Heterotransplantation of two human tumours in athymic mice and asplenic-athymic mice.

The growth in athymic mice (Balb/c nu/nu mice) and athymic-asplenic mice (BALB/c nu/nu Dh/ + "lasat" mice) of two human tumour lines (one nasopharyngeal carcinoma and one testicular germ cell tumour), established in athymic mice, were compared. No significant difference in take rate was observed: 13 of 16 inocula grew in athymic mice and 11 of 12 inocula in lasat mice. Estimated by the square root of the relative tumour size related to time, the tumour growth was slightly, but insignificantly, less in lasat mice than in athymic mice. When the transplants removed from either athymic or lasat were compared by light microscopical examination, each of the two tumours demonstrated a similar appearance. The atypic mice prospered, while the lasat mice failed to thrive in similar laboratory surroundings. Thus this study does not confirm that heterotransplantation of human solid tumours on lasat mice is preferable to transplantation in athymic mice.