Growth patterns and chromosome constitutions of human malignant tumours after long-term serial transplantation in nude mice.

Five human malignant tumours, heterotransplanted to athymic nude mice, have been re-investigated after long-term serial transplantation, and their growth patterns and chromosomal constitutions compared with their early appearance. After 27-56 passages over 3 1/2--5 1/2 years, all of the tumours--two adenocarcinomas of the colon, two malignant melanomas, and one Burkitt's lymphoma--retained the cytological and histological appearance of the inoculated human material. All the mitoses observed in the chromosome studies were of human karyotype. The fact that no total chromosomal species shift, no interspecies hybridization, and no changes in biological properties appeared--as observed in some other heterotransplantation systems--would indicate that human tumours grafted to nude mice are more suitable models in, e.g., studies concerning cancer chemotherapeutics.