[Immunological localization of alpha-fetoprotein in the proximal endoderm and its significance in extra-embryonic differentiation of teratocarcinomas in the mouse].

The ABC technique using a specific anti-mouse alpha-foetoprotein (AFP) serum permits identification of groups of extraembryonic proximal endoderm cells in certain teratocarcinomas. These AFP+ cells are always associated with trophoblastic and parietal endodermal patterns and structures. These observations strongly support the hypothesis of a common precursor to the extraembryonic tissues which appears during the first phases of egg development.