Yolk-sac carcinoma of extra-embryonic origin in the 129 Sv/Sl mouse

Yolk-sac carcinoma develops spontaneously as a late occurrence in slow-growing teratoid tumors produced from transplanted 7-day mouse embryos

Seven-day embryos of BALB/c mice transplanted underneath the kidney capsule of adult syngeneic recipients form either benign teratomas or teratocarcinomas, which can be distinguished from one another histologically at 8 weeks post-embryonic transplantation. Embryo-derived (ED) teratomas were allowed to remain in the host for an additional period up to 1 year after embryo transplantation, to test their malignant potential. It was found that a considerable number of slow-growing small tumors derived from embryonic transplant give rise to parietal yolk-sac carcinomas. A proportion of these tumors contained foci of visceral yolk-sac and trophoblastic differentiation, which gradually disappeared in successive transplantations. We conclude that parietal yolk-sac carcinoma develops as a late event in some ED teratomas. These malignant tumors originate either from small foci of yolk sac originally included in the grafted embryo or, more likely, from the yolk sac formed from the differentiating embryonic stem cells.

Experimental rat model for human yolk sac tumor

The morphological and biological characteristics of experimentally induced rat yolk sac carcinomas (ysca) are compared to those of human yolk sac tumors. It is shown that the rat ysca shares many morphological and biological properties with its human counterpart although the cellular origin is probably different. Whereas the human yolk sac tumors are believed to be of germ cell origin, the rat visceral yolk sac-derived tumors are not. The hypothesis is formulated that the rat ysca are derived from multipotential cells different from germ cells, and which originate in the extra-embryonic membrane after displacement.