Significance of IGFBP-5 expression in urinary bladder urothelial carcinoma

IGFBP5 is one of the recently studied biomarkers in bladder carcinoma, and its exact mechanisms in cancer progression are still unclear. This study aims to analyze the level of IGFBP5 expression in relation to the different clinicopathological variables of urinary bladder urothelial carcinoma. This immunohistochemical study was performed on tissue microarray of urothelial carcinoma cases. A semiquantitative score for IGFBP5 expression was used, and the results of staining were correlated with patient’s characteristics and tumor parameters. Most urothelial carcinoma cases were positive for IGFBP5 (97.5%). 67.5% of the cases showed high level of IGFBP5 expression, and the proportion was similar between low- and high-grade tumors. All normal tissue samples showed low expression level. The tumor grade was significantly associated with IGFBP5 expression level (Pearson chi-square p = 0.007). No significance was found upon performing the trend test, while Fisher’s exact test showed a significant grade association (Fisher’s exact p = 0.013). Higher expression of IGFBP5 was significantly associated with decreased overall survival upon performing univariate survival analysis on public transcriptomic (TCGA-BLCA) data (log-rank p = 0.037), while there was no independent association on multivariate analysis. The present study evaluated an independent Asian cohort that showed higher levels of IGFBP5 expression in urothelial carcinomas than in normal tissue samples. The clustering of negative cases among the high-grade tumors points to a context-dependent IGFBP role in urothelial carcinoma.