Objective To study the expression and the clinical significance of Wnt signal pathway regulation factor Pygo2 in human renal cell carcinoma.Methods Using RFQ-PCR and immunohistochemical SP methods to detect Pygo2 mRNA and protein expression in 42 cases renal clear cell carcinoma and their own normal kidney tissue specimens.All specimens had a definite diagnosis by pathologic.All were renal clear cell carcinoma.The tumor diameter was 1.2-15.5 cm.The average was 7.2 cm.Among all patients,there were 7 cases with diameter ＜ 4.0 cm,9 cases 4.0-7.0 cm,26 cases ＞ 7.0 cm.Fuhrman classification:grade Ⅰ 6 cases,grade Ⅱ 17 cases,grade Ⅲ 17 cases,grade Ⅳ 2 cases.AJCC TNM stages:stage Ⅰ 16 cases,stage Ⅱ 7 cases,stage Ⅲ 7 cases,stage Ⅳ 12 cases.Statistics was done to analyze the expression difference of pygo2 between normal kidney and renal cell carcinoma,and among renal cell carcinoma within each group.Results There was higher expression of Pygo2 in renal cell carcinoma,and in the adjacent lower expression.The pygo2 mRNA expression were 2.88 ± 1.26 and 1.00 ± 0.00 in respective specimens (P ＜ 0.0001).The pygo2 protein expression were 45.53 + 24.54 and 11.02 + 1.39 in respective specimens (P ＜ 0.0001).Pygo2 expression in grading and staging were statistically significant (P ＜0.0001),but in gender,age was not statistically significant (P ＞ 0.05).Conclusions High expression of Pygo2 was found in Fuhrman high grade,high clinical staging,lympho-metastasized renal clear cell carcinoma.Pygo2 might play an important role in the occurrence and development process in renal clear cell carcinoma.