CCNA2 and cancer: Although there is limited understanding of the detailed molecular mechanisms so far, there are several papers that have provided evidence for mechanisms for IGFBP7 involvement in suppression of cancer, one of which is the critical mechanism of inactivation of IGFBP7 expression by aberrant hypermethylation (93); a second mechanism has been proposed to be via regulation of p21 and cyclin A/CDK-2 activity and resulting induction of apoptosis (137).