Previously it was shown that the arrangement of tPA, BDNF, TrkB, proBDNF, and p75NTR might be a diagnostic biomarker panel for MDD (27) and the combination of BDNF, FGF-2, TNF-α, and 5-HT may predict the efficacy of escitalopram therapy (70). Here, BDNF is linked to major depressive disorder.