Snail immunohistochemical overexpression correlates to recurrence risk in non-muscle invasive bladder cancer: results from a longitudinal cohort study.

The current WHO/ISUP classification and grading system subdivides urothelial tumours into prognostically distinct categories. Understanding the molecular pathways involved in bladder cancer development can improve patient stratification and management. This study aims to investigate the relationship between Snail, Slug and E-cadherin expressions and clinico-pathological features of non-muscle invasive bladder carcinoma (NMIBC). All patients attending the same urological centre from January to May 2002, who were pathologically diagnosed with NMIBC, were enrolled in this longitudinal cohort study. E-cadherin, Snail and Slug protein expressions were assessed by immunohistochemical analysis and compared with follow-up data. The main outcome measures were recurrence and progression rates. The cohort under investigation included 43 patients (38 men and 5 women, mean age 67.7 ± 10.6 years). High-grade (HG) carcinomas were 20/43, with 10 invasive cases (pT1). Low-grade (LG) carcinomas were 23/43, with no invasive cases (pTa). Among the eight HGpTa cases with recurrence, strong Snail expression was detected in six (75%). Out of the 17 LGpTa patients who experienced recurrence, 12 (70.6%) showed strong positivity for Snail. Among the 10 HGpT1 cases, recurrence was observed in 4, of which, 3 (75%) stained intensely for Snail. The Kaplan-Meier curves showed significantly different recurrence rates for patients with strong or weak Snail reactivity (p = 0.027). E-cadherin and Slug expression did not correlate with any of the parameters considered. On multivariate analysis, Snail expression was recognised as an independent prognostic factor for tumour recurrence (p = 0.003). In our study population, Snail immunohistochemical overexpression proved to be related to tumour recurrence in patients affected by NMIBC.