IGFBP-5 overexpression as a poor prognostic factor in patients with urothelial carcinomas of upper urinary tracts and urinary bladder

Background Urothelial carcinoma (UC) is prevalent worldwide. Dysregulation of cell growth is a critical event of tumorigenesis and has not been assessed systemically in UC. We thus assessed the published transcriptome of urinary bladder urothelial carcinoma (UBUC) and identified insulin-like growth factor-binding protein-5 (IGFBP-5) as the most significantly upregulated gene associated with the regulation of cell growth. Moreover, validated by using public domain data set, IGFBP-5 expression also significantly predicted worse outcome. IGFBP-5 is one of the binding proteins that regulate insulin-like growth factors (IGFs) and its significance has not been comprehensively evaluated in UCs. Methods Using immunohistochemistry, we evaluated the IGFBP-5 expression status and its associations with clinicopathological features and survival in 340 cases of upper urinary tract urothelial carcinoma (UTUC) and 295 cases of UBUC. Western blot analysis was used to evaluate IGFBP-5 protein expression in human urothelial cell (HUC) lines. Results IGFBP-5 overexpression was significantly associated with advanced pT stage (p Conclusions IGFBP-5 plays an important role in tumour progression in UC. Its overexpression is associated with advanced tumour stage and conferred poorer clinical outcome.