Notch signaling plays a complex role in human malignancies. It can affect cell proliferation, differentiation and apoptosis either positively or negatively, depending on cell type. In the present study we measured the expression of Notch1 in clinical glioma specimens and investigated a possible association between Notch1 expression and World Health Organization grade. Ninety-eight gliomas plus adjacent normal tissue and 26 specimens of normal control tissue were collected, and expression of Notch1 mRNA and protein were assessed using quantitative real-time polymerase chain reaction, western blot and immunohistochemical analysis. We found that Notch1 mRNA and protein were expressed at higher levels in gliomas than in the adjacent tissue or in control brain tissue (p<0.05). Moreover, expression of Notch1 was closely associated with glioma progression, since expression levels increased from grade I to grade IV disease (p<0.05). Notch1 expression was also significantly associated with Karnofsky performance scale (KPS) score: Notch1 expression was significantly higher in patients with a lower KPS score (p<0.05). These findings confirm that Notch1 expression is upregulated in glioma and suggest it is related to tumor progression. If Notch1 plays an important oncogenic role in glioma progression, it may be a potential diagnostic and therapeutic target.
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