[Carcino-fetal antigens].

Among various kinds of tumor markers, alpha-fetoprotein (AFP) and carcinoembryonic antigen (CEA) are very important and widely used in the clinical medicine. AFP is a specific marker for diagnosis of hepatocellular carcinoma (HCC). AFP is a glycoprotein composed of 590 amino acid residues and has one asparagine-linked sugar chain at the 232nd position from N-terminal of the AFP molecule. A difference exists between the sugar chain of HCC AFP and the chain from a cirrhotic patient. This difference is easily detected by a lectin-binding analysis using LCA or PHA-E4. This technique enabled us to predict a risk of tumor occurrence in patients with a high probability of HCC development. Exciting progress in molecular biology has been made in the field of AFP and CEA research. The gene structures and the regulatory mechanism of synthesis of AFP and CEA has been elucidated successively. These results may provide a clue to the solution of the mechanism of carcinogenesis and may provide more sensitive tools for detection of tumors as well as practical therapies.