Wild type U138, U138-P2X7 polyclone or U138-P2X7 clone glioma cells were subcutaneously inoculated into nude/nude athymic male mice in two amounts (1.4 × 106 or 3.0 × 106), and tumor development followed for fifteen days (Figure 7A, 7B). Here, P2RX7 is linked to central nervous system cancer.