Using the well-established KrasG12D; Trp53fl/fl (KP) mouse model of lung adenocarcinoma (Jackson et al., 2005), we created a Msi2-knockout lung adenocarcinoma model and found that deletion of Msi2 at initiation significantly impaired tumor incidence, reduced tumor burden and progression, and cumulatively led to a doubling of median survival. This evidence concerns the gene MSI2 and lung adenocarcinoma.