However, further augmenting PI3K pathway activation through heterozygous ablation of Pten in triple-mutant Tff1CreERT2;KrasLSL-G12D/+;Pik3caLSL-H1047R/+;Ptenflox/+ (referred to as Tff1CreERT2;KrasG12D/+;Pik3caH1047R/+;Ptendel/+ or KPP) mice increased the overall frequency of gastric tumors to 81%, and over two-thirds of the tumors in KPP mice had progressed to carcinomas. The gene discussed is PIK3CA; the disease is gastric neoplasm.