Currently, hypermethylation in promoter regions of some important tumor suppressor genes that cause gene expression inhibition has been identified in colorectal cancer cells (de Vallière et al., 2015), such as Cyclin-dependent kinase inhibitor 2A (CDKN2A) (Bihl et al., 2012), DNA mismatch repair protein Mlh1 (MLH1) (Cunningham et al., 1998), and Adenomatous polyposis coli protein (APC) (Liang et al., 2017). Here, CDKN2A is linked to colorectal cancer.