NTRK1 and lung carcinoma: Other studies detected TrkA fusions in 3.3% lung cancers, 0.5–2% colorectal cancers, < 12% papillary thyroid carcinomas, TrkA/B/C fusions in 7% pediatric gliomas, and TrkC fusions in 92–100% secretory mammary tumors [23, 24].