KLK3 and Familial prostate cancer: Genetic factors are among the many elements that influence an individual's PSA level, and indeed many aspects of prostate cancer biology.[14] There are multiple reports of various single‐nucleotide polymorphisms (SNPs) correlating with serum PSA levels.[15, 16, 17, 18, 19, 20] One SNP that repeatedly shows this connection is rs17632542 on chromosome 19 in the kallikrein‐3 gene leading to lower serum PSA levels than expected.[17, 18, 19, 21, 22, 23] The genetic variant alters a codon ATT to ACT leading to an amino acid substitution of an isoleucine to a threonine at position 179 (I179T).