In addition to the involvement of SP in depression, the NK-1 receptor antagonist L-733,060 has been used as an antidepressive agent [34, 35], and it has been demonstrated that this antagonist has antitumor activity against human glioma, neuroblastoma, melanomas, retinoblastoma, and pancreatic carcinoma cell lines [18, 20, 21, 23–25, 127]. Here, TACR1 is linked to major depressive disorder.