, none of the SNPs examined were significantly associated with growth factor or hormone concentrations, and the SNP-prostate cancer associations did not differ by these concentrations, although 4 interactions were marginally significant (MSMB-rs10993994 with androstenedione (uncorrected P = 0.008); CTBP2-rs4962416 with IGFBP-3 (uncorrected P = 0.003); 11q13.2-rs12418451 with IGF-1 (uncorrected P = 0.006); and 11q13.2-rs10896449 with SHBG (uncorrected P = 0.005)). The authors found no strong evidence that associations between GWAS-identified SNPs and prostate cancer are modified by circulating concentrations of IGF-1, sex hormones, or their major binding proteins.

Abstract 2599: IGF gene pathway and progression to fatal prostate cancer after diagnosis in men of European ancestry

Background: Substantial epidemiologic and experimental evidence implicated the role of insulin-like growth factor (IGF) pathway in prostate carcinogenesis. Many studies have demonstrated an increased risk of prostate cancer, especially advanced diseases among men with elevated IGF-I blood levels. Given limited evidence on the role of genetic variations in the IGF pathway on prostate cancer progression to fatal outcome, we comprehensively evaluated the association between genetic variants in 26 genes related to the insulin-like growth factor (IGF) pathway and prostate cancer specific mortality. Methods: Within the 7 cohort studies in the NCI Breast and Prostate Cancer Cohort Consortium (BPC3), a total of 590 tagging SNPs were successfully genotyped in 5887 men of European ancestry who were diagnosed with prostate cancer. SNPs were analyzed using Cox proportional hazards models under genotypic and additive allele models. Follow-up was defined from the date of prostate cancer diagnosis to the date of any death or last follow-up. Patients died from causes other than prostate cancer were censored. All analyses were adjusted for age at diagnosis and cohort. To account for multiple testing, the number of effective SNPs was calculated for each gene using a Spectral Decomposition approach. Results: In total, 704 prostate cancer deaths occurred during a median follow up of 8.9 years. After adjusting for age at diagnosis, cohorts and a gene-based correction for multiple testing, 3 SNPs in IGF2AS (insulin-like growth factor 2 antisense located in chromosome 11p15.5) were significantly associated with prostate cancer-specific mortality. Two of these SNPs (rs1004446 and rs3741211) were in linkage disequilibrium (r2=1) but they were not in linkage disequilibrium with the third SNP (rs4366464, r2=0.03). For rs3741211, each additional minor allele G was associated with 16% (HR 0.83; 95% CI 0.72-0.92; Pcorrected=0.02) lower risk of prostate cancer specific mortality. For rs4366464, each additional minor allele G was associated with 44% (HR 1.44; 95% CI 1.19-1.73) increased risk (Pcorrected=0.001). The association for SNP rs4366464 remained statistically significant after further adjusting for multiple testing on the 26 genes in the pathway. Conclusion: Germline variation in the IGF2AS gene was significantly positively and inversely associated with progression to fatal prostate cancer after diagnosis in this large cohort consortium of prostate cancer. These findings need to be confirmed by other studies. Given the link of this region in IGF2 imprinting, methylation and Wilms’ tumors, the role of IGF2AS in cancer progression deserves attention.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2599. doi:1538-7445.AM2012-2599

Abstract 3974: A comprehensive resequence-analysis of 250kb region of 8q24 in Africans

To date, genome-wide association studies (GWAS) have identified more than 45 prostate cancer susceptibility variants, of which at least 5 independent loci were identified within a 654kb region on 8q24. This region also harbors additional loci associated with cancers of the breast, colon, bladder, and chronic lymphocytic leukemia. Previously, the linkage disequilibrium (LD) pattern and recombination hotspots (chr8:128050768-128300801, hg19) defined a 250kb span (region 2) harboring multiple prostate cancer susceptibility loci identified in multiple distinct populations, as well as a locus rs2456449 associated with chronic lymphocytic leukemia in Europeans. Because GWAS identify genetic markers, fine-mapping using sequence analysis in diverse populations is necessary for defining the optimal variants for biological follow-up. Sequence analysis in populations of distinct ancestry can provide important insights into the differences of LD patterns and thus narrow down high interest variants. In the present study, we have resequenced the region in 125 men of African ancestry, which included 78 individuals from a population-based study in Ghana and 47 African-American individuals from the Johns Hopkins Hospital. Upon comparison with 1000 Genomes data (Oct 2011 release), we have identified 365 novel loci and additional surrogates of known susceptibility loci which could be important in establishing priorities for future functional work, designed to explain the biological basis of the association signal for both prostate cancer and perhaps, chronic lymphocytic leukemia.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3974. doi:1538-7445.AM2012-3974

Predictive performance of prostate cancer risk in Chinese men using 33 reported prostate cancer risk-associated SNPs

BACKGROUND

Genome-wide association studies (GWAS) have identified more than 30 single nucleotide polymorphisms (SNPs) that were reproducibly associated with prostate cancer (PCa) risk in populations of European descent. In aggregate, these variants have shown potential to predict risk for PCa in European men. However, their utility for PCa risk prediction in Chinese men is unknown.

METHODS

We selected 33 PCa risk-related SNPs that were originally identified in populations of European descent. Genetic scores were estimated for subjects in a Chinese case-control study (1,108 cases and 1,525 controls) based on these SNPs. To assess the performance of the genetic score on its ability to predict risk for PCa, we calculated area under the curve (AUC) of the receiver operating characteristic (ROC) in combination with 10-fold cross-validation.

RESULTS

The genetic score was significantly higher for cases than controls (P = 5.91 × 10(-20)), and was significantly associated with risk of PCa in a dose-dependent manner (P for trend: 4.78 × 10(-18)). The AUC of the genetic score was 0.604 for risk prediction of PCa in Chinese men. When ORs derived from this Chinese study population were used to calculate genetic score, the AUCs were 0.631 for all 33 SNPs and 0.617 when using only the 11 significant SNPs.

CONCLUSION

Our results indicate that genetic variants related to PCa risk may be useful for risk prediction in Chinese men. Prospective studies are warranted to further evaluate these findings.

Non-steroidal anti-inflammatory drug use and the risk of benign prostatic hyperplasia-related outcomes and nocturia in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial

Study Type - Therapy (cohort) Level of Evidence 4. What's known on the subject? and What does the study add? Accumulating evidence suggests that inflammation may contribute to the development of BPH and LUTS. Therefore, it is plausible that anti-inflammatory agents, such as aspirin and other NSAIDs, may reduce the risk of BPH/LUTS, as was observed in a recent analysis of daily aspirin use and BPH/LUTS risk in the Olmsted County Study of Urinary Symptoms and Health Status in Men. The present study, conducted in the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial, found no association for recent aspirin or ibuprofen use with the risk of BPH/LUTS.

OBJECTIVE

To investigate the relationship between non-steroidal anti-inflammatory drug (NSAID) use and the incidence of benign prostatic hyperplasia (BPH)-related outcomes and nocturia, a lower urinary tract symptom (LUTS) of BPH, in light of accumulating evidence suggesting a role for inflammation in BPH/LUTS development.

PATIENTS AND METHODS

At baseline, participants in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial completed questions on recent, regular aspirin and ibuprofen use, BPH surgery, diagnosis of an enlarged prostate/BPH, and nocturia. Participants in the intervention arm also underwent a digital rectal examination (DRE), from which prostate dimensions were estimated, as well as a prostate-specific antigen (PSA) test. Only participants in the intervention arm without BPH/LUTS at baseline were included in the analysis (n= 4771). • During follow-up, participants underwent annual DREs and PSA tests, provided annual information on finasteride use, and completed a supplemental questionnaire in 2006-2008 that included additional questions on diagnosis of an enlarged prostate/BPH and nocturia. • Information collected was used to investigate regular aspirin or ibuprofen use in relation to the incidence of six BPH/LUTS definitions: diagnosis of an enlarged prostate/BPH, nocturia (waking two or more times per night to urinate), finasteride use, any self-reported BPH/LUTS, prostate enlargement (estimated prostate volume ≥30 mL on any follow-up DRE) and elevation in PSA level (>1.4 ng/mL on any follow-up PSA test).

RESULTS

Generally, null results were observed for any recent, regular aspirin or ibuprofen use (risk ratio = 0.92-1.21, P= 0.043-0.91) and frequency of use (risk ratios for one category increase in NSAID use = 0.98-1.11, P-trends = 0.10-0.99) with incident BPH/LUTS.

CONCLUSION

The findings obtained in the present study do not support a protective role for recent NSAID use in BPH/LUTS development.

Physical activity, diabetes, and thyroid cancer risk: a pooled analysis of five prospective studies

PURPOSE: Although many studies have linked obesity with increased risk of thyroid cancer, few have investigated the role of obesity-related lifestyle characteristics and medical conditions in the etiology of this disease. We examined the associations of self-reported physical activity and diabetes history with thyroid cancer risk in a large pooled analysis of prospective cohort studies. METHODS: Data from five prospective studies in the U.S. (n = 362,342 men, 312,149 women) were coded using standardized exposure, covariate, and outcome definitions. Hazard ratios (HR) and 95% confidence intervals (CI) for thyroid cancer were estimated using age as the time metric and adjusting for sex, education, race, marital status, cigarette smoking, body mass index, alcohol intake, and cohort. Effect modification by other risk factors (e.g., age, sex, and body mass index) and differences by cancer subtype (e.g., papillary, follicular) were also examined. RESULTS: Over follow-up (median = 10.5 years), 308 men and 510 women were diagnosed with a first primary thyroid cancer. Overall, subjects reporting the greatest amount of physical activity had an increased risk of the disease (HR = 1.18, 95% CI:1.00-1.39); however, this association was restricted to participants who were overweight/obese (≥25 kg/m(2); HR = 1.34, 95% CI:1.09-1.64) as opposed to normal-weight (<25 kg/m(2); HR = 0.92, 95% CI:0.69-1.22; P-interaction = 0.03). We found no overall association between self-reported history of diabetes and thyroid cancer risk (HR = 1.08, 95% CI:0.83-1.40). CONCLUSION: Neither physical inactivity nor diabetes history was associated with increased risk of thyroid cancer. While it may have been a chance finding, the possible increased risk associated with greater physical activity warrants further investigation.

Prostate cancer screening in the randomized Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial: mortality results after 13 years of follow-up

BACKGROUND

The prostate component of the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial was undertaken to determine whether there is a reduction in prostate cancer mortality from screening using serum prostate-specific antigen (PSA) testing and digital rectal examination (DRE). Mortality after 7-10 years of follow-up has been reported previously. We report extended follow-up to 13 years after the trial.

METHODS

A total of 76 685 men, aged 55-74 years, were enrolled at 10 screening centers between November 1993 and July 2001 and randomly assigned to the intervention (organized screening of annual PSA testing for 6 years and annual DRE for 4 years; 38 340 men) and control (usual care, which sometimes included opportunistic screening; 38 345 men) arms. Screening was completed in October 2006. All incident prostate cancers and deaths from prostate cancer through 13 years of follow-up or through December 31, 2009, were ascertained. Relative risks (RRs) were estimated as the ratio of observed rates in the intervention and control arms, and 95% confidence intervals (CIs) were calculated assuming a Poisson distribution for the number of events. Poisson regression modeling was used to examine the interactions with respect to prostate cancer mortality between trial arm and age, comorbidity status, and pretrial PSA testing. All statistical tests were two-sided.

RESULTS

Approximately 92% of the study participants were followed to 10 years and 57% to 13 years. At 13 years, 4250 participants had been diagnosed with prostate cancer in the intervention arm compared with 3815 in the control arm. Cumulative incidence rates for prostate cancer in the intervention and control arms were 108.4 and 97.1 per 10 000 person-years, respectively, resulting in a relative increase of 12% in the intervention arm (RR = 1.12, 95% CI = 1.07 to 1.17). After 13 years of follow-up, the cumulative mortality rates from prostate cancer in the intervention and control arms were 3.7 and 3.4 deaths per 10 000 person-years, respectively, resulting in a non-statistically significant difference between the two arms (RR = 1.09, 95% CI = 0.87 to 1.36). No statistically significant interactions with respect to prostate cancer mortality were observed between trial arm and age (P(interaction) = .81), pretrial PSA testing (P(interaction) = .52), and comorbidity (P(interaction) = .68).

CONCLUSIONS

After 13 years of follow-up, there was no evidence of a mortality benefit for organized annual screening in the PLCO trial compared with opportunistic screening, which forms part of usual care, and there was no apparent interaction with age, baseline comorbidity, or pretrial PSA testing.

The association between inflammation-related genes and serum androgen levels in men: the prostate, lung, colorectal, and ovarian study

BACKGROUND

Androgens and inflammation have been implicated in the etiology of several cancers, including prostate cancer. Serum androgens have been shown to correlate with markers of inflammation and expression of inflammation-related genes.

METHODS

In this report, we evaluated associations between 9,932 single nucleotide polymorphisms (SNPs) marking common genetic variants in 774 inflammation-related genes and four serum androgen levels (total testosterone [T], bioavailable T [BioT]; 5α-androstane-3α, 17β-diol glucuronide [3αdiol G], and 4-androstene-3,17-dione [androstenedione]), in 560 healthy men (median age 64 years) drawn from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. Baseline serum androgens were measured by radioimmunoassay. Genotypes were determined as part of the Cancer Genetic Markers of Susceptibility Study genome-wide scan. SNP-hormone associations were evaluated using linear regression of hormones adjusted for age. Gene-based P values were generated using an adaptive rank truncated product (ARTP) method.

RESULTS

Suggestive associations were observed for two inflammation-related genes and circulating androgen levels (false discovery rate [FDR] q-value <0.1) in both SNP and gene-based tests. Specifically, T was associated with common variants in MMP2 and CD14, with the most significant SNPs being rs893226G > T in MMP2 and rs3822356T > C in CD14 (FDR q-value = 0.09 for both SNPs). Other genes implicated in either SNP or gene-based tests were IK with T and BioT, PRG2 with T, and TNFSF9 with androstenedione.

CONCLUSION

These results suggest possible cross-talk between androgen levels and inflammation pathways, but larger studies are needed to confirm these findings and to further clarify the interrelationship between inflammation and androgens and their effects on cancer risk.

Replication and cumulative effects of GWAS-identified genetic variations for prostate cancer in Asians: a case-control study in the ChinaPCa consortium

A recent genome-wide association study has identified five new genetic variants for prostate cancer susceptibility in a Japanese population, but it is unknown whether these newly identified variants are associated with prostate cancer risk in other populations, including Chinese men. We genotyped these five variants in a case-control study of 1524 patients diagnosed with prostate cancer and 2169 control subjects from the Chinese Consortium for Prostate Cancer Genetics (ChinaPCa). We found that three of the five genetic variants were associated with prostate cancer risk (P = 4.33 × 10(-8) for rs12653946 at 5p15, 4.43 × 10(-5) for rs339331 at 6q22 and 8.42 × 10(-4) for rs9600079 at 13q22, respectively). A cumulative effect was observed in a dose-dependent manner with increasing numbers of risk variant alleles (P(trend) = 2.58 × 10(-13)), and men with 5-6 risk alleles had a 2-fold higher risk of prostate cancer than men with 0-2 risk alleles (odds ratio = 2.26, 95% confidence interval = 1.78-2.87). Furthermore, rs339331 T allele was significantly associated with RFX6 and GPRC6A higher messenger RNA expression, compared with the C allele. However, none of the variants was associated with clinical stage, Gleason score or family history. These results provide further evidence that the risk loci identified in Japanese men also contribute to prostate cancer susceptibility in Chinese men.

Replication of five prostate cancer loci identified in an Asian population--results from the NCI Breast and Prostate Cancer Cohort Consortium (BPC3)

BACKGROUND

A recent genome-wide association study (GWAS) of prostate cancer in a Japanese population identified five novel regions not previously discovered in other ethnicities. In this study, we attempt to replicate these five loci in a series of nested prostate cancer case-control studies of European ancestry.

METHODS

We genotyped five single-nucleotide polymorphism (SNP): rs13385191 (chromosome 2p24), rs12653946 (5p15), rs1983891 (6p21), rs339331 (6p22), and rs9600079 (13q22), in 7,956 prostate cancer cases and 8,148 controls from a series of nested case-control studies within the National cancer Institute Breast and Prostate Cancer Cohort Consortium (BPC3). We tested each SNP for association with prostate cancer risk and assessed whether associations differed with respect to disease severity and age of onset.

RESULTS

Four SNPs (rs13385191, rs12653946, rs1983891, and rs339331) were significantly associated with prostate cancer risk (P values ranging from 0.01 to 1.1 × 10(-5)). Allele frequencies and ORs were overall lower in our population of European descent than in the discovery Asian population. SNP rs13385191 (C2orf43) was only associated with low-stage disease (P = 0.009, case-only test). No other SNP showed association with disease severity or age of onset. We did not replicate the 13q22 SNP, rs9600079 (P = 0.62).

CONCLUSIONS

Four SNPs associated with prostate cancer risk in an Asian population are also associated with prostate cancer risk in men of European descent.

IMPACT

This study illustrates the importance of evaluation of prostate cancer risk markers across ethnic groups.

A genome-wide association study identifies a novel susceptibility locus for renal cell carcinoma on 12p11.23

Renal cell carcinoma (RCC) is the most lethal urologic cancer. Only two common susceptibility loci for RCC have been confirmed to date. To identify additional RCC common susceptibility loci, we conducted an independent genome-wide association study (GWAS). We analyzed 533 191 single nucleotide polymorphisms (SNPs) for association with RCC in 894 cases and 1516 controls of European descent recruited from MD Anderson Cancer Center in the primary scan, and validated the top 500 SNPs in silico in 3772 cases and 8505 controls of European descent involved in the only published GWAS of RCC. We identified two common variants in linkage disequilibrium, rs718314 and rs1049380 (r(2) = 0.64, D ' = 0.84), in the inositol 1,4,5-triphosphate receptor, type 2 (ITPR2) gene on 12p11.23 as novel susceptibility loci for RCC (P = 8.89 × 10(-10) and P = 6.07 × 10(-9), respectively, in meta-analysis) with an allelic odds ratio of 1.19 [95% confidence interval (CI): 1.13-1.26] for rs718314 and 1.18 (95% CI: 1.12-1.25) for rs1049380. It has been recently identified that rs718314 in ITPR2 is associated with waist-hip ratio (WHR) phenotype. To our knowledge, this is the first genetic locus associated with both cancer risk and WHR.

Joint associations between genetic variants and reproductive factors in glioma risk among women

In a pooled analysis of 4 US epidemiologic studies (1993-2001), the authors evaluated the role of 5 female reproductive factors in 357 women with glioma and 822 controls. The authors further evaluated the independent association between 5 implicated gene variants and glioma risk among the study population, as well as the joint associations of female reproductive factors (ages at menarche and menopause, menopausal status, use of oral contraceptives, and menopausal hormone therapy) and these gene variants on glioma risk. Risk estimates were calculated as odds ratios and 95% confidence intervals that were adjusted for age, race, and study. Three of the gene variants (rs4295627, a variant of CCDC26; rs4977756, a variant of CDKN2A and CDKN2B; and rs6010620, a variant of RTEL1) were statistically significantly associated with glioma risk in the present population. Compared with women who had an early age at menarche (<12 years of age), those who reported menarche at 12-13 years of age or at 14 years of age or older had a 1.7-fold higher risk and a 1.9-fold higher risk of glioma, respectively (P for trend = 0.009). Postmenopausal women and women who reported ever having used oral contraceptives had a decreased risk of glioma. The authors did not observe joint associations between these reproductive characteristics and the implicated glioma gene variants. These results require replication, but if confirmed, they would suggest that the gene variants that have previously been implicated in the development of glioma are unlikely to act through the same hormonal mechanisms in women.

Persistence of type-specific human papillomavirus infection and increased long-term risk of cervical cancer

BACKGROUND

Human papillomavirus (HPV) persistence is the pivotal event in cervical carcinogenesis. We followed a large-scale community-based cohort for 16 years to investigate the role of genotype-specific HPV persistence in predicting cervical cancer including invasive and in situ carcinoma.

METHODS

At the baseline examination in 1991-1992, 11,923 participants (aged 30-65 years) consented to HPV testing and cytology; 6923 participants were reexamined in 1993-1995. For HPV testing, we used a polymerase chain reaction-based assay that detected 39 HPV types. Women who developed cervical cancer were identified from cancer and death registries. Cumulative risks for developing cervical cancer among infected and persistently infected women were calculated by the Kaplan-Meier method.

RESULTS

Of 10,123 women who were initially cytologically normal, 68 developed cervical cancer. The 16-year cumulative risks of subsequent cervical cancer for women with HPV16, HPV58 (without HPV16), or other carcinogenic HPV types (without HPV16 or HPV58) were 13.5%, 10.3%, and 4.0%, respectively, compared with 0.26% for HPV-negative women. Women with type-specific persistence of any carcinogenic HPV had greatly increased risk compared with women who were HPV-negative at both visits (hazard ratio = 75.4, 95% confidence interval = 31.8 to 178.9). The cumulative cervical cancer risks following persistent carcinogenic HPV infections increased with age: The risks were 5.5%, 14.4%, and 18.1% for women aged 30-44 years, 45-54 years, and 55 years and older, respectively. However, newly acquired infections were associated with a low risk of cervical cancer regardless of age.

CONCLUSIONS

HPV negativity was associated with a very low long-term risk of cervical cancer. Persistent detection of HPV among cytologically normal women greatly increased risk. Thus, it is useful to perform repeated HPV testing following an initial positive test.

Abstract B42: A comprehensive resequence-analysis of 250kb region of 8q24 in Africans

The centromeric region flanking the MYC oncogene on 8q24 harbors at least 5 independent loci associated with prostate cancer as well as additional loci associated with distinct cancers of the breast, colon, bladder, and chronic lymphocytic leukemia, all discovered in genome-wide association studies (GWAS). One of the regions has been defined as a 250kb span of 8q24 by linkage disequilibrium (LD) pattern and recombination hotspots (chr8:128050768-128300801, hg19) that contains prostate cancer susceptibility loci rs13254738 and rs16901979, as well as a locus rs2456449 associated with chronic lymphocytic leukemia. Because GWAS identify genetic markers, fine-mapping, based on sequence analysis is necessary to define the optimal variants for biological follow-up. Sequence analysis in distinct populations can provide important insights into the differences in patterns of LD and thus narrow down high interest variants. We have resequenced this region in samples of African ancestry using next-generation technology to comprehensively catalogue variations. Our study sample set included a total of 128 individuals from a population-based study in Ghana. In comparison to the 1000 genome data, we have identified additional variants, which could be important in establishing priorities for future functional work, designed to explain the biological basis of the association signal for both prostate cancer and chronic lymphocytic leukemia.

Citation Information: Cancer Epidemiol Biomarkers Prev 2011;20(10 Suppl):B42.

Genome-wide association study of circulating retinol levels

Retinol is one of the most biologically active forms of vitamin A and is hypothesized to influence a wide range of human diseases including asthma, cardiovascular disease, infectious diseases and cancer. We conducted a genome-wide association study of 5006 Caucasian individuals drawn from two cohorts of men: the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study and the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial. We identified two independent single-nucleotide polymorphisms associated with circulating retinol levels, which are located near the transthyretin (TTR) and retinol binding protein 4 (RBP4) genes which encode major carrier proteins of retinol: rs1667255 (P =2.30× 10(-17)) and rs10882272 (P =6.04× 10(-12)). We replicated the association with rs10882272 in RBP4 in independent samples from the Nurses' Health Study and the Invecchiare in Chianti Study (InCHIANTI) that included 3792 women and 504 men (P =9.49× 10(-5)), but found no association for retinol with rs1667255 in TTR among women, thus suggesting evidence for gender dimorphism (P-interaction=1.31× 10(-5)). Discovery of common genetic variants associated with serum retinol levels may provide further insight into the contribution of retinol and other vitamin A compounds to the development of cancer and other complex diseases.

Systematic confirmation study of reported prostate cancer risk-associated single nucleotide polymorphisms in Chinese men

More than 30 prostate cancer (PCa) risk-associated loci have been identified in populations of European descent by genome-wide association studies. We hypothesized that a subset of these loci might be associated with PCa risk in Chinese men. To test this hypothesis, 33 single nucleotide polymorphisms (SNP), one each from the 33 independent PCa risk-associated loci reported in populations of European descent, were investigated for their associations with PCa risk in a case-control study of Chinese men (1108 cases and 1525 controls). We found that 11 of the 33 SNP were significantly associated with PCa risk in Chinese men (P < 0.05). The reported risk alleles were associated with increased risk for PCa, with allelic odds ratios ranging from 1.12 to 1.44. The most significant locus was located on 8q24 region 2 (rs16901979, P = 5.14 × 10(-9)) with a genome-wide significance (P < (-8) ), and three loci reached the Bonferroni correction significance level (P < 1.52 × 10(-3)), including 8q24 region 1 (rs1447295, P = 7.04 × 10(-6)), 8q24 region 5 (rs10086908, P = 9.24 × 10(-4)) and 8p21 (rs1512268, P = 9.39 × 10(-4)). Our results suggest that a subset of the PCa risk-associated SNP discovered by genome-wide association studies among men of European descent is also associated with PCa risk in Chinese men. This finding provides evidence of ethnic differences and similarity in genetic susceptibility to PCa. Genome-wide association studies in Chinese men are needed to identify Chinese-specific PCa risk-associated SNP.

Prostate cancer incidence rates in Africa

African American men have among the highest prostate cancer incidence rates in the world yet rates among their African counterparts are unclear. In this paper, we compared reported rates among black men of Sub-Saharan African descent using data from the International Agency for Research on Cancer (IARC) and the National Cancer Institute Surveillance, Epidemiology, and End Results Program for 1973-2007. Although population-based data in Africa are quite limited, the available data from IARC showed that rates among blacks were highest in the East (10.7-38.1 per 100,000 man-years, age-adjusted world standard) and lowest in the West (4.7-19.8). These rates were considerably lower than those of 80.0-195.3 observed among African Americans. Rates in Africa increased over time (1987-2002) and have been comparable to those for distant stage in African Americans. These patterns are likely due to differences between African and African American men in medical care access, screening, registry quality, genetic diversity, and Westernization. Incidence rates in Africa will likely continue to rise with improving economies and increasing Westernization, warranting the need for more high-quality population-based registration to monitor cancer incidence in Africa.

Medical history and the risk of biliary tract cancers in Shanghai, China: implications for a role of inflammation

Several lines of evidence suggest that inflammation may play a role in the etiology of biliary tract cancers. To examine further the role of inflammation, we evaluated the associations between self-reported inflammatory-related medical conditions and the risk of biliary tract cancers in a population-based case-control study in Shanghai, China. Our analysis included 368 gallbladder cancer cases, 191 bile duct cancer cases, 68 ampulla of Vater cancer cases, and 959 healthy subjects. We used logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for biliary tract cancers in relation to six inflammation-related conditions. Gallbladder cancer was significantly associated with cholecystitis occurring at least 5 years prior to interview (OR = 1.7, 95% CI 1.1-2.9). Even though biliary stones did not significantly modify the associations between cholecystitis and gallbladder cancer, 90% of the gallbladder cancer cases with cholecystitis also had biliary stones, indicating that stones likely play an important role in the link between cholecystitis and gallbladder cancer. Among subjects who smoked and drank alcohol, a history of gastric (OR = 4.3, 95% CI 1.2-15.0) or duodenal ulcers (OR = 3.7, 1.2-12.0) was associated with an excess risk of gallbladder cancer. Although the mechanisms are unclear, our results further support the role for inflammation in the etiology of biliary tract cancers.

High prevalence of polyclonal hypergamma-globulinemia in adult males in Ghana, Africa

Chronic antigenic stimulation is associated with hypergamma-globulinemia. Higher rates of hypergamma-globulinemia in tropical populations are maintained even with migration to temperate regions. We conducted a population-based screening study to assess the prevalence and risk factors for hypergamma-globulinemia in Ghana, Africa. 917 Ghanaian males (50-74 years) underwent in-person interviews and health examinations. Serum from all persons was analyzed by electrophoresis performed on agarose gel; serum with a discrete/localized band was subjected to immunofixation. 54 persons with monoclonal proteins were excluded and 17 samples were insufficient for analysis. Using logistic regression and Chi-square statistics we analyzed patterns of hypergamma-globulinemia. Among 846 study subjects, the median γ-globulin level was 1.86 g/dL. On the basis of a U.S. reference, 616 (73%) had hypergamma-globulinemia (>1.6 g/dL) and 178 (21%) had γ-globulin levels >2.17 gm/dl. On multivariate analyses, lower education status (P = 0.0013) and never smoking (P = 0.038) were associated with increased γ-globulin levels. Self-reported history of syphilis was associated with hypergamma-globulinemia. We conclude that three quarters of this population-based adult Ghanaian male sample had hypergamma-globulinemia with γ-globulin levels >1.6 g/dL. Future studies are needed to uncover genetic and environmental underpinnings of our finding, and to define the relationship between hypergamma-globulinemia, monoclonal gammopathy of undetermined significance (MGUS), and multiple myeloma.

Evaluation of multiplexed cytokine and inflammation marker measurements: a methodologic study

BACKGROUND

Chronic inflammation is etiologically related to several cancers. We evaluated the performance [ability to detect concentrations above the assay's lower limit of detection, coefficients of variation (CV), and intraclass correlation coefficients (ICC)] of 116 inflammation, immune, and metabolic markers across two Luminex bead-based commercial kits and three specimen types.

METHODS

From 100 cancer-free participants in the Prostate, Lung, Colorectal, and Ovarian Cancer Trial, serum, heparin plasma, and EDTA plasma samples were utilized. We measured levels of 67 and 97 markers using Bio-Rad and Millipore kits, respectively. Reproducibility was assessed using 40 blinded duplicates (20 within-batches and 20 across-batches) for each specimen type.

RESULTS

A majority of markers were detectable in more than 25% of individuals on all specimen types/kits. Of the 67 Bio-Rad markers, 51, 52, and 47 markers in serum, heparin plasma, and EDTA plasma, respectively, had across-batch CVs of less than 20%. Likewise, of 97 Millipore markers, 75, 69, and 78 markers in serum, heparin plasma, and EDTA plasma, respectively, had across-batch CVs of less than 20%. When results were combined across specimen types, 45 Bio-Rad and 71 Millipore markers had acceptable performance (>25% detectability on all three specimen types and across-batch CVs <20% on at least two of three specimen types). Median concentrations and ICCs differed to a small extent across specimen types and to a large extent between Bio-Rad and Millipore.

CONCLUSIONS

Inflammation and immune markers can be measured reliably in serum and plasma samples using multiplexed Luminex-based methods.

IMPACT

Multiplexed assays can be utilized for epidemiologic investigations into the role of inflammation in cancer etiology.

A reproducible and high-throughput HPLC/MS method to separate sarcosine from α- and β-alanine and to quantify sarcosine in human serum and urine

While sarcosine was recently identified as a potential urine biomarker for prostate cancer, further studies have cast doubt on its utility to diagnose this condition. The inconsistent results may be due to the fact that alanine and sarcosine coelute on an HPLC reversed-phase column and the mass spectrometer cannot differentiate between the two isomers, since the same parent/product ions are generally used to measure them. In this study, we developed a high-throughput liquid chromatography-mass spectrometry (LC-MS) method that resolves sarcosine from alanine isomers, allowing its accurate quantification in human serum and urine. Assay reproducibility was determined using the coefficient of variation (CV) and intraclass correlation coefficient (ICC) in serum aliquots from 10 subjects and urine aliquots from 20 subjects across multiple analytic runs. Paired serum/urine samples from 42 subjects were used to evaluate sarcosine serum/urine correlation. Both urine and serum assays gave high sensitivity (limit of quantitation of 5 ng/mL) and reproducibility (serum assay, intra- and interassay CVs < 3% and ICCs > 99%; urine assay, intra-assay CV = 7.7% and ICC = 98.2% and interassay CV = 12.3% and ICC = 94.2%). In conclusion, this high-throughput LC-MS method is able to resolve sarcosine from α- and β-alanine and is useful for quantifying sarcosine in serum and urine samples.

Serum estrogen levels and prostate cancer risk in the prostate cancer prevention trial: a nested case-control study

Objective

Finasteride reduces prostate cancer risk by blocking the conversion of testosterone to dihydrotestosterone. However, whether finasteride affects estrogens levels or change in estrogens affects prostate cancer risk is unknown.

Methods

These questions were investigated in a case–control study nested within the prostate cancer prevention trial (PCPT) with 1,798 biopsy-proven prostate cancer cases and 1,798 matched controls.

Results

Among men on placebo, no relationship of serum estrogens with risk of prostate cancer was found. Among those on finasteride, those in the highest quartile of baseline estrogen levels had a moderately increased risk of Gleason score < 7 prostate cancer (for estrone, odds ratio [OR] = 1.51, 95% confidence interval [CI] = 1.06–2.15; for estradiol, OR = 1.50, 95% CI = 1.03–2.18). Finasteride treatment increased serum estrogen concentrations; however, these changes were not associated with prostate cancer risk.

Conclusion

Our findings confirm those from previous studies that there are no associations of serum estrogen with prostate cancer risk in untreated men. In addition, finasteride results in a modest increase in serum estrogen levels, which are not related to prostate cancer risk. Whether finasteride is less effective in men with high serum estrogens, or finasteride interacts with estrogen to increase cancer risk, is uncertain and warrants further investigation.

Dietary carbohydrate, glycemic index, glycemic load, and risk of prostate cancer in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO) cohort

OBJECTIVE

To evaluate the associations between dietary carbohydrate, glycemic index (GI), glycemic load (GL), and incident prostate cancer in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO) cohort.

METHODS

Between September 1993 and September 2000, 38,343 men were randomized to the screening arm of the trial at one of 10 PLCO centers. A food frequency questionnaire administered at baseline assessed usual dietary intake over the preceding 12 months. Prostate cancer was ascertained by medical follow-up of suspicious screening results and annual mailed questionnaires and confirmed with medical records. Cox proportional hazards regression was used to model the associations of carbohydrate, GI, and GL with prostate cancer risk.

RESULTS

During follow-up (median = 9.2 years), 2,436 incident prostate cancers were identified among 30,482 eligible participants. Overall, there were no associations of baseline carbohydrate, GI, or GL with incident prostate cancer in minimally or fully adjusted models. There were no associations when the 228 advanced and 2,208 non-advanced cancers were analyzed separately.

CONCLUSIONS

Dietary carbohydrate, GI, and GL were not associated with incident prostate cancer in PLCO. The narrow range of GI in this cohort may have limited our ability to detect associations, an issue that future studies should address.

Chronic typhoid infection and the risk of biliary tract cancer and stones in Shanghai, China

Previous studies have shown a positive association between chronic typhoid carriage and biliary cancers. We compared serum Salmonella enterica serovar Typhi antibody titers between biliary tract cancer cases, biliary stone cases without evidence of cancer, and healthy subjects in a large population-based case-control study in Shanghai, China.

Participants included 627 newly diagnosed primary biliary tract cancer patients; 1,037 biliary stone cases (774 gallbladder and 263 bile-duct) and 959 healthy subjects without a history of cancer, randomly selected from the Shanghai Resident Registry.

Overall only 6/2,293 (0.26%) were Typhi positive. The prevalence of Typhi was 1/457 (0.22%), 4/977 (0.41%), and 1/859 (0.12%) among cancer cases, biliary-stone cases, and population controls, respectively.

We did not find an association between Typhi and biliary cancer in Shanghai, due to the very low prevalence of chronic carriers in this population.

The low seroprevalence of S. Typhi in Shanghai is unlikely to explain the high incidence of biliary cancers in this population.

Urinary estrogen metabolites and prostate cancer risk: a pilot study

BACKGROUND

The high incidence of and few identified risk factors for prostate cancer underscore the need to further evaluate markers of prostate carcinogenesis. The aim of this pilot study was to evaluate urinary estrogen metabolites as a biomarker of prostate cancer risk.

METHODS

Using a liquid chromatography-tandem mass spectrometry method, urinary concentrations of 15 estrogen metabolites were determined in 77 prostate cancer cases, 77 healthy controls, and 37 subjects who had no evidence of prostate cancer after a prostate biopsy.

RESULTS

We observed an inverse association between the urinary 16-ketoestradiol (16-KE2) and 17-epiestriol (17-epiE3)--metabolites with high estrogenic activity--and prostate cancer risk. Men in the lowest quartile of 16-KE2, had a 4.6-fold risk of prostate cancer (OR=4.62, 95% CI=1.34-15.99), compared with those in the highest quartile.

CONCLUSIONS

We observed modest differences in estrogen metabolite concentrations between prostate cancer patients and subjects without cancer. Larger studies with both androgen and estrogen measurements are needed to confirm these results to clarify further whether estrogen metabolites are independent biomarkers for prostate cancer risk and whether androgen/estrogen imbalance influences prostate cancer risk.

Finasteride metabolism and pharmacogenetics: new approaches to personalized prevention of prostate cancer

Incidences of prostate cancer in most countries are increasing owing to better detection methods; however, prevention with the use of finasteride, a very effective steroid 5α-reductase type II inhibitor, has been met with mixed success. A wide interindividual variation in response exists and is thought to be due to heritable factors. This article summarizes the literature that attempts to elucidate the molecular mechanisms of finasteride in terms of its metabolism, excretion and interaction with endogenous steroid molecules. We describe previously reported genetic variations of steroid-metabolizing genes and their potential association with finasteride efficacy. Based on the literature, we outline directions of research that may contribute to understanding the interindividual variation in finasteride prevention and to the future development of personalized medicine.

Obesity and thyroid cancer risk among U.S. men and women: a pooled analysis of five prospective studies

BACKGROUND

Thyroid cancer incidence has risen dramatically in the United States since the early 1980s. Although the prevalence of obesity has doubled during this time period, the relationship between obesity and thyroid cancer is uncertain.

METHODS

We examined the association between body mass index (BMI) and thyroid cancer risk in a pooled analysis of five prospective U.S. studies, including 413,979 women and 434,953 men. Proportional hazards models with attained age as the time metric were adjusted for education, race, marital status, smoking, alcohol intake, and (where appropriate) cohort and sex.

RESULTS

Over follow-up (mean=10.3 years), 768 women and 388 men were diagnosed with thyroid cancer. The risk of thyroid cancer was greater with increasing BMI [per 5 kg/m2: HR in women, 1.16 (95% CI, 1.08-1.24); HR in men, 1.21 (95% CI, 0.97-1.49)]. There was no significant heterogeneity between studies (both P>0.05). For women and men combined, the HRs for overweight (25.0-29.9 kg/m2) and obesity (≥30 kg/m2) compared with normal-weight (18.5-24.9 kg/m2) were 1.20 (95% CI, 1.04-1.38) and 1.53 (95% CI, 1.31-1.79), respectively. We found no significant effect modification by other factors, and the results did not differ significantly by histologic type. A significant positive association for BMI in young adulthood (ages 18-20) with thyroid cancer risk was also observed [per 5-kg/m2 increase: HR, 1.18 (95% CI, 1.03-1.35)].

CONCLUSION

BMI was positively associated with thyroid cancer risk in both men and women.

IMPACT

Our study provides strong evidence that obesity is an independent risk factor for thyroid cancer.

DNA damage phenotype and prostate cancer risk

The capacity of an individual to process DNA damage is considered a crucial factor in carcinogenesis. The comet assay is a phenotypic measure of the combined effects of sensitivity to a mutagen exposure and repair capacity. In this paper, we evaluate the association of the DNA repair kinetics, as measured by the comet assay, with prostate cancer risk. In a pilot study of 55 men with prostate cancer, 53 men without the disease, and 71 men free of cancer at biopsy, we investigated the association of DNA damage with prostate cancer risk at early (0-15 min) and later (15-45 min) stages following gamma-radiation exposure. Although residual damage within 45 min was the same for all groups (65% of DNA in comet tail disappeared), prostate cancer cases had a slower first phase (38% vs. 41%) and faster second phase (27% vs. 22%) of the repair response compared to controls. When subjects were categorized into quartiles, according to efficiency of repairing DNA damage, high repair-efficiency within the first 15 min after exposure was not associated with prostate cancer risk while higher at the 15-45 min period was associated with increased risk (OR for highest-to-lowest quartiles=3.24, 95% CI=0.98-10.66, p-trend=0.04). Despite limited sample size, our data suggest that DNA repair kinetics marginally differ between prostate cancer cases and controls. This small difference could be associated with differential responses to DNA damage among susceptible individuals.

Validation of genome-wide prostate cancer associations in men of African descent

BACKGROUND

Genome-wide association studies (GWAS) have identified numerous prostate cancer susceptibility alleles, but these loci have been identified primarily in men of European descent. There is limited information about the role of these loci in men of African descent.

METHODS

We identified 7,788 prostate cancer cases and controls with genotype data for 47 GWAS-identified loci.

RESULTS

We identified significant associations for SNP rs10486567 at JAZF1, rs10993994 at MSMB, rs12418451 and rs7931342 at 11q13, and rs5945572 and rs5945619 at NUDT10/11. These associations were in the same direction and of similar magnitude as those reported in men of European descent. Significance was attained at all reported prostate cancer susceptibility regions at chromosome 8q24, including associations reaching genome-wide significance in region 2.

CONCLUSION

We have validated in men of African descent the associations at some, but not all, prostate cancer susceptibility loci originally identified in European descent populations. This may be due to the heterogeneity in genetic etiology or in the pattern of genetic variation across populations.

IMPACT

The genetic etiology of prostate cancer in men of African descent differs from that of men of European descent.

Cholesterol metabolism gene polymorphisms and the risk of biliary tract cancers and stones: a population-based case-control study in Shanghai, China

Biliary tract cancers are rare but fatal malignancies, with increasing incidence in Shanghai, China. Gallstones, the primary risk factor for biliary tract cancer, typically result from oversaturation of cholesterol in bile. We examined the association of five variants in three lipid metabolism-related genes (CETP, ABCG8 and LRPAP1) and biliary tract cancers and stones in a population-based case-control study in Shanghai, China. We included 439 biliary tract cancer cases (253 gallbladder, 133 extrahepatic bile duct and 53 ampulla of Vater cancer cases), 429 biliary stone cases and 447 population controls. Carriers of the CG genotype of ABCG8 rs11887534 had higher risk of biliary stones [odds ratio (OR) = 2.3, 95% confidence interval (CI) 0.82-6.5), gallbladder cancer (OR = 4.3, 95% CI 1.7-10.4) and bile duct cancer (OR = 1.94, 95% CI 0.64-5.91), compared with carriers of the GG genotype. Analysis stratified by gender showed both male and female carriers of CG rs11887534 had higher risks of biliary stones and gallbladder cancer, although the association was statistically significant only for women and gallbladder cancer (OR = 6.3, 95% CI 1.86-22.3). Carriers of the ABCG8 haplotype C-C (rs4148217-rs11887534) had a 4.16-fold (95% CI 1.71-10.1) risk of gallbladder cancer compared with those carrying the C-G haplotype. Our findings suggest that ABCG8 rs11887534, identified as a gallstone risk single-nucleotide polymorphism by whole genome scan, is also associated with an increased risk of biliary tract cancer.

Androgen receptor CAG repeat length and association with prostate cancer risk: results from the prostate cancer prevention trial

PURPOSE

We investigated the association between the length of the polymorphic trinucleotide CAG microsatellite repeats in exon 1 of the AR gene and the risk of prostate cancer.

MATERIALS AND METHODS

This is a nested case-control study of 1,159 cases and 1,353 controls from the Prostate Cancer Prevention Trial, a randomized, placebo controlled trial testing whether the 5α-reductase inhibitor finasteride could decrease the 7-year prevalence of prostate cancer. During the course of the trial men underwent annual digital rectal examination and prostate specific antigen measurement. Prostate biopsy was recommended in all men with abnormal digital rectal examination or finasteride adjusted prostate specific antigen greater than 4.0 ng/ml. Cases were drawn from men with biopsy determined prostate cancer identified by for cause or end of study biopsy. Controls were selected from men who completed the end of study biopsy.

RESULTS

Mean CAG repeat length did not differ between cases and controls. The frequency distribution of cases and controls for the AR CAG repeat length was similar. There were no significant associations of CAG repeat length with prostate cancer risk when stratified by treatment arm (finasteride or placebo), or when combined. There was also no significant association between CAG repeat length and the risk of low or high grade prostate cancer.

CONCLUSIONS

There is no association of AR CAG repeat length with prostate cancer risk. Knowledge of AR CAG repeat length provides no clinically useful information to predict prostate cancer risk.

Identification of Serum Biomarkers for Biliary Tract Cancers by a Proteomic Approach Based on Time-of-Flight Mass Spectrometry

Biliary tract cancers (BTCs) are lethal malignancies currently lacking satisfactory methods for early detection and accurate diagnosis. Surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS) is a promising diagnostic tool for this disease. In this pilot study, sera samples from 50 BTCs and 30 cholelithiasis patients as well as 30 healthy subjects from a population-based case-control study were randomly grouped into training set (30 BTCs, 20 cholelithiasis and 20 controls), duplicate of training set, and blind set (20 BTCs, 10 cholelithiasis and 10 controls); all sets were analyzed on Immobilized Metal Affinity Capture ProteinChips via SELDI-TOF-MS. A decision tree classifier was built using the training set and applied to all test sets. The classification tree constructed with the 3,400, 4,502, 5,680, 7,598, and 11,242 mass-to-charge ratio (m/z) protein peaks had a sensitivity of 96.7% and a specificity of 85.0% when comparing BTCs with non-cancers. When applied to the duplicate set, sensitivity was 66.7% and specificity was 70.0%, while in the blind set, sensitivity was 95.0% and specificity was 75.0%. Positive predictive values of the training, duplicate, and blind sets were 82.9%, 62.5% and 79.2%, respectively. The agreement of the training and duplicate sets was 71.4% (Kappa = 0.43, u = 3.98, P < 0.01). The coefficient of variations based on 10 replicates of one sample for the five differential peaks were 15.8–68.8% for intensity and 0–0.05% for m/z. These pilot results suggest that serum protein profiling by SELDI-TOF-MS may be a promising approach for identifying BTCs but low assay reproducibility may limit its application in clinical practice.

Association between genetic variants in the 8q24 cancer risk regions and circulating levels of androgens and sex hormone-binding globulin

BACKGROUND

Genome-wide association studies have identified multiple independent regions on chromosome 8q24 that are associated with cancers of the prostate, breast, colon, and bladder.

METHODS

To investigate their biological basis, we examined the possible association between 164 single nucleotide polymorphisms (SNPs) in the 8q24 risk regions spanning 128,101,433-128,828,043 bp, and serum androgen (testosterone, androstenedione, 3alphadiol G, and bioavailable testosterone), and sex hormone-binding globulin levels in 563 healthy, non-Hispanic, Caucasian men (55-74 years old) from a prospective cohort study (the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial). Age-adjusted linear regression models were used to determine the association between the SNPs in an additive genetic model and log-transformed biomarker levels.

RESULTS

Three adjacent SNPs centromeric to prostate cancer risk-region 2 (rs12334903, rs1456310, and rs980171) were associated with testosterone (P < 1.1 x 10(-3)) and bioavailable testosterone (P < 6.3 x 10(-4)). Suggestive associations were seen for a cluster of nine SNPs in prostate cancer risk region 1 and androstenedione (P < 0.05).

CONCLUSIONS

These preliminary findings require confirmation in larger studies but raise the intriguing hypothesis that genetic variations in the 8q24 cancer risk regions might correlate with androgen levels.

IMPACT

These results might provide some clues for the strong link between 8q24 and prostate cancer risk.

Human papillomavirus types 16, 18, and 31 serostatus and prostate cancer risk in the Prostate Cancer Prevention Trial

Since human papillomavirus (HPV) infection was first identified as a risk factor for cervical cancer, several seroepidemiologic and tissue-based studies have investigated HPV in relation to prostate cancer, another common genitourinary malignancy, with mixed results. To further inform this potential association, we conducted a large, prospective investigation of HPV types 16, 18, and 31 in relation to risk of prostate cancer in the Prostate Cancer Prevention Trial. Cases were a sample of men diagnosed with prostate cancer after visit 2 or on their end-of-study biopsy (n = 616). Controls were men not diagnosed with prostate cancer during the trial or on their end-of-study biopsy (n = 616). Controls were frequency matched to cases by age, treatment arm, and family history of prostate cancer. Sera from visit 2 were tested for IgG antibodies against HPV types 16, 18, and 31. No associations were observed for weak or strong HPV-16 [odds ratio (OR), 0.94; 95% confidence interval (95% CI), 0.53-1.64 and OR, 1.07; 95% CI, 077-1.48, respectively], HPV-18 (OR, 0.75; 95% CI, 0.27-2.04 and OR, 0.87; 95% CI, 0.47-1.63, respectively), or HPV-31 seropositivity (OR, 0.76; 95% CI, 0.45-1.28 and OR, 1.15; 95% CI, 0.80-1.64, respectively) and risk of prostate cancer. Considering this finding in the context of the HPV and prostate cancer literature, HPV does not appear to be associated with risk of prostate cancer, at least by mechanisms proposed to date, and using epidemiologic designs and laboratory techniques currently available.

Abstract 4732: Association between genetic variants in the 8q24 cancer risk regions and circulating levels of androgens and sex-hormone binding globulin

Multiple genome-wide association studies have identified several independent non-coding regions in chromosome 8q24 associated with risk for cancers of the prostate, breast, colon, and bladder. To explore their biological basis, we investigated the possible association between 164 single nucleotide polymorphism (SNPs) in the 8q24 risk regions, spanning 128,101,433-128,828,043 bp, and serum androgen (testosterone, androstenedione, and 3αdiol G) and sex hormone-binding globulin levels in 563 healthy, non-Hispanic, Caucasian men (55-74 years old) from a prospective cohort study, the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial. Age-adjusted linear regression using SNPs in an additive genetic model showed that three adjacent SNPs centromeric to prostate cancer risk region 2 (rs12334903, rs1456310, and rs980171) were associated with measured total testosterone (P&lt;1.1×10−3) and calculated bioavailable testosterone (P&lt;6.3×10−4). Suggestive associations were seen for a cluster of 9 SNPs in prostate cancer risk region 1 and androstenedione (P&lt;0.05). These preliminary findings, although in need of confirmation in larger studies, suggest that genetic variations in the 8q24 cancer risk regions may correlate with androgen levels, which in turn may provide some clues for the strong link between 8q24 and prostate cancer risk.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4732.

Abstract 924: Possible joint effects between single nucleotide polymorphisms in inflammation genes and serum androgen levels on risk of prostate cancer

Both inflammation and androgens are likely to be involved in the etiology of prostate cancer. There is evidence for cross-talk between androgen and inflammation pathways, yet little is known about the joint contribution of inflammation and androgens to prostate cancer risk. Thus, we evaluated the joint effects of 9,932 tag single nucleotide polymorphisms (SNPs) in 774 inflammation-related genes and four serum androgen measures (total testosterone [T], bioavailable T, 3α-androstanediol glucuronide [3α diol G], and androstenedione) on risk of prostate cancer in 516 incident cancer cases and 560 controls from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. SNPs included in this study were genotyped as part of the National Cancer Institute Cancer Genetic Markers of Susceptibility genome-wide association study. Likelihood ratio tests (LRT) were used to compare logistic models of prostate cancer regressed on age, center, the androgen (in quartiles), the SNP (additive genetic coding) and the SNP x hormone interaction term to logistic models of prostate cancer regressed on age, center, and the androgen. False discovery rate (FDR) control was used to adjust for multiple testing. Statistically significant LRT P-values were noted for T and three intronic SNPs in linkage disequilibrium (r2&gt;0.7) within the HIPK2 gene on 7q34 (rs10256326, rs7788362, and rs12539357; FDR-adjusted P=0.04 for all SNPs). For each SNP, the minor allele was associated with a reduced prostate cancer risk in men with serum T levels in the lower three quartiles, but was associated with an increased risk among men in the highest quartile of serum T. LRT P-values of borderline statistical significance were also seen for joint effects of these three SNPs and bioavailable T on risk of prostate cancer (FDR-adjusted P=0.07 for all SNPs). There were no significant joint effects for any of the SNPs with 3αdiol G or androstenedione after adjustment for multiple tests. Our preliminary results suggest that T levels could interact with HIPK2 gene variants to influence prostate cancer risk. HIPK2 is an attractive candidate gene for further evaluation because it codes for a serine/threonine kinase involved in transcriptional regulation, particularly involved in p53-dependent and independent regulation of cell cycle control and apoptosis. Future studies are needed to confirm our preliminary findings and to further understand the possible interaction between T and genetic variants in HIPK2, which could contribute to prostate cancer risk.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 924.

Simultaneous recovery of DNA and RNA from formalin-fixed paraffin-embedded tissue and application in epidemiologic studies

Analysis of DNA, RNA, and protein extracted from tissue specimens in epidemiologic studies is useful for assessing etiologic heterogeneity, mechanisms of carcinogenesis, and biomarkers for prognosis and prediction of treatment responses. Fresh-frozen tissue samples may provide optimal quality nucleic acids, but pose multiple logistical considerations, including rapid access to tissues before histopathologic examination and specialized equipment for freezing, transport, and storage; in addition, morphology is often compromised. In contrast, formalin-fixed paraffin-embedded (FFPE) tissue samples, including enormous archives of existing specimens, represent a valuable source of retrospective biological material for epidemiologic research, although presenting different limitations compared with frozen samples. Recent efforts have made progress toward enhancing the utility of FFPE specimens for molecular analyses, including DNA studies, and increasingly for RNA and other macromolecules. Here, we report the method that we used to simultaneously recover DNA and RNA from FFPE tissue specimens with appreciable quantity and quality and discuss briefly the application of tumor markers in epidemiologic studies.

Reproductive factors and risks of biliary tract cancers and stones: a population-based study in Shanghai, China

BACKGROUND

Parity has been linked to gallbladder cancer and gallstones, but the effects of other reproductive factors are less clear.

METHODS

We examined 361 incident biliary tract cancer cases, 647 biliary stone cases, and 586 healthy women in a population-based study in Shanghai.

RESULTS

The effects of parity (odds ratios, OR(> or =3 vs 1 child)=2.0, 95% confidence interval (CI) 0.7-5.1), younger age at first birth (OR(per 1-year decrease)=1.2, 95% CI 0.99-1.6), and older age at menarche (OR(per 1-year increase)=1.4, 95% CI 1.1-1.8) on gallbladder cancer risk were more pronounced among women with stones, but the interactions were not significant.

CONCLUSION

Our results provide support for high parity, younger age at first birth, and late age at menarche in the development of gallbladder cancer, particularly among women with biliary stones.

Serum oxidized protein and prostate cancer risk within the Prostate Cancer Prevention Trial

To evaluate the role of oxidative stress in prostate cancer risk, we analyzed serum levels of protein carbonyl groups in 1,808 prostate cancer cases and 1,805 controls, nested in the Prostate Cancer Prevention Trial, a randomized, placebo-controlled trial that found finasteride decreased prostate cancer risk. There were no significant differences in protein carbonyl levels in baseline samples between those later diagnosed with prostate cancer and those without at the end of study biopsy. Adjusted odds ratios and 95% confidence intervals (95% CI) for the 4th quartile of protein carbonyl level for the combined, placebo, and finasteride arms were 1.03 (95% CI, 0.85-1.24), 0.88 (95% CI, 0.69-1.12), and 1.27 (95% CI, 0.94-1.71), respectively. There were no significant associations between carbonyl level and risk when analyzing high-grade and low-grade disease separately, nor did finasteride affect protein oxidation levels. The results of this large nested case-control study do not support the hypothesis that oxidative stress, at least as measured by protein carbonyl level, plays a role in prostate cancer.

Limitations of direct immunoassays for measuring circulating estradiol levels in postmenopausal women and men in epidemiologic studies

Serum estradiol (E(2)) serves as an important diagnostic marker in a variety of clinical conditions. In epidemiologic studies, E(2) is commonly used to define the etiologic role of estrogen in hormone-related cancers and chronic conditions. Having an accurate and reliable E(2) assay is of critical importance in these studies, especially when measuring the very low E(2) levels (<30 pg/mL) common in postmenopausal women and men, and for discerning the relatively small (usually <20%) case-control differences in E(2) levels. Because E(2) is metabolized to >100 metabolites in the body, some of which cross-react with E(2) antibodies, direct RIAs without purification steps lack specificity for E(2) and can substantially overestimate E(2) levels. Although direct E(2) RIAs using commercial kits are simpler, less time consuming, and less expensive and require less sample volume than conventional RIAs with preceding purification steps, their lack of sensitivity and specificity makes them invalid for measuring circulating E(2) levels in epidemiologic studies of postmenopausal women or men. Instead, we recommend the use of a well-validated RIA with purification steps to improve sensitivity and specificity and to help achieve the necessary accuracy and reliability needed for epidemiologic studies.

Measuring serum melatonin in epidemiologic studies

BACKGROUND

Epidemiologic data on serum melatonin, a marker of circadian rhythms, and cancer are sparse due largely to the lack of reliable assays with high sensitivity to detect relatively low melatonin levels in serum collected during daylight, as commonly available in most epidemiologic studies.

METHODS

To help expand epidemiologic research on melatonin, we assessed the reproducibility and refined a currently available melatonin RIA, and evaluated its application to epidemiologic investigations by characterizing melatonin levels in serum, urine, and/or plasma in 135 men from several ethnic groups.

RESULTS

Reproducibility was high for the standard 1.0-mL serum [mean coefficient of variation (CV), 6.9%; intraclass correlation coefficient (ICC), 97.4%; n = 2 serum pools in triplicate] and urine-based (mean CV, 3.5%; ICC, 99.9%) assays. Reproducibility for the 0.5-mL refined-serum assay was equally good (mean CV, 6.6%; ICC, 99.0%). There was a positive correlation between morning serum melatonin and 6-sulfatoxymelatonin in 24-hour urine (r = 0.46; P = 0.008; n = 49 subjects). Melatonin levels in serum-plasma pairs had a high correlation (r = 0.97; P < 1x10(-4); n = 20 pairs). Morning serum melatonin levels were five times higher than those from the afternoon (before 9 a.m. mean, 11.0 pg/mL, versus after 11 a.m. mean, 2.0 pg/mL). Chinese men had lower melatonin levels (mean, 3.4 pg/mL), whereas Caucasian, African-American, and Ghanaian men had similar levels (mean, 6.7-8.6 pg/mL).

CONCLUSIONS

These results suggest that melatonin can be detected reliably in serum samples collected in epidemiologic studies in various racial groups.

IMPACT

With improved assays, it may be possible to investigate the role of melatonin and the emerging circadian rhythm hypothesis in cancer etiology in epidemiologic studies.

Androgen receptor CAG repeat length and risk of biliary tract cancer and stones

Biliary tract cancers, encompassing cancers of the gallbladder, extrahepatic bile ducts, and ampulla of Vater, are rare but highly fatal. Gallstones represent the major risk factor for biliary tract cancer, and share with gallbladder cancer a female predominance and an association with reproductive factors and obesity. Although estrogens have been implicated in earlier studies of gallbladder cancer, there are no data on the role of androgens. Because intracellular androgen activity is mediated through the androgen receptor (AR), we examined associations between AR CAG repeat length [(CAG)(n)] and the risk of biliary tract cancers and stones in a population-based study of 331 incident cancer cases, 837 gallstone cases, and 750 controls from Shanghai, China, where the incidence rates for biliary tract cancer are rising sharply. Men with (CAG)(n) >24 had a significant 2-fold risk of gallbladder cancer [odds ratio (OR), 2.00; 95% confidence interval (CI), 1.07-3.73], relative to those with (CAG)(n) < or = 22. In contrast, women with (CAG)(n) >24 had reduced gallbladder cancer risk (OR, 0.69; 95% CI, 0.43-1.09) relative to those with (CAG)(n) < or = 22; P interaction sex = 0.01, which was most pronounced for women ages 68 to 74 (OR, 0.48; 95% CI, 0.25-0.93; P interaction age = 0.02). No associations were found for bile duct cancer or gallstones. Reasons for the heterogeneity of genetic effects by gender and age are unclear but may reflect an interplay between AR and the levels of androgen as well as estrogen in men and older women. Further studies are needed to confirm these findings and clarify the mechanisms involved.

Association of 17 prostate cancer susceptibility loci with prostate cancer risk in Chinese men

BACKGROUND

Several genome-wide association studies (GWAS) in populations of European descent have identified more than a dozen common genetic variants that are associated with prostate cancer risk.

METHODS

To determine whether these variants are also associated with prostate cancer risk in the Chinese population, we evaluated 17 prostate cancer susceptibility loci in a population-based case-control study from Shanghai, including 288 prostate cancer cases and 155 population controls.

RESULTS

After adjustment for age, two of the 17 loci were significantly associated with prostate cancer risk, while the other 15 loci were suggestively associated with prostate cancer risk in this population. The strongest associations were found for chromosome 8q24 Region 2 (rs1016343: OR = 2.07, 95% CI: 1.35-3.20, P = 9.4 x 10(-4)) and 8q24 Region 1 (rs10090154: OR = 2.07, 95% CI: 1.31-3.28, P = 0.002); additional single nucleotide polymorphisms (SNPs) assessed in these two 8q24 regions were also significant (OR(Region2) = 1.92-2.05, P = 9.4 x 10(-4) to 0.003, and OR(Region1) = 1.77-1.81, P = 0.01 for all SNPs).

CONCLUSIONS

Our study shows that multiple prostate cancer risk loci identified in European populations by GWAS are also associated with prostate cancer risk in Chinese men, a low-risk population with mostly clinically relevant cancers. Larger studies in Chinese and Asian populations are needed to confirm these findings and the role of these risk loci in prostate cancer etiology in Asian men.

Finasteride modifies the relation between serum C-peptide and prostate cancer risk: results from the Prostate Cancer Prevention Trial

Hyperinsulinemia and obesity-related metabolic disturbances are common and have been associated with increased cancer risk and poor prognosis. To investigate this issue in relation to prostate cancer, we conducted a nested case-control study within the Prostate Cancer Prevention Trial (PCPT), a randomized, placebo-controlled trial testing finasteride versus placebo for primary prevention of prostate cancer. Cases (n = 1,803) and controls (n = 1,797) were matched on age, PCPT treatment arm, and family history of prostate cancer; controls included all eligible non-whites. Baseline bloods were assayed for serum C-peptide (marker of insulin secretion) and leptin (an adipokine) using ELISA. All outcomes were biopsy determined. Logistic regression calculated odds ratios (OR) for total prostate cancer and polytomous logistic regression calculated ORs for low-grade (Gleason <7) and high-grade (Gleason >7) disease. Results were stratified by PCPT treatment arm for C-peptide. For men on placebo, higher versus lower serum C-peptide was associated with a nearly 2-fold increased risk of high-grade prostate cancer (Gleason >7; multivariate-adjusted OR, 1.88; 95% confidence interval, 1.19-2.97; P(trend) = 0.004). When C-peptide was modeled as a continuous variable, every unit increase in log(C-peptide) resulted in a 39% increased risk of high-grade disease (P = 0.01). In contrast, there was no significant relationship between C-peptide and high-grade prostate cancer among men receiving finasteride. Leptin was not independently associated with high-grade prostate cancer. In conclusion, these results support findings from other observational studies that high serum C-peptide and insulin resistance, but not leptin, are associated with increased risk of high-grade prostate cancer. Our novel finding is that the C-peptide-associated risk was attenuated by use of finasteride.

Polymorphisms of estrogen receptors and risk of biliary tract cancers and gallstones: a population-based study in Shanghai, China

Biliary tract cancer encompasses tumors of the gallbladder, bile duct and ampulla of Vater. Gallbladder cancer is more common in women, whereas bile duct cancer is more common in men, suggesting that sex hormones may play a role in the etiology of these cancers. The intracellular action of estrogens is regulated by the estrogen receptor (ESR); thus, we examined the role of common genetic variants in ESR genes on the risk of biliary tract cancers and stones in a population-based case-control study in Shanghai, China (411 cancer cases, 895 stone cases and 786 controls). We genotyped six single-nucleotide polymorphisms (SNPs), four in ESR1 (rs2234693, rs3841686, rs2228480 and rs1801132) and two in ESR2 (rs1256049 and rs4986938). In all participants, the ESR1 rs1801132 (P325P) G allele was associated with excess risks of bile duct [odds ratio (OR) = 1.7, 95% confidence interval (CI) 1.1-2.8] and ampulla of Vater cancers (OR = 2.1, 95% CI 0.9-4.9) compared with the CC genotype. The association with bile duct cancer was apparent among men (OR = 2.8, 95% CI 1.4-5.7) but not among women (P-heterogeneity = 0.01). Also, the ESR2 rs4986938 (38 bp 3' of STP) GG genotype was associated with a higher risk of bile duct cancer (OR = 3.3, 95% CI 1.3-8.7) compared with the AA genotype, although this estimate was based on a small number of subjects. None of the other SNPs examined was associated with biliary tract cancers or stones. False discovery rate-adjusted P-values were not significant (P > 0.1). No association was found for ESR1 haplotype based on four SNPs. These preliminary results suggest that variants in ESR genes could play a role in the etiology of biliary tract cancers, especially bile duct cancer in men.

Intra-individual variation in serum C-reactive protein over 4 years: an implication for epidemiologic studies

BACKGROUND

Data on long-term intra-individual variability in high-sensitivity C-reactive protein (hsCRP) are needed to determine whether one measurement adequately reflects usual levels in prospective studies of on the etiology of cancer and other chronic diseases; when not reflective, the ability to statistically detect modest to moderate associations is reduced. The authors estimated the size of this source of variability and consequent attenuation of the relative risk (RR).

METHODS

High-sensitivity C-reactive protein (hsCRP) concentration was measured using a high-sensitivity immunoturbidometric assay in sera collected at years 2, 4, and 6 from 50 men in the placebo arm of the Prostate Cancer Prevention Trial (PCPT). After natural logarithm-transformation of hsCRP, analysis of variance was used to estimate the within- and between-individual variances from which the intra-class correlation coefficient (ICC) was calculated.

RESULTS

The observed RR due to an ICC < 1 was calculated by e((ln true RR*ICC)) for a range of true RRs. The 4-year ICC was 0.66. Measuring hsCRP once and assuming no other error, if the true RRs were 1.50, 2.00, and 3.00 when comparing high with low concentration, then the observed RRs would be 1.31, 1.58, and 2.06, respectively.

CONCLUSION

Investigators planning to measure hsCRP only once should design adequately sized studies to preserve inferences for hypothesized modest to moderate RRs.