Immunohistochemical Type Distinction of a‐Fetoprotein in Various a‐Fetoprotein‐secreting Tumors

In order to clarify the histogenesis of a‐fetoprotein(AFP)‐secreting tumor tissues, formalin‐fixed, paraffin‐embedded serial sections of 148 tumors in various organs were examined by the peroxidase‐antiperoxidase method for AFP, and paradoxical concanavalin A staining. Yolk sac‐type AFP was found in yolk sac tumors, embryonal carcinomas, solid teratomas, (yolk sac) endodermal cell tumors, adenocarcinomas (stomach, ovary or lung) and metastatic liver cancers. Hepatic‐type AFP was demonstrated in hepatocellular carcinomas, hepatoblastomas, solid teratomas and a stomach cancer. Yolk sac‐type AFP was observed in the neighboring liver cells of metastatic liver cancers without relation to the type of AFP in primary cancers. The results from serum analyses of preoperative tumor‐bearing patients (68 cases) were coincident with those from immunohistochemical stainings.