FGFR3 mRNA expression in urothelial bladder cancer: Associations with tumor phenotype without prognostic impact.

INTRODUCTION

FGFR3 (fibroblast growth factor receptor 3) is frequently altered in urothelial carcinoma and has been associated with less aggressive disease, but its prognostic relevance remains uncertain. We evaluated tumor FGFR3 mRNA expression levels in relation to clinicopathological phenotype and outcomes in bladder cancer.

MATERIAL AND

METHODS

Fresh-frozen tumor tissue from 80 urothelial carcinomas (54 non-muscle-invasive, 26 muscle-invasive) was used for RNA extraction and quantitative PCR. FGFR3 expression levels were normalized to pooled controls and log10-transformed. Associations with invasiveness, grade, and survival were assessed using logistic and Cox regression, with discrimination quantified by the area under the curve (AUC) and calibration by the Brier score.

RESULTS

Higher FGFR3 expression was independently associated with non-muscle-invasive disease (OR 6.35, 95% CI: 2.14-18.83; p <0.001; AUC 0.74; Brier 0.180) and low grade (OR 5.99, 1.78-20.13; p = 0.004; AUC 0.74; Brier 0.189). FGFR3 was not associated with overall survival (HR 0.52, 95% CI: 0.25-1.06; p = 0.072). In the NMIBC subset, FGFR3 was not associated with recurrence-free survival (HR 1.09, 0.37-3.20; p = 0.880). Age (HR 1.03, 0.98-1.09; p = 0.191) and grade (HR 2.16, 0.78-5.94; p = 0.137) were also non-significant.

CONCLUSIONS

Tumor FGFR3 mRNA expression was strongly associated with a less aggressive phenotype but showed no independent prognostic value for survival in this cohort. FGFR3 may support phenotypic assessment at diagnosis, while its prognostic role warrants validation in larger studies.