Afatinib restrains K-RAS–driven lung tumorigenesis

On the basis of clinical trials using first-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs), it became a doctrine that V-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog ( K-RAS ) mutations drive resistance to EGFR inhibition in non–small cell lung cancer (NSCLC). Conversely, we provide evidence that EGFR signaling is engaged in K-RAS–driven lung tumorigenesis in humans and in mice. Specifically, genetic mouse models revealed that deletion of Egfr quenches mutant K-RAS activity and transiently reduces tumor growth. However, EGFR inhibition initiates a rapid resistance mechanism involving non-EGFR ERBB family members. This tumor escape mechanism clarifies the disappointing outcome of first-generation TKIs and suggests high therapeutic potential of pan-ERBB inhibitors. On the basis of various experimental models including genetically engineered mouse models, patient-derived and cell line–derived xenografts, and in vitro experiments, we demonstrate that the U.S. Food and Drug Administration–approved pan-ERBB inhibitor afatinib effectively impairs K-RAS–driven lung tumorigenesis. Our data support reconsidering the use of pan-ERBB inhibition in clinical trials to treat K-RAS –mutated NSCLC.