Evaluation of tissue and urinary survivin expression in non-muscle-invasive bladder cancer

IntroductionApproximately 70% of bladder cancers are non-muscle-invasive (NMIBC), and respond well to endoscopic transurethral resection. However, 70% of these patients experience tumor recurrence. As the tendency for local recurrence and/or progression extends over the lifetime, patients with superficial bladder cancer must undergo life-long surveillance. Combination of cystoscopy and urine cytology is considered the “gold standard” for this surveillance. However, they suffer from drawbacks where cystoscopy is an invasive procedure and urine cytology shows limited ability to detect low grade bladder tumors. Therefore, new non-invasive tests with high sensitivity and specificity that are easy to perform are needed not only for initial diagnosis but also in surveillance for recurrent tumors.ObjectiveTo investigate the magnitude investigate the magnitude of survivin expression in non-muscle-invasive bladder cancer and its possible value as a non invasive diagnostic tool.Patients and methodsFrom March 2010 to October 2010, 68 patients with known history of NMIBC who were scheduled for follow-up cystoscopy in the department of Urology, Alexandria University were included in this study prospectively. All patients underwent cystoscopy under general anaesthesia, and those who were found to have a definite or suspicious lesion(s) in the bladder underwent complete TURBT. Survivin expression was determined in urine and in bladder cancer tissue both by Western blotting and by ELISA.ResultsThe study included 68 patients. Tumor recurrence was detected in 38 patients, of whom, 24 had low grade recurrence. The urinary concentration of survivin was significantly higher in the recurrence group by both detection methods (U = 141, P = 0.018 and χ2 = 10.46, P = 0.001 for ELISA and WB respectively). Survivin by ELISA showed higher sensitivity and specificity (84.4% and 100%) than that by WB (55.3% and 93.3%). In tumor tissue, by both methods, survivin was detected in higher levels than in urine but there was no significant correlation between urinary and tissue levels neither in the whole recurrence group nor in the low grade subgroup.ConclusionUrinary survivin is a useful marker for non-invasive detection of non-muscle-invasive bladder cancer recurrence. Its detection is better using ELISA technique than WB and there is no correlation between its expression in tissue and urine.