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.