Abstract
Three lines of transplantable chorionic tumors have been established. They were numbered m-673, m-731 and m-786. At present they are transplanted over 25 generations and in this paper the morphology of both m-673 and m-731 was described. Biological behavior and morphological characteristics of parent tumors resembled those of the human choriocarcinoma. Histological appearance of these two lines were similar to each other and with the advance of generations of transplantation, PAS positive substance in the cytoplasm gradually decreased. The specific enzyme, 3β-ol-dehydrogenase-isomerase system of normal rat placenta on this tumor (m-673) was detected.
