NTRK1 and cancer: NTRK1/2/3 genes encode TrkA/B/C proteins, respectively, and help regulate pain, proprioception, appetite, and memory.1,2 Chromosomal rearrangements leading to NTRK fusion genes then result in constitutive activation of Trk proteins which then act as oncogenic drivers of tumor growth.3,4NTRK gene fusions are a relatively rare occurrence with a prevalence of 0.3% across 45 cancers with the highest prevalence observed in salivary gland tumors (2.28%).3