CEACAM5 and carcinoma: An additional serological assay measures the serum levels of carcinoembryonic antigen (CEA), a member of a family of N-glycoproteins, that is overexpressed in a wide range of human carcinomas, including colorectal, gastric, pancreatic, lung, and breast carcinomas, and is shed into circulation [25, 27, 80, 82, 83, 89–93].