However, many of the well-known serum cancer-associated biomarkers, such as carcinoembryonic antigen (CEA), cancer antigen 125 (CA125), cancer antigen 242 (CA242) and cancer antigen 19-9 (CA19-9), are not sensitive and specific enough for screening GC and EJA 15,16. The gene discussed is CEACAM5; the disease is cancer.