The gross pathology and histological features of tumours produced by inoculation of human cell lines into immune-deprived mice.

Tumours were raised in both congenitally athymic ('nude') Swiss mice and in neonatally thymectomized, Ara-C-protected, whole-body irradiated CBA mice by subcutaneous inoculation of cells from a variety of cultured human lines. In both types of animal, tumours tended to grow massively at the site of inoculation, with some infiltration of adjacent tissues but only rarely with evidence of metastatic spread. Tumours derived from Burkitt's lymphoma (BL) lines or from EB virus-transformed lymphoblastoid cell lines (LCL) were all classified as high grade malignant lymphomas with a limited range of appearances on conventional histological examination. In the material studied there were no consistent features distinguishing BL-derived from LCL-derived tumours. Cell lines originating from other haematopoietic malignancies tended to produce tumours interpreted as immunoblastic lymphomas though there were distinctive characteristics in some cases, such as highly convoluted or pleomorphic nuclei in the cells of some tumours derived from T-cell leukaemia lines and plasmacytoid differentiation in tumours originating from myeloma lines. Malignant cell lines of epithelial origin gave rise to tumours with the histological appearances of anaplastic carcinomas readily distinguishable from the high grade lymphomas produced by haematopoietic cells.