We used a panel of KRAS-mutant NSCLC cell lines to demonstrate that clinically relevant RAS/MAPK inhibitors adagrasib (G12Ci) and trametinib (MEK1/2i) reduced carboxymethylation and destabilized PP2A heterotrimers and that combination treatment with a PP2A molecular glue, RPT04402, restabilized PP2A heterotrimers. This evidence concerns the gene MAP2K1 and non-small cell lung carcinoma.