• Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, Bethesda, Maryland 20852, USA.

BACKGROUND: Inflammation has been hypothesized to increase prostate cancer risk. Tumor necrosis factor (TNF) is an important mediator of the inflammatory process, but the relationship between TNF variants and prostate cancer remains unclear.

METHODS: We examined associations between six TNF single nucleotide polymorphisms (SNPs) (rs1799964, rs1800630, rs1799724, rs1800629, rs361525, rs1800610) and prostate cancer risk among 2,321 cases and 2,560 controls from two nested case-control studies within the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO, n = 2,561, 5 SNPs) and the Cancer Prevention Study II Nutrition Cohort (Nutrition Cohort, n = 2,320, 6 SNPs). Odds ratios and 95% confidence intervals were estimated for individual SNPs and haplotypes in each cohort separately and in pooled analyses.

RESULTS: No TNF SNP was associated with prostate cancer risk in PLCO (P-trend > or = 0.16), while in the Nutrition Cohort, associations were significant for 2 highly correlated variants (rs1799724, 1800610, r2 = 0.95; P-trend = 0.04 and 0.02, respectively). In pooled analyses, no single SNP was associated with prostate cancer risk (P-trend > or = 0.08). After adjustment for multiple testing, no SNP was associated with prostate cancer risk in either cohort individually or in the pooled analysis (P-trend all > or = 0.10). Haplotypes based on 5 TNF SNPs did not vary by case/control status in PLCO, but showed marginal associations in the Nutrition Cohort (global P = 0.06) and the pooled analysis (global P = 0.05).

CONCLUSIONS: Despite somewhat suggestive haplotype results, overall our study does not support an association between TNF variants and prostate cancer risk.