NOTCH1 and glioblastoma: From an analysis of the expression level of HIF-1α (with or without Notch1 expression), which was based on the staining intensity score judged by an expert pathologist who analyzed the samples in a blinded fashion, the expression level of HIF-1α in GBM patient samples was positively correlated with Notch1 expression status (Notch1-negative, 1.25 ± 0.50; Notch1-positive, 2.43 ± 0.53; p < 0.05) (Fig. 6H).