Abstract: Expression and Clinical Significance of Pygo2 in Glioma Cells and TissueHaidongWANG1, Yuying CHEN2, ZhanxiangWANG1, Xiyao LIU1, Guowei TAN1, Shanghang SHEN1Correspondence to: ZhanxiangWANG, E-mail: wangzx@xmbrain.com1Department of Neurosurgery, First Hospital Affiliated to Xiamen University, Xiamen 361003, China2College of Bio-information, Chongqing University of Posts and Telecommunications, Chongqing 400065, ChinaThis work was supported by the Natural Science Foundation of Fujian (No. 2009D002), Science and Technology Bureau Foundation ofXiamen City (No. 3502z20089001), China Postdoctoral Science Foundation (No. 20080440728), and the Science and Technology Proj-ect from Chongqing Municipal Education Committee (No. KJ100504)Abstract Objective: To detect mRNA and protein expression of Pygopus2 (Pygo2) in glioma tissues and cells, and to study theclinical significance. Methods: The mRNA expression of Pygo2 in 5 glioma cell lines was quantified by reverse transcription-poly-merase chain reaction ( RT-PCR ), and mRNA expression of Pygo2 in 67 Ⅱ-Ⅳ glioma tissue samples was quantified by Real-time Re-verse Transcription ( RT )-PCR analysis, and protein expression of Pygo2 was evaluated in 80 of glioma tissue samples by SP Immuno-histochemistry ( IHC ) analysis. Results: Pygo2 mRNA was expressed in all of five cell lines with the highest expression in U251 cellsand the lowest expression in C6 cells. Pygo2 mRNA expression was very low in normal brain specimens, and the mRNA expression ofPygo2 was significantly increased in Ⅱ-Ⅳ glioma grade compared with that in normal brain samples. Moreover, the increased Pygo2mRNA expression was correlated with the high grade of human glioma ( P < 0.05 ). Pygo2 protein was locatated in the nucleus of glio-ma epithelial cells. Negative immunostaining for Pygo2 protein was observed primarily in normal brain tissue sections, and positive im-munostaining for Pygo2 protein was detected in 52/80 ( 65.0 % ) glioma samples, with significant difference between normal brain tis-sue and glioma samples ( P < 0.01 ). Weak and strong immunostaining was shown in low malignant ( WHO Ⅱ ) and highly malignant (WHO Ⅳ ) brain gliomas respectively. The frequency of positive expression for individual pathological stages was 5/13 ( 38.5 % ) forstageⅠ, 12/26 ( 46.2 % ) for stage Ⅱ, 15/19 ( 7 8.9 % ) for stage Ⅲ, and 20/22 ( 90.9% ) for stage Ⅳ. Pygo2 protein expression wassignificantly correlated with tumor grade ( P < 0.01 ). In addition, Pygo2 protein expression was not related to patients' gender or age (P > 0.05 ). Conclusion: Pygo2 protein expression was not tound in normal brain tissue. Pygo2 was highly expressed in glioma tissue,and was correlated with high tumor grade, indicating that Pygo2 plays an important role in carcinogenesis and progression of glioma.