Reduction in Trp53 protein was also seen in Kras;Trp53−/−-targeted tumors relative to normal tissue and Kras;Stk11−/−-targeted tumors with a 70% and 75% reduction in Trp53 and Stk11 protein relative to normal lung tissue, respectively, confirming the corresponding genotypes in these heterogenous masses of tumor and stromal cells (Fig. 4d). This evidence concerns the gene KRAS and neoplasm.