Other NTRK variant types, such as the NTRK1 in‐frame deletion (ΔTRKA) in acute myeloid lymphoma, the NTRK1 splice variant (TRKAIII) in neuroblastoma, TRKA overexpression in breast cancer, TRKB overexpression in neuroblastoma, and TRKC overexpression in small round cell tumor may possibly be related to tumorigenesis and cancer development.19, 20, 21. Here, NTRK1 is linked to breast cancer.