Among these, the serological assays that have been approved are carcinoembryonic antigen (CEA) for colorectal cancer, cancer antigen 125 (CA125) for ovarian cancer, CA19.9 for pancreatic and gastric cancer, and prostate-specific antigen (PSA) for prostate cancer 18-20. The gene discussed is CEACAM5; the disease is prostate carcinoma.