In in vitro and in vivo experiments, NK-1R antagonists blocked (in a concentration-dependent manner) the proliferation of tumor cells by inducing apoptotic mechanisms [13,18,27,37,50,61,62]; inhibiting the basal kinase activity/phosphorylation of Akt [30]; increasing the expression of p21 and p27 (cell cycle regulatory proteins) and inducing G1/S cell cycle arrest [63]. The gene discussed is TACR1; the disease is neoplasm.