Insulin-like Growth Factor-1 Receptor Overexpression Is Associated With Outcome in Invasive Urothelial Carcinoma of Urinary Bladder: A Retrospective Study of Patients Treated Using Radical Cystectomy

OBJECTIVE To assess the insulin-like growth factor-1 receptor (IGF1R) expression in urothelial carcinoma (UC) and its prognostic role in relation to clinicopathologic parameters. METHODS A total of 100 cases of invasive UC were evaluated using tissue microarrays. Membranous IGF1R staining was evaluated using immunohistochemistry. A scoring method analogous to that of HER2 expression in breast carcinoma was used, and the highest score was assigned in each tumor. IGF1R was considered overexpressed in cases with score >= 1. RESULTS We found IGF1R overexpression in 62% of invasive UC. IGF1R overexpression was associated with race (P = .04) and pT category (P = .03). Median follow-up was 29 months (range, 0.5-212). Progression rate was 60%, and overall mortality and cancer-specific mortality rates were 69% and 51%, respectively. In invasive UC, IGF1R overexpression was significantly associated with overall mortality and cancer-specific mortality (Mantel Cox P = .0002 and P = .006, respectively). IGF1R overexpression was associated with increased hazard ratios (HRs) for overall mortality (HR = 2.63, P = .001) and cancer-specific mortality (HR = 2.45, P = .01), independently and after adjusting for clinicopathologic features and treatment modalities. CONCLUSION We found IGF1R overexpression in 62% of bladder UC. More importantly, IGF1R overexpression was a significant predictor of overall mortality and cancer-specific mortality, suggesting its potential role as a prognosticator in UC of bladder. (C) 2014 Elsevier Inc.