AFP and embryonal carcinoma: The other components may show aberrant differentiation toward extraembryonic and/or somatic features: yolk sac tumors stain for alpha fetoprotein (AFP) and glypican 3; choriocarcinomas are composed of mononucleated (cytotrophoblastic) and multinucleated (syncytiotrophoblastic) cells that stain for HCG; and embryonal carcinomas stain for CD30.