For example, NPAS2, homologous to CLOCK and regulating the cell cycle, is associated with prostate cancer risk,43,48 aggressiveness,44,45 and progression.49 NPAS2:BMAL1 heterodimers have been shown to regulate the expression of the proto-oncogene and Wnt target c-MYC, highlighting a potential mechanism of NPAS2 in tumorigenesis.35 In addition, other circadian clock genes including RORα1 and PER3 have associated with prostate cancer. This evidence concerns the gene PER3 and Familial prostate cancer.