NTRK1 and neoplasm: The NGF-TrkA pathway induces p75NTR proteolytic processing and the release of the soluble p75NTR intracellular domain (ICD), which is central to AKT signaling and CSCs sustained proliferation in several tumor types [76,77], suggesting that the generation of the ICD domain is crucial for the NGF/TrkA pro-oncogenic pathway [39].