Cancer patients whose tumours harbour a gene fusion in the Neurotrophic Tyrosine Receptor Kinase genes 1, 2 or 3 (NTRK1, NTRK or NTRK3) are clinically recommended for treatment in the advanced and refractory setting with targeted therapy in the form of Tyrosine Receptor Kinase (TRK) inhibitors1. The gene discussed is NTRK1; the disease is cancer.