KRAS and neoplasm: In our study, by testing KRAS and NRAS mutations in histologically relevant macrodissected zones according to pTNM, we observed the presence of (i) mutational intra-tumor heterogeneity with at least two co-existing KRAS and/or NRAS mutations within the same tumor areas and (ii) spatial intra-tumoral heterogeneity with coexistence within the same tumor of KRAS and/or NRAS mutated zones and WT zones.