Fig. 6. Effects of K1014chim expression on tumor development in mice subjected to a skin carcinogenesis protocol (DMBA/TPA protocol). 20 mutants and 20 wild-type mice (gender and age matched) were subjected to the protocol. We used mutants that were congenic with the C57Bl/6 background for this experiment. All mice were treated once with DMBA (50 µg/mouse), followed by TPA treatment (20 µg/mouse) once a week for 25 weeks. (a) K1014 mutants developed papillomas earlier than control mice and on average carried 2-3 times as many tumors per mouse. (b) The percentage of tumor-free mutant mice declined more rapidly throughout the 25-week period than the percentage of tumor-free wild-type controls. For example, 10 weeks into the TPA treatment about 50% of the mutants were tumor free, whereas 95% of the wild-type controls had not developed tumors (P<0.05).