Erythropoietin receptor expression in bladder cancer

Abstract

4584 Background: Several groups have implicated erythropoietin receptor (EPOR) expression in cancer progression, angiogenesis and cell survival. No clinical data about its implication in bladder cancer has been reported. So, our main objective was to determine the expression of EPOR in bladder cancer specimens after radical cystectomy and its potential relation with disease free survival (DFS) and overall survival (OS). Methods: Patients diagnosed with invasive grade 3 bladder cancer were included after radical cystectomy. None of them had node involvement after pathological examination. Data about pathological stage (pT), DFS and OS were recorded. EPOR expression was analyzed by immunohistochemistry in paraffin embedded samples. An expert uro-pathologist ensured enough tumoral proportion in every sample. EPOR antibody was targeted against the extracellular domain of this receptor (Santa Cruz, CA). Positive immunostaining was defined when more than 80% tumoral cells showed a cytoplasmatic staining pattern. Results: Of the 75 consecutive patients included (pT1 = 11; pT2 = 21; pT3 = 21; pT4 = 22), 40 (53.3%; 95% CI 42.61- 64.23) had EPOR expression. No correlation was observed between EPOR expression and pathological stage. Median DFS was 10 months for patients with EPOR expression and was not reached for individuals without receptor expression after 22 months of follow-up (logrank test p < 0.0001). Furthermore, univariate analysis showed that pathological stage had no statistical influence. Finally, multivariate analysis showed only EPOR expression as predictor for DFS and OS (p = 0.0009). Conclusions: EPOR expression is a strong prognostic factor after radical cystectomy in grade 3 bladder cancer patients without node involvement. No significant financial relationships to disclose.