Serum alpha-fetoprotein subfractions in hepatic malignancies identified by different reactivities with concanavalin A, lentil lectin or phytohemagglutinin-E.

Using a modified method of concanavalin A (Con A), lentil lectin (LCH) or phytohemagglutinin-E (PHA-E) affinity crossed-line immunoelectrophoresis (ACIE), we studied alpha-fetoprotein (AFP) subfractions in 69 sera, including 58 from patients with primary liver cancer and 11 from patients with hepatic metastasis of gastric cancer. We found that Con A non-reactive subfraction (type b) or LCH weakly-reactive subfraction (type B) was more frequently detected in metastatic liver cancer, as compared with liver cancer hepatoma. The amount of Con A non-reactive subfraction (type b) or of PHA-E reactive subfraction (type X) was significantly higher in case of metastatic liver cancer than in primary liver cancer. Since different affinities between AFP and lectins are due to the microheterogeneity in AFP sugar chain, our findings suggest that AFP in primary liver cancer and metastatic liver cancer is glycosylated in a different manner. It is also indicated that different patterns of AFP subfractions identified by the combination of Con A, LCH or PHA-E ACIE facilitate a differential diagnosis of these hepatic malignancies.