AFP and colorectal carcinoma: Currently, several serum markers such as carcinoembryonic antigen (CEA), carbohydrate antigen 19-9 (CA199), carbohydrate antigen 125 (CA125), carbohydrate antigen 242 (CA242) and alpha fetoprotein (AFP) have been applied for diagnosing and monitoring CRC in the clinic [3, 4].