Clinical Significance of Heme Oxygenase-1 Expression in Non-Muscle-Invasive Bladder Cancer

Introduction: In several malignant diseases, elevated heme oxygenase-1 (HO-1) is associated with progression or resistance to chemotherapy. We evaluated the clinical significance of HO-1 expression in non-muscle-invasive bladder cancer. Patients and Methods: We examined 109 patients with non-muscle-invasive bladder cancer. The immunoexpression of HO-1, p53, and Ki-67 was analyzed using paraffin-embedded tissue from transurethral resection in comparison with the clinicopathological variables. Results: Positive expression of HO-1 was found in 66 of 109 tumors (61%), and the positivity of HO-1 correlated significantly with high tumor grade and the altered expression patterns of p53 and Ki-67. In our analysis of 16 cases treated by intravesical administration of anthracyclines, the positive expression of HO-1 correlated with poor disease-free survival (p = 0.015). In in vitro experiments using urothelial cancer cell lines, HO-1 upregulation was observed by exposure to doxorubicin. Moreover, siRNA-mediated suppression of HO-1 upregulation sensitized the urothelial cancer cells to doxorubicin. Conclusions: Our findings suggested that resistance against anthracyclines correlated with HO-1 and expression analysis of HO-1 may be a useful predictive marker for intravesical administration of anthracyclines. Copyright (C) 2010 S. Karger AG, Basel