CNPY2 and colorectal carcinoma: In stage I-IV patients, the AUCs for distinguishing CRC patients from healthy controls on the basis of serum CNPY2 isoform 2 were 0.707 (95% CI: 0.649–0.765, P<0.001), 0.657 (95% CI: 0.595–0.719, P<0.001), 0.692 (95% CI: 0.632–0.751, P<0.001) and 0.625 (95% CI: 0.561–0.688, P<0.001), respectively (Figure 3B-D).The sensitivities and specificities of different serum CNPY2 isoform 2 levels for diagnosing stage I-IV patients are shown in Table 2.