PTEN and central nervous system cancer: Although gliomas induced by transplantation of non-fluorescent Pten-deleted Ras-driven murine glioma cells showed recruitment of proliferating host brain cells into the glioma mass (Figure S5f,h), the overall amount of recruited cells into Ras-driven tumors and the number of tumors that showed large regions of recruitment was significantly less than that seen with the hPDGFb-induced gliomas (Figure 2g).