MSH2 and gastric cancer: To generate such models, we combined the MYC transposon–transposase system with a CRISPR vector co-targeting p53 and the mismatch repair gene Msh2. This approach allows for direct comparison of isogenic MSI (MYC-p53−/−-Msh2−/−) and microsatellite stable (MSS) (MYC-p53−/−) gastric cancers.