CLOCK and Familial prostate cancer: 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.