In our dataset, KRAS G12R tumors had the highest incidence of comutations with the suppressor genes SMAD4, TP53, and CDKN2A, but this difference was only significant for SMAD4. It is plausible that the G12R mutation has less oncogenic potency than other common G12 mutations and can explain the overall rarity of this mutation in cancer in general.11KRAS G12R exhibits unique properties compared with other common G12 KRAS mutations. This evidence concerns the gene SMAD4 and cancer.