Firstly, subjects homozygous for the C allele of rs7310505 in TXNRD1 had an OR of 0.88 for prostate cancer risk (95% CI = 0.78–1.00, p = 0.045) per 10 μg/l increase in serum Se concentration, whereas in subjects carrying the A allele (heterozygous or homozygous) no association was found (Pinteraction = 0.06). This evidence concerns the gene TXNRD1 and Familial prostate cancer.