FGF7 Over Expression is an Independent Prognosticator in Patients with Urothelial Carcinoma of the Upper Urinary Tract and Bladder

Abstract

Urothelial carcinoma of the bladder and upper tract is the most common tumor type in the urinary tract but its molecular pathogenesis and survival determinants remain obscure. By data mining a published transcriptomic database of bladder urothelial carcinoma (GSE31684) we identified FGF7 as the most significant gene up-regulated during urothelial carcinoma progression. We then used our well characterized urothelial carcinoma cohort to analyze FGF7 transcript and protein expression, and its clinicopathological significance. We performed real-time reverse transcriptase-polymerase chain reaction assay to determine the FGF7 transcript level in 30 fresh samples each of upper tract and bladder urothelial carcinoma. Immunohistochemistry evaluated by H-score was used to determine FGF7 protein expression in 340 upper tract and 295 bladder urothelial carcinomas. Transcript and protein expression were correlated with clinicopathological features. We further evaluated the prognostic significance of FGF7 protein expression for disease specific and metastasis-free survival. An increased FGF7 transcript level was associated with higher pT stage in upper tract and bladder urothelial carcinoma (p = 0.003 and <0.001, respectively). In the upper tract and bladder carcinoma groups FGF7 protein over expression was also significantly associated with advanced pT status (each p <0.001), lymph node metastasis (p = 0.002 and <0.001), high histological grade (p = 0.019 and <0.001), vascular invasion (each p <0.001), perineural invasion (p = 0.002 and 0.021) and frequent mitoses (p = 0.002 and 0.042, respectively). FGF7 over expression predicted dismal disease specific and metastasis-free survival on univariate and multivariate analysis. Our study shows that FGF7 over expression is associated with advanced clinical features in patients with upper tract and bladder urothelial carcinoma, justifying its potential prognostic value for urothelial carcinoma.