Circadian genes and risk of prostate cancer in the prostate cancer prevention trial.

Circadian genes have been considered as a possible biological mechanism for the observed relationship between circadian rhythm disruptions and increased risk of hormone-related cancers. In the current study, we investigated the relationship between circadian gene variants and prostate cancer risk and whether reducing bioavailable testosterone modifies the circadian genes-prostate cancer relationship. We conducted a nested case-control study among Caucasian men in the Prostate Cancer Prevention Trial (PCPT), a randomized placebo-controlled clinical trial to assess if finasteride (an androgen bioactivation inhibitor) could prevent prostate cancer.