The complementary role of beta-catenin in diagnosing various subtypes of renal cell carcinomas and its up-regulation in conventional renal cell carcinomas with high nuclear grades

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