Transplantability and biological behavior of a rapidly growing secondary Morris hepatoma

Transplantable hepatomas have a special importance in cancer research because most are well-differentiated and grow at widely differing rates. A simple and reproducible technique was developed to transplant the rapidly growing Morris hepatoma 9618A2 from a subcutaneous to an intrahepatic site. The tumor has been maintained for over 80 successive transplant generations by inoculating Buffalo rats subcutaneously. The hepatoma, transplanted many times from the subcutaneous site to the liver, was examined histologically on various occasions. By varying inoculum size, growth of the hepatocarcinoma could be controlled. Throughout transplantation, the donor animals were bled without causing the death of the animal. Histological studies revealed that the tumor, when transplanted intrahepatically, remains a highly differentiated neoplasm with no observable morphological changes.