P2RX4 and cancer: Regarding cancer, studies have been performed on several cancer-derived cell lines, reporting different roles in cell proliferation for P2X5R, P2X7R, P2Y1R, P2Y2R, and P2Y11R in prostate cancer; P2X7R and P2Y2R in ovarian cancer; P2X7R, P2Y2R, P2Y6R, P2Y11R, and P2Y12R in breast cancer; and P2X4R, P2X7R, P2Y2R and P2Y6R in lung cancer [19].