ROS1 and non-small cell lung carcinoma: Mutations in EGFR, ALK, BRAF, NTRK, MET, RET, ROS1, KRAS (Kirsten rat sarcoma virus), HER2 (human epidermal growth factor receptor 2) genes have all been found to be expressed in NSCLC and have targeted therapies inhibiting the abnormal proteins for which these mutated genes encode.