We chose dual inhibition of MEK and BRAF because this combination is the standard of care for BRAFV600E-mutant human lung adenocarcinoma (Planchard et al., 2016) and because in other genetically engineered mouse models driven by BRAFV600E example for thyroid cancer (McFadden et al., 2014), the combination of the two inhibitors is more effective than either one alone at inhibiting the MAPK pathway in vivo. Here, MAP2K7 is linked to lung adenocarcinoma.