In the NCCN guidelines, the recommended genes for genetic testing in most patients with advanced NSCLC include ALK, BRAF, EGFR, KRAS, MET, NTRK1/2/3, RET and ROS1. The broad genomic testing can be used to assess mechanisms of drug resistance in patients who have relapsed after the targeted therapies, to distinguish primary lung cancer from intrapulmonary metastasis, and to help determining suitability for certain molecular-driven clinical trials (2). The gene discussed is KRAS; the disease is lung cancer.