MAP2K1 and adenocarcinoma: Stratification of identified mutations by IHC subgroup revealed a striking enrichment of oncogene mutations in adenocarcinoma-like LC tumors (85% of all oncogene mutations, affecting 63% of these cases), including all nine KRAS mutations and the single NRAS (G12D) and MAP2K1/MEK1 (K57N) mutations (Figure 1A, Supplementary Tables S2 and S3).