Great effort has been dedicated to the search of sensitive and specific markers of the disease and up to now, carcinoembryonic antigen (CEA) and the gastrointestinal cancer-associated carbohydrate antigen (CA 19-9) are the most widely applied markers in gastrointestinal malignancies, e.g., CRC or pancreatic cancer [3-7]. The gene discussed is CEACAM5; the disease is colorectal carcinoma.