Growth of human tumor xenografts on chorioallantoic membrane of chick embryo.

We evaluated the success rates of transplantation and growth conditions of 33 human tumor xenografts transplanted on the chorioallantoic membrane of chick embryos. Eleven out of 14 renal cell carcinomas (78.6%), 7 out of 9 urothelial carcinomas (77.8%), 2 out of 3 testicular tumors (66.7%), an adenocarcinoma of the colon and an adenocarcinoma of the ovary but none of the 5 prostatic carcinomas were transplanted successfully. Histologically, carcinoma cells survived on the chorioallantoic membrane forming organoids the structure of which was well preserved. Several regions of the grafts frequently became necrotized. However, the viability of carcinoma nests was not influenced by the inflammatory changes surrounding necrotic tissues. Renal cell carcinomas survived diffusely with prominent angiogenesis. Immunostaining with anti-bromodeoxyuridine (BrdU) and Ki-67 monoclonal antibodies demonstrated a strong correlation between the %BrdU labeling index of the cancer cells on the chorioallantoic membrane and %Ki-67 index of the original tumors. No difference in %BrdU indexes was found between small and large cancer nests. Growth conditions remained constant for 8 days after inoculation. The growth potential of cancer nests surviving on the chorioallantoic membrane, which was identical to that of the original carcinomas, appeared to be unchanged during incubation. However, it might be difficult to exploit the chorioallantoic membrane for anticancer chemosensitivity tests except for renal cell carcinoma since few cancer cell nests were produced in spite of the high transplantation success rates.