CEACAM5 and cancer: Various biomarkers have demonstrated clinical utility in early cancer detection and screening, such as alpha-fetoprotein (AFP), carcinoembryonic antigen (CEA), prostate-specific antigen (PSA), beta-human chorionic gonadotropin (β-Hcg), and carbohydrate antigen 19 − 9 (CA-19-9) [95].