To date, several potential blood-based DNA methylation biomarkers have been identified for CRC detection, including BCAT1, BMP3, C9orf50, CDKN2A, CLIP4, KCNQ5, MLH1, NDRG4, PRIMA1, SDC2, SEPT9, SFRP2, and VIM2,4 (Table 1). The gene discussed is CDKN2A; the disease is colorectal carcinoma.