Objective  To explore the expression pattern of Notch1 intracellular domain (ICD) in astrocytic tumors and its clinical significance.    Methods  Notch1 ICD mRNA was detected in 12 fresh-resected astrocytic tumors of various grades after pathological diagnosis and 2 normal cerebral tissues in Daping Hospital from January to Jane in 2009 by real-time quantitative PCR. Notch1 ICD protein was detected in 85 archived astrocytic tumor samples at different grades using immunohistochemical method.    Results  Mild or low expression of Notch1 ICD mRNA was found in normal cerebral tissues. The expression level of Notch1 ICD mRNA in neoplastic tissues (4.65±3.04) were significantly higher than in normal tissues (1.13±0.11) (P0.01). There was statistical significance of difference of Notch1 ICD mRNA expression between high-grade astrocytic tumors (grade Ⅲ and Ⅳ

n=7) and low-grade tumors (gradeⅡ

n=5) (6.58±2.63 vs 2.49±1.01

P0.01). Immunohistochemical results revealed that obvious upregulation of Notch1 ICD protein was seen in neoplastic tissues

and transformation of protein localization from pure cytoplasmic staining

combined cytoplasmic and nuclear staining

to pure nuclear staining. The expression of Notch1 ICD protein was correlated with histological grade and patient’s survival time. Higher expression of Notch1 ICD protein predicted higher malignant grade and shorter survival time.    Conclusion  Activation of Notch signaling is frequently found in astrocytic tumors. Aberrant expression of Notch1 ICD is correlated with tumor malignant grade and patient’s survival

which implies that Notch1 might be one of useful target molecules for anti-glioma gene therapy.