In salivary ACC, SCs have been shown to promote PNI by inducing the epithelial-to-mesenchymal transition (EMT) and the Schwann-like differentiation of tumor cells through the brain-derived neurotrophic factor (BDNF)–neurotrophic receptor tyrosine kinase 2 (NTRK2/TrkB) pathway [71]. This evidence concerns the gene BDNF and neoplasm.