[Immunohistochemical study of placental alkaline phosphatase in seminoma]

Indirect immunoperoxidase staining was carried out on seminomatous tumors of testes (22 specimens) using anti-placental alkaline phosphatase antibody to search for the usefulness of placental alkaline phosphatase as a tumor marker. All of the seminomas showed positive staining mainly on the cell surface. However, the normal testes and non-seminomas showed negative staining. Of interest, normal tissues outside the tumor mass showed positive staining. This phenomenon is considered to be suggestive of carcinoma in situ. Immunohistochemical study of placental alkaline phosphatase on the seminomas is a useful method for histopathological diagnosis and may be useful for understanding the pathogenesis of the tumor.