SMAD4 and neoplasm: Previous studies have identified the loss of CDKN2A on chromosome 9 and SMAD4 on chromosome 18 as important drivers of pancreatic carcinogenesis and progression, with homozygous deletion being a major cause of inactivation of these two key tumor suppressor genes.[63] In this study, we first confirmed the presence of CDKN2A‐ and SMAD4‐related homozygous deletions in PDAC cells using TGS.