BIOMARKERS OF UROTHELIAL DAMAGE IN PATIENTS TREATED BY ADJUVANT INTRAVESICAL THERAPY

Introduction/Aim: Chemotherapy or BCG given intravesically to prevent recurrence after transurethral resection (TUR) of non-muscle invasive bladder cancer (NMI-BC) cause frequent, sometime severe, local toxicity. As a consequence, many patients do not complete the planned treatment (1). A major challenge for the urologists is to identify an early biomarker of urothelial damage to recognize and prevent local toxicity improving patient’s compliance. The purpose of our research was to investigate the relation between urothelial injury by intravesical treatment and the expression of potential biomarkers in urine and/or in barbotage solution. The urinary HB-EGF expression in interstitial cystitis has been analyzed by a few studies (2, 3). As a preliminary step, the variations of Fibronectin (FN), Epidermal Growth Factor- Receptor (EGF-R) and Heparin-binding Epidermal Growth Factor-like Growth Factor (HB-EGF) during intravesical therapy and after the administration of a solution with the potential role of urothelial repairing (hyaluronic acid and chondroitin sulphate) were investigated. Patients and Methods: the toxicity of intravesical therapy with mitomycin, epirubicin or BCG was classified in 3 grades (absent, moderate, severe). Urine and bladder washing solution during intravesical therapy in 55 patients after NMI-BC TUR and in 10 healthy controls for a total of 200 samples were collected. Total cellular RNA was isolated from the cell pellet using miRNeasy Mini Kit (Qiagen®). FN and EGF-R gene expression by Real Time quantitative PCR were analyzed. The expression of HB-EGF was measured in urine samples by ELISA (Abcam®). Results: In barbotage samples the FN gene expression and the EGF-R levels in our patients were respectively increased a median of 4.7 fold and decreased of 0.9 fold compared to controls. Before intravesical therapy and in absence of local toxicity, gene expression increased 1.9 fold for FN and 1.1 fold for EGF-R. In contrast, in patients with local toxicity due to intravesical therapy, the FN gene expression levels increased to a median of 5.82 fold, while EGF-R remained unchanged. The administration of hyaluronic acid and chondroitin sulphate solution decreased the mean FN gene expression from 3 to 0.6 fold, with concomitant symptomatic relief. HB-EGF protein median urine levels were 25.7 pg/ml in 13 patients before intravesical therapy and 18.9 pg/ml in 5 healthy controls. No significant variations in relation to the local toxicity. During therapy median HB-EGF protein levels in urine varied from 21.6 pg/ml in absence of toxicity to 25.7 pg/ml in case of severe toxicity to 18.5 pg/ml after hyaluronic acid and chondroitin sulphate solution. Preliminarily, the observed variations of HB-EGF, increasing no more than 1.2 fold compared to healthy controls, do not seem possible marker of urothelial damage. Discussion and Conclusion: EGF-R gene and HBEGF expressions do not seem to vary significantly in relation to local toxicity due to intravesical therapy. FN gene is overexpressed in presence of urothelial damage significantly reduced by intravesical hyaluronic acid and chondroitin sulphate solution administration, according with symptoms relief.