Purification and Characterization of Carcino-embryonic Antigens of the Human Digestive System

Abstract

IN previous studies from this laboratory, at least two common tumour-specific antigens, or antigenic determinants, were demonstrated to be present in adeno-carcinomata of the human colon¹. Subsequent investigations demonstrated identical antigens in all malignant tumours of the entodermally derived epithelium of the gastrointestinal tract, liver and pancreas, as well as in foetal gut, liver and pancreas obtained between two and six months of gestation². These carcino-embryonic antigens (CEA) were absent from all other normal, malignant or otherwise diseased adult tissues and all other foetal tissues tested. It was suggested that the carcino-embryonic antigens may represent cellular constituents which are repressed during the course of differentiation of the normal epithelium of the digestive system and reappear in the corresponding malignant cells by a process of derepressive dedifferentiation. Preliminary investigations with tumour tissue extraction in 0.6 molar perchloric acid led to the conclusion that the CEA were protein-polysaccharide complexes, and immunological data suggested that the tumour-specific antigenic determinants contained carbohydrate components^1,3.