Lectin affinity electrophoresis of alpha-fetoprotein in cancer diagnosis

Lectin affinity electrophoresis of serum alpha-fetoprotein (AFP) was carried out on samples obtained from patients with benign and malignant diseases and on cord blood, and separated AFP bands were detected by antibody-affinity blotting. The following major bands were identified by determination of kinetic constants: AFP-C1 and -C2 with concanavalin A, AFP-L1, -L2 and -L3 with Lens culinaris agglutinin A, AFP-P1, -P2, -P3, -P4 and -P5 with erythroagglutinating phytohemagglutinin, and AFP-A1, -A2 and -A3 with Allomyrina dichotoma lectin. AFP bands with the lowest number had either low or no affinity and those with higher numbers had higher affinities for respective lectins. AFP from cord blood and chronic liver disease was characterized by the predominance of AFP-C2, AFP-L1, AFP-P2 and AFP-A3. Hepatocellular carcinoma was differentiated from the benign liver disease by increased proportions of AFP-L3 and AFP-P4. Extrahepatic tumors had additional increases of AFP-C1, AFP-L2, AFP-P5 and AFP-A1 (or slow-migrating AFP-Als, particularly in yolk sac tumor).