CDKN2A and colorectal carcinoma: The aberrant methylated genes in tumor tissue are commonly involved in aspects of cell function such as cell cycle regulation (CDKN2A (also known as p16) and IGF2), DNA mismatch repair (MLH1 and MGMT), apoptosis (DAPK1), cell adhesion (CDH1) and signal transduction (APC and WIF1) in CRC [4–10].