Limitations of our study are the small numbers of rats treated with DNAse I/proteases that did not allow to show a statistically significant reduction in the number of tumors as compared to rats receiving both DMH and SW480 injection; the fact that we only microdissected a single tumor from each group of rats and that we did not evaluate that these human genes (mutated K-Ras and RAB) transferred to rat colon tumors were actually expressed. The gene discussed is KRAS; the disease is colonic neoplasm.