Actually, Ca2+ signals following UTP/ATP stimulation in MDA-MB-231 was significantly but not completely reduced by P2Y2R siRNA, which is possibly due to the incomplete knock-down efficiency of P2Y2R. Various studies have also reported that P2Y2R is most consistently expressed by tumor cells, however the role of P2Y2R on the tumor growth is controversial depending on tumor types [9–15]. The gene discussed is P2RY2; the disease is neoplasm.