In a recent study of 44 samples of ALK-positive NSCLC, the most commonly seen mutational signature was the clock-like signature (SBS1) whereby C > T transition occurred most frequently, followed by C > A transitions.59 In genetically engineered mouse models of lung adenocarcinoma, EGFRL858R-induced lung adenocarcinomas show significant enrichment for C > T transitions compared to KRAS-driven NSCLC.60 This finding was later corroborated by a separate effort that analyzed 47 EGFR-driven lung adenocarcinoma samples from the Cancer Genome Atlas.61 Here, KRAS is linked to lung adenocarcinoma.