Immunohistochemical localization of murine stage-specific embryonic antigens in human testicular germ cell tumors.

Monoclonal antibodies raised against and/or recognizing stage-specific antigens on preimplantation mouse embryos and stem cells of murine teratocarcinoma were used to localize these antigens immunohistochemically on human testicular germ cell tumors. SSEA-1, the antigen found on mouse embryonal carcinoma (EC) cells and embryonic cells from the 8-cell stage embryo onward, including the fetal primordial germ cells, was detected on yolk sac carcinoma components of human tumors, but not on EC cells. SSEA-3, the antigen found on follicular ova, fertilized eggs, early cleavage stage embryonic cells, and visceral endodermal cells of the mouse embryo, but not on mouse EC cells, was detected on human EC cells. Both antigens were found on the cell surface of fetal testicular germ cells but not in the seminiferous tubules of adult human testes. These data point out differences between human and murine EC cells suggesting that human EC cells correspond developmentally to a less mature embryonic cell than the murine EC cells. The possible histogenesis of human germ cell tumors from primordial and/or fetal germ cells is briefly discussed.