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

ObjectiveTo assess the insulin-like growth factor-1 receptor (IGF1R) expression in urothelial carcinoma (UC) and its prognostic role in relation to clinicopathologic parameters.MethodsA 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.ResultsWe 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.ConclusionWe 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.