We identified the GBM cell line, GL261N (a derivative of the GL261 cell line), the GFAP-tv-a RCAS-PDGFA, shp53, shNF1 (RCAS) transgenic model13 and the ovarian cancer cell line, ID8, that generated tumors in the brain (GL261N and RCAS) and peritoneum (ID8) of mice expressing high levels of LIF (Supplementary Fig. 2a). The gene discussed is PDGFA; the disease is glioblastoma.