For real‐time PCR detecting CEA mRNA in CRC patients, the prior probabilities for sensitivity and specificity were established at 0.33–0.667 and 0.697–0.864, respectively [15, 16, 17, 27, 39, 40, 41, 42], The prior probability for the positive rate of IFCCs in CRC patients was set between 0.08 and 0.379, derived from relevant studies [15, 16, 17, 25, 27, 39, 40, 41, 42, 43]. This evidence concerns the gene CEACAM5 and colorectal carcinoma.