Adhesion molecules alpha, beta and gamma-catenin as prognostic factors of tumour progression in upper urinary tract urothelial tumours: the role of AKT-P/GSK-3beta/beta-catenin pathway.

OBJECTIVES To evaluate alpha, beta and gamma-catenin expression in upper urinary tract urothelial tumours (UUTC) and determine their value as prognostic factors; to investigate the correlation between the catenin complex and the AKT pathway. PATIENTS AND METHODS We retrospectively analysed 114 consecutive patients treated at our institution from 1990 to 2004; the mean follow-up was 54 months. Tumour samples were available from 70 patients, and included in tissue microarrays for immunohistochemical analysis. The antibodies used were anti-alpha, -beta and gamma-catenin, and antiphospho-AKT. The prognostic value of the expression of these molecules was analysed using tumour progression and cancer-specific survival as end-points. RESULTS Of the 114 patients, 27% developed tumour progression; the cancer-specific and overall survival were 77% and 60.6%, respectively. Abnormal alpha, beta and gamma-catenin expression was found in 44 (63%), 22 (31%) and 28 (41%) patients, respectively; the abnormal catenin expression patterns correlated with each other. Positive cytoplasm phospho-AKT expression was found in 27 (39%) patients. Three of them were found to have cytoplasmic beta-catenin accumulation and none of them nuclear expression. beta-catenin expression was the only one that was an independent marker of tumour progression, with a hazard ratio (95% confidence interval) of 3.1(1.2-8.6), together with grade (7.1, 1.2-55.8) and stage (4.6, 2.1-10). In the cancer-specific survival analysis, again beta-catenin was an independent prognostic factor (3.4, 1-11.5) together with stage (4.6, 2.2-9.8). CONCLUSIONS The loss of the normal membrane beta-catenin expression constitutes an independent factor of tumour progression and cancer-specific survival. Our data suggest that the AKT/GSK3beta/beta-catenin signalling pathway is not activated in the UUTC carcinogenesis.