Transplantable choriocarcinoma of rats induced by fetectomy and its biological activities.

Eight cases of choriocarcinoma were induced in WKA female rats by simple fetectomy without viral inoculation or administration of chemical carcinogens. Among them, one line has been successfully subcutaneously transplanted over 10 generations in syngeneic rats and this line was designated as RCHO. The histological appearance of RCHO consisted of trophoblastic giant cells and small basophilic tumor cells, which resembled normal rat placenta. RCHO possessed marked mammotropic and lactogenic activities in female recipients and induced atrophy of the testes in male recipients.