Objective

To examine whether a history of sexually transmitted infections (STIs) or positive STI serology is associated with prevalent and incident benign prostatic hyperplasia (BPH)/lower urinary tract symptoms (LUTS)-related outcomes in the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial.

Methods

Self-reported history of STIs (gonorrhoea, syphilis) was ascertained at baseline, and serological evidence of STIs (Chlamydia trachomatis, Trichomonas vaginalis, human papillomavirus (HPV)-16, HPV-18, herpes simplex virus type 2, human herpesvirus type 8 and cytomegalovirus) was detected in baseline serum specimens. We used data collected on the baseline questionnaire, as well as results from the baseline prostate-specific antigen (PSA) test and digital rectal examination (DRE), to define prevalent BPH/LUTS-related outcomes as evidence of LUTS (self-reported diagnosis of an enlarged prostate/BPH, BPH surgery or nocturia [waking ≥2 times/night to urinate]) and evidence of prostate enlargement (PSA > 1.4 ng/mL or prostate volume ≥30 mL) in men without prostate cancer. We created a similar definition of incident BPH using data from the follow-up questionnaire completed 5-13 years after enrolment (self-reported diagnosis of an enlarged prostate/BPH or nocturia), data on finasteride use during follow-up, and results from the follow-up PSA tests and DREs. We used Poisson regression with robust variance estimation to calculate prevalence ratios (PRs) in our cross-sectional analysis of self-reported (n = 32 900) and serologically detected STIs (n = 1 143) with prevalent BPH/LUTS, and risk ratios in our prospective analysis of self-reported STIs with incident BPH/LUTS (n = 5 226).

Results

Generally null results were observed for associations of a self-reported history of STIs and positive STI serologies with prevalent and incident BPH/LUTS-related outcomes, with the possible exception of T. vaginalis infection. This STI was positively associated with prevalent nocturia (PR 1.36, 95% confidence interval (CI) 1.18-1.65), prevalent large prostate volume (PR 1.21 95% CI 1.02-1.43), and any prevalent BPH/LUTS (PR 1.32 95% CI 1.09-1.61); too few men had information on both STI serologies and incident BPH/LUTS to investigate the associations between T. vaginalis infection and incident BPH/LUTS-related outcomes.

Conclusions

Our findings do not support associations of several known STIs with BPH/LUTS-related outcomes, although T. vaginalis infection may warrant further study.

Candidate gene and genome-wide association studies (GWAS) have identified 15 independent genomic regions associated with bladder cancer risk. In search for additional susceptibility variants, we followed up on four promising single-nucleotide polymorphisms (SNPs) that had not achieved genome-wide significance in 6911 cases and 11 814 controls (rs6104690, rs4510656, rs5003154 and rs4907479, P < 1 × 10(-6)), using additional data from existing GWAS datasets and targeted genotyping for studies that did not have GWAS data. In a combined analysis, which included data on up to 15 058 cases and 286 270 controls, two SNPs achieved genome-wide statistical significance: rs6104690 in a gene desert at 20p12.2 (P = 2.19 × 10(-11)) and rs4907479 within the MCF2L gene at 13q34 (P = 3.3 × 10(-10)). Imputation and fine-mapping analyses were performed in these two regions for a subset of 5551 bladder cancer cases and 10 242 controls. Analyses at the 13q34 region suggest a single signal marked by rs4907479. In contrast, we detected two signals in the 20p12.2 region-the first signal is marked by rs6104690, and the second signal is marked by two moderately correlated SNPs (r(2) = 0.53), rs6108803 and the previously reported rs62185668. The second 20p12.2 signal is more strongly associated with the risk of muscle-invasive (T2-T4 stage) compared with non-muscle-invasive (Ta, T1 stage) bladder cancer (case-case P ≤ 0.02 for both rs62185668 and rs6108803). Functional analyses are needed to explore the biological mechanisms underlying these novel genetic associations with risk for bladder cancer.

Background

Studies of related individuals have consistently demonstrated notable familial aggregation of cancer. We aim to estimate the heritability and genetic correlation attributable to the additive effects of common single-nucleotide polymorphisms (SNPs) for cancer at 13 anatomical sites.

Methods

Between 2007 and 2014, the US National Cancer Institute has generated data from genome-wide association studies (GWAS) for 49 492 cancer case patients and 34 131 control patients. We apply novel mixed model methodology (GCTA) to this GWAS data to estimate the heritability of individual cancers, as well as the proportion of heritability attributable to cigarette smoking in smoking-related cancers, and the genetic correlation between pairs of cancers.

Results

GWAS heritability was statistically significant at nearly all sites, with the estimates of array-based heritability, hl (2), on the liability threshold (LT) scale ranging from 0.05 to 0.38. Estimating the combined heritability of multiple smoking characteristics, we calculate that at least 24% (95% confidence interval [CI] = 14% to 37%) and 7% (95% CI = 4% to 11%) of the heritability for lung and bladder cancer, respectively, can be attributed to genetic determinants of smoking. Most pairs of cancers studied did not show evidence of strong genetic correlation. We found only four pairs of cancers with marginally statistically significant correlations, specifically kidney and testes (ρ = 0.73, SE = 0.28), diffuse large B-cell lymphoma (DLBCL) and pediatric osteosarcoma (ρ = 0.53, SE = 0.21), DLBCL and chronic lymphocytic leukemia (CLL) (ρ = 0.51, SE =0.18), and bladder and lung (ρ = 0.35, SE = 0.14). Correlation analysis also indicates that the genetic architecture of lung cancer differs between a smoking population of European ancestry and a nonsmoking Asian population, allowing for the possibility that the genetic etiology for the same disease can vary by population and environmental exposures.

Conclusion

Our results provide important insights into the genetic architecture of cancers and suggest new avenues for investigation.

Genome-wide association studies (GWAS) have mapped risk alleles for at least 10 distinct cancers to a small region of 63 000 bp on chromosome 5p15.33. This region harbors the TERT and CLPTM1L genes; the former encodes the catalytic subunit of telomerase reverse transcriptase and the latter may play a role in apoptosis. To investigate further the genetic architecture of common susceptibility alleles in this region, we conducted an agnostic subset-based meta-analysis (association analysis based on subsets) across six distinct cancers in 34 248 cases and 45 036 controls. Based on sequential conditional analysis, we identified as many as six independent risk loci marked by common single-nucleotide polymorphisms: five in the TERT gene (Region 1: rs7726159, P = 2.10 × 10(-39); Region 3: rs2853677, P = 3.30 × 10(-36) and PConditional = 2.36 × 10(-8); Region 4: rs2736098, P = 3.87 × 10(-12) and PConditional = 5.19 × 10(-6), Region 5: rs13172201, P = 0.041 and PConditional = 2.04 × 10(-6); and Region 6: rs10069690, P = 7.49 × 10(-15) and PConditional = 5.35 × 10(-7)) and one in the neighboring CLPTM1L gene (Region 2: rs451360; P = 1.90 × 10(-18) and PConditional = 7.06 × 10(-16)). Between three and five cancers mapped to each independent locus with both risk-enhancing and protective effects. Allele-specific effects on DNA methylation were seen for a subset of risk loci, indicating that methylation and subsequent effects on gene expression may contribute to the biology of risk variants on 5p15.33. Our results provide strong support for extensive pleiotropy across this region of 5p15.33, to an extent not previously observed in other cancer susceptibility loci.