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, 3αdiol 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 × 10^-3) and bioavailable testosterone (P < 6.3 × 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.