The mutational profile studies on IPNB have reported that diverse cancer driver mutations are frequently observed, including KRAS, TP53, STK11, CTNNB1, APC, SMAD4, and GNAS. Type 1 IPNBs show higher mutation rates of KRAS, GNAS, and RNF43, whereas type 2 IPNBs have higher TP53 and SMAD4 mutation rates (81, 82). The gene discussed is SMAD4; the disease is cancer.