SMAD4 and gastric cancer: This combination specifically models human gastric cancers with chromosomal instability, which represents approximately 50% of human gastric adenocarcinomas and is characterized by aneuploidy, frequent copy number alterations, and mutations in TP53, KRAS, and SMAD4, typically associated with intestinal-type morphology and better prognosis than other subtypes (Comprehensive molecular characterization of gastricadenocarcinoma, 2014; Nemtsova et al., 2023; Maleki and Röcken, 2017).