CEACAM5 and colorectal carcinoma: Currently, available early screening methods for CRC include colonoscopy, fecal immunohistochemistry test (FIT), fecal occult blood test (FOBT), carcinoembryonic antigen (CEA), carbohydrate antigen 19–9 (CA19-9) (Bakhsh et al., 2022), and septin9 gene methylation blood test (Xiao et al., 2020).