The sensitivities of methylated ADHFE1, SDC2 and PPP2R5C, and the combination of these three genes for CRC detection were 84.6%, 69.2%, 69.2% and 84.6%, respectively, and their specificities were 100%, 92.3%, 100% and 92.3%, respectively (Table 2). The gene discussed is SDC2; the disease is colorectal carcinoma.