The quantification of Ki67 positive cells showed a 40.62% proliferation index in not-treated EGI-1 xenograft model; in xenografts treated with Panitumumab and Trametinib in monotherapy there was a decrease of Ki67 positive cells at 23.9% and 18.86% respectively, while the combined treatment further decreased the proliferation rate (15.65%)), consistent with the significant slow of tumor growth. This evidence concerns the gene MKI67 and neoplasm.