Oncogenic KRAS and p53 loss drive gastric tumorigenesis in mice that can be attenuated by E-cadherin expression

Gastric adenocarcinoma (GA) is the third leading cause of cancer-related death worldwide, but no models exist to readily investigate distant metastases which are mainly responsible for mortality in this disease. Here we report the development of a genetically engineered mouse model of GA tumorigenesis based on KrasG12D expression plus inactivation of E-cadherin (Cdh1) and p53 in the gastric parietal cell lineage. Intestinal and diffuse gastric tumors arise rapidly in this model, which displays a median survival of 76 days. Tumors occur throughout the stomach with metastases documented in lymph nodes, lung and liver. Mice otherwise identical but retaining one wild-type Cdh1 allele exhibited longer survival with only 20% penetrance of invasive tumors and no apparent lung or liver metastases. Notably, increased RAS activity and downstream MAPK signaling was observed in stomachs only when E-cadherin was absent. This model offers a valuable tool to investigate GA subtypes where RAS/MAPK pathway activation and E-cadherin attenuation are common.

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