β-catenin is a kind of cytoplasmic protein involved in cell adhesion and signal transduction. This study investigated its expression in various subtypes of renal cell carcinomas (RCCs) using an immunohistochemical staining method. β-catenin expression was assessed from staining frequency and staining score. Staining score was performed by evaluating both staining percentage and intensity. All subtypes of RCCs reacted positively with β-catenin. However, the positive frequency and staining score in papillary and chromophobe RCCs were significantly higher than those in conventional RCCs (p<0.05). In addition, in conventional RCCs, the positive frequency and staining score of β-catenin showed a significant difference between nuclear grades I/II and grade III (p<0.05). Therefore, it may indicate that β-catenin can serve as a complementary tool to distinguish conventional RCCs from chromophobe RCCs. In conventional RCCs with low nuclear grades, β-catenin expression is generally down-regulated, while it appears to be preserved in those with high nuclear grades.

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