Growth and regression of human tumor cell lines in congenitally athymic (rnu/rnu) rats

Athymic rats were inoculated with cells from nine human tumor tissue culture cell lines. Tumor growth was seen with seven of the cell lines; histologically, the tumors resembled the tumors from which the cell lines were originated. Only one cell line--a malignant melanoma--grew progressively. The remaining sex cell lines grew to a short period of time and then regressed.