Serum CEA level is the most accurate indicator of CRC recurrence following primary curative treatment (Duffy, 2001), and the positive association of elevated serum CEA with more advanced TNM stage and worse prognosis in CRC patients has been documented previously (Nicholson et al., 2015; Saito et al., 2016; Huang et al., 2018). Here, CEACAM5 is linked to colorectal carcinoma.