To address the functional relevance of the 3 main deregulated pathways (RTK/Ras/PI3K, p53, Rb) in glioblastoma, we assembled a panel of 11 small molecule compounds either inhibiting the RTK/Ras/PI3K and Rb pathway, or reactivating the p53 pathway (Supplementary Table S2). The gene discussed is RB1; the disease is glioblastoma.