NTRK1 and non-small cell lung carcinoma: On the other hand, the NTRK1 gene fusion occurs with low incidence in several solid tumors, including NSCLC, colorectal cancer, intrahepatic cholangiocarcinoma, papillary thyroid cancer, spitzoid neoplasms, glioneuronal tumors, and sarcomas 25, 31, 32, 33, 34, 35, 36.