Neoplastic transformation of canine embryo cells in vitro by N-methyl-N'-nitro-N-nitrosoguanidine.

A cell line derived from a normal beagle embryo was treated in vitro with various levels of N-methyl-N'-nitro-N-nitrosoguanidine or dimethyl sulfoxide (control). Cells treated only with the carcinogen underwent morphologic alteration in vitro, and one of these altered cell lines produced tumors subcutaneously when injected into NIH nude mice. The tumorigenic transformed line formed larger cell aggregates and grew in this aggregate form when suspended in liquid growth medium above an agar base.