To confirm the role of P2Y2R in in vivo tumor progression, nude mice were injected with control-shRNA-transfected MDA-MB-231 cells (MDA-MB-231-EV) or P2Y2R-shRNA-transfected MDA-MB-231 cells (MDA-MB-231-P2Y2R shRNA), and tumor volumes and body weights were measured every 3 days for 60 days. The gene discussed is P2RY2; the disease is neoplasm.