NTRK1 and neuroblastoma: TrkAIII oncogenic activity (NIH3T3 cell transformation and promotion of primary and metastatic tumorigenicity in NB models), furthermore, is similar to that of the TrkA-fusion oncogene TrkT3 [25], confirming TrkAIII to be a splice variant oncogenic equivalent of TrkA-fusion oncogenes and also the engineered D4 domain-deleted TrkA oncogene [31,37,38].