SMAD4 and pancreatic adenocarcinoma: SMAD4 inactivating mutations are common in gastric, colorectal, and pancreatic adenocarcinomas, whereas up to 20% of head and neck, bladder, cervical, and lung squamous carcinomas contain inactivating mutations in TGFβ signaling components like SMAD2, SMAD3, SMAD4, TβR1, or TβRII [8].