Chronic intra-prostatic inflammation and obesity are thought to influence prostate carcinogenesis. Thus, variants in genes in these pathways could be associated with prostate cancer risk.
We genotyped 17 common single nucleotide polymorphisms (SNPs) in RNASEL, TLR4, IL1B, IL6, IL8, IL10, TNF, CRP, ADIPOQ, LEP, PPARG, and TCF7L2 in 258 white prostate cancer cases and 258 matched controls nested in CLUE II. Single-locus analyses were conducted using conditional logistic regression. TagSNPs were selected in IL10, CRP, and TLR4 and haplotype analyses were done.
The A allele of IL10 -1082G>A (rs1800896), known to result in lower levels of this anti-inflammatory cytokine, was positively associated with risk (AG vs. GG, OR=1.69, 95% CI: 1.10–2.60; AA vs. GG, OR=1.81, 95% CI: 1.11–2.96; Ptrend=0.02). Associations of IL10 haplotypes with prostate cancer were explained by high linkage disequilibrium between two tagSNPs (rs1800890 and rs3024496) and -1082G>A. A TLR4 candidate SNP (rs4986790; AG/GG vs. AA, OR=0.60, 95% CI: 0.33–1.08; Ptrend=0.09), known to have decreased expression and be associated with lower circulating levels of inflammatory mediators, and tagSNP (rs10116253; CC vs. TT, OR=3.05, 95% CI: 1.11–8.41), but not haplotypes, were associated with risk. None of the other candidate SNPs or haplotypes was statistically significantly associated with risk.
Our prospective study suggests that genetic variation in IL10 and possibly TLR4 is associated with prostate cancer risk. Although none of the SNPs in the obesity genes tested was associated, this does not rule out a complex role of obesity and its metabolic consequences in prostate cancer etiology.