However, clinical trials that aim at the Notch pathway showed that the Notch signaling inhibitor, γ-secretase inhibitor (RO4929097), had little clinical efficacy as a single agent in GBM [4, 5], although it indeed produced inhibitory activity of Notch signaling in tumor cells and inhibited CD133+ neurosphere formation [5]. This evidence concerns the gene PROM1 and neoplasm.