CEACAM5 and colorectal carcinoma: The AUC for CEA assay was 0.688 (95% CI: 0.644-0.730), and the optimal cut-off value was 5 ng/ml, providing a sensitivity of 37.16% and a specificity of 88.75%, which was markedly lower than that for exosomal CRNDE-h (P < 0.001), indicating that exosomal CRNDE-h was superior to CEA in distinguished CRC from colorectal benign disease and NC (Figure 6B).