In addition, high expression levels of the neurotrophic factors NGF, brain-derived neurotrophic factor (BDNF), neurotrophin (NT)-3, and NT-4 were observed in both NSCLC cell lines, and the injection of NGF in mice with lung tumors increased the size of the tumors and the expression of the pan-neuronal marker PGP9.5, Ki-67, and N-cadherin. Here, BDNF is linked to non-small cell lung carcinoma.