Snail expression is an independent predictor of tumor recurrence in superficial bladder cancers

Abstract

Background Epithelial-mesenchymal transition (EMT) is known to play an important role in the development of tumor invasion and progression in tumors of epithelial origin. Objectives Our aim was to investigate the role of Snail transcription repressor family members in human bladder pathogenesis. Material and methods We evaluated levels of Snail and Slug in 87 patients who received transurethral resection of a transitional cell carcinoma at our institution during the period from June 1999 until November 2003. Immunohistochemistry was performed on tissue microarrays, and expression correlated with pathological variables and clinical outcomes. Degree and intensity of Snail and Slug staining was quantified by immunohistochemistry. Results There was no apparent enrichment in strong vs. weak staining for either Snail (43.7% vs. 56.3%) or Slug (46% vs. 54%) in the superficial bladder tumors. Univariate analysis determined that tumor focality and Snail expression were significantly associated with tumor recurrence ( P < 0.05). Only for tumor focality did such a relationship exist when assessing tumor progression. Multivariate analysis using the Cox's proportional hazards model revealed similar results to that of the univariate analysis. Snail expression ( P = 0.038) and tumor focality ( P = 0.011) were independent and significant prognostic factors for tumor recurrence in all patients. However, only tumor focality was an independent predictor of tumor progression ( P = 0.034). Conclusions High expression of Snail in superficial bladder tumors is a strong predictor of tumor recurrence enhancing risk stratification and prognostication.