Thus, we generated organoids derived gastric tumors arising in Tff1:CreERT2; KrasG12D; Pi3kCaH1027R; Tp53R172H (KPT) compound mutant mice in response to tamoxifen-dependent conversion of Kras and PI3K to their oncogenic isoform and simultaneous ablation of the p53 tumor suppressor gene (Eissmann, unpublished). This evidence concerns the gene KRAS and gastric neoplasm.