NGF and neoplasm: In salivary adenoid cystic carcinoma, Schwann cell programs couple to tumour neurotrophin signalling; autophagic Schwann cells drive NGF–TrkA−mediated perineural invasion, indicating that glial−directed interventions (e.g., modulation of Schwann cell autophagy or adhesion programs such as NCAM1) may constrain neural tracking (75, 76).