siRNA downregulation of endogenous FIP200 protein inhibited cell proliferation and induced apoptosis in U-87MG human glioblastoma cells, immortalized human astrocytes, and human brain microvessel endothelial cells (MvECs) propagated in complete media, which are reactive and commonly used as a surrogate model of tumor-associated MvECs. The gene discussed is RB1CC1; the disease is glioblastoma.