Sensitivity to two-stage carcinogenesis of SENCAR mouse skin grafted to nude mice.

SENCAR mice are extremely susceptible to two-stage skin carcinogenesis, while BALB/c mice are relatively resistant. Skin grafts to BALB/c nude mice were performed with full-thickness skin from SENCAR and BALB/c donors, and tumor formation was monitored in grafted skin, surrounding host skin, and intact SENCAR, BALB/c and nude mice. Initiation was accomplished by exposure to 20 micrograms dimethylbenz(a)anthracene and promotion by repeated exposure to 12-O-tetradecanoylphorbol-13-acetate. SENCAR skin retained a high sensitivity to carcinogenesis when grafted to nude hosts, whereas BALB/c skin remained resistant. The donor type did not influence the tumor yield in surrounding nude host skin. The rate of tumor regression was not altered in SENCAR skin grafts on nude mice relative to intact SENCAR skin. These results indicate that the unusual sensitivity of SENCAR epidermis to chemical carcinogenesis is not due to altered systemic factors but is a property of the skin itself.