The expression and prognostic value of alpha-, beta- and gamma-catenins in renal cell carcinoma.

Background: Catenins have prognostic value in several human tumours. The aim of the study was to analyse the prognostic value of catenin expression in a prospectively followed series of renal cell carcinoma. Patients and Methods: One hundred and twenty-four renal cell carcinomas were prospectively followed-up for a mean of 3.5 years and the survival data of patients were related to standard prognostic factors and to the results of alpha-, beta- and gamma-catenin immunohistochemistry. The data of catenin immunohistochemistry were also related to the clinical and histopathological characteristics of the tumours. Results: Low cytoplasmic alpha-catenin expression was related to lymphatic tumour growth (p=0.02) and to tumour necrosis (p=0.02). The weak expression intensity of beta-catenin on cell membranes was related to venous growth inside the tumour (p=0.02), extratumoural venous growth (p=0.03) and to perineural growth (p<0.001). Nuclear gamma-catenin expression was strongly associated with clear cell type (p=0.0001) and high WHO grade (p=0.038). Short recurrence-free survival was predicted by weak membranous alpha- catenin (p=0.015) and beta-catenin (p=0.006) expression intensity, while their cytoplasmic expression was of lower significance (p=0.07 and 0.045, respectively). All the conventional prognostic factors predicted short recurrence-free survival: Fuhrman classification (p=0.02), WHO grade (p=0.026), perineural growth (p=0.013), venous invasion (p=0.0024), tumour size (p=0.004) and T-category (p=0.0001). Independent predictors of short recurrence-free survival were weak membranous expression intensity of beta-catenin (RR=0.15, p=0.004), high T-category (RR=2.70, p=0.001) and high WHO grade (RR=2.24, p=0.025). Conclusion: The results show that immunohistochemical analysis of beta-catenin expression may be used as an indicator of aggressiveness in renal cell carcinoma.