RET and non-small cell lung carcinoma: Additional targetable gene alterations in NSCLC include BRAF and HER2 mutations, as well as rearrangements in the RET proto-oncogene (RET), and fusions involving the neurotrophic receptor tyrosine kinase (NTRK) genes 1-3 (NTRK1, NTRK2, NTRK3) (24).