TACR1 and osteosarcoma: Taken together, the data reported above show that NK-1R can be a potential new therapeutic target for the treatment of osteosarcoma because NK-1R antagonists (e.g., aprepitant) exert antitumor (antiproliferative, proapoptotic, antiangiogenic, antimetastatic, and tumor-shrinking) effects against osteosarcoma cells and tumors that overexpress NK-1R.