FGFR3, a marker suggestive of favorable prognosis in urothelial carcinoma

Abstract

The detection of fibroblast growth factor receptor 3 (FGFR3) mutations in noninvasive bladder cancer mostly and a finding of FGFR3 overexpression in many invasive bladder cancers (BC) has created hope that targeted therapy against FGFR3 may have a major role in the treatment of BC. We aimed to evaluate immunohistochemically the expression of FGFR3 in urothelial carcinoma of the urinary bladder and correlate the results with various clinicopathologic variables to show the possible prognostic value of this marker. This study included 100 archived paraffin blocks of variable grades and stages of urothelial carcinoma. All cases were immunohistochemically stained with anti-FGFR3 antibody. FGFR3 immunostaining was detected in 88% (88/100) of urothelial carcinoma cases. A significant correlation was detected between FGFR3 expressions with the grade and depth of tumor invasion as 34% of low-grade cases (P = 0.002) and 26% of pTa-stage tumors (P = 0.02) showed high level of FGFR3 expression. Moreover, FGFR3 was significantly highly expressed in 34% of non-muscle-invasive tumors (P = 0.007), 34% of tumors with papillary growth pattern (P = 0.017), and lower-stage tumors (P = 0.00). In conclusion, high expression of FGFR3 in urothelial carcinomas with statistically significant relationships regarding its expression levels with parameters of favorable prognosis like low grade and pTa stage, presence of papillary architecture, and lower-stage urothelial carcinomas raised the probability that FGFR3 expression may have a role in early development of urothelial neoplasia. Further studies are required to investigate the applicability of FGFR3-targeted agents as an additional treatment regimen in patients with FGFR3 overexpression.