Attenuated proliferation and self-renewal ability of patient-derived GSCs on the blockade of Notch signaling. (A, B) Total RNA was prepared from primary tumor spheres on the 5th day in the presence of GSI or DMSO. And the expressions of Hes5 and Hes1 were measured by RT-PCR (A) and Real-time PCR (B), with human GAPDH as the reference control (n = 5, Hes5, P = 0.046, Hes1, P = 0.002). (C, D) Equal number of cells (1 × 105/ml) form brain tumor tissues were plated in the growth medium, the number of primary (n = 4, P = 0.008) (C) and secondary (n = 4, P = 0.041) (D) tumor spheres were counted 7 days after plating. *, P < 0.05, **, P < 0.01.