CCNG1 and Familial prostate cancer: Of considerable relevance and conceptual support for this highly simplified model of the Cyclin G1 Axis are comparative screens identifying genetic variants in cell cycle and checkpoint control pathways that confer particular susceptibility to aggressive cancers: Notably, CCNG1, CDK2, CDK5, and MDM2 were identified among the Top-7 genes with variants associated with aggressive prostate cancer (Kibel et al., 2016).