Epidermal growth factor expression as a predictor of chemotherapeutic resistance in muscle-invasive bladder cancer

BACKGROUND: Epidermal growth factor receptor (EGFR) overexpression is believed to be associated with bladder cancer (BC) progression and poor clinical outcomes. In vivo studies have linked EGFR subcellular trafficking and chemo-resistance to cisplatin-based chemotherapies. This has not been studied in the clinical adjuvant setting. We aimed to investigate the prognostic significance of EGFR expression in patients receiving cisplatin-based adjuvant chemotherapy following radical cystectomy for advanced BC. METHODS: The database from the Urology and Nephrology Center at Mansoura University was reviewed. BC patients who were treated with radical cystectomy and adjuvant chemotherapy for adverse pathological features or node positive disease were identified. Patients who underwent palliative cystectomy, had histological diagnoses other than pure urothelial carcinoma, or received adjuvant radiotherapy were excluded from the study. Immunohistochemical staining for EGFR expression was performed on archived bladder specimens. The following in vitro functional analyses were performed to study the relationship of EGFR expression and chemoresponse. RESULTS: The study included 58 patients, among which the mean age was 57 years old. Majority of patients had node positive disease (n = 53, 91%). Mean follow up was 26.61 months. EGFR was overexpressed in 25 cystectomy specimens (43%). Kaplan-Meier analysis revealed that EGFR over-expression significantly correlated with disease recurrence (p = 0.021). Cox proportional hazard modeling identified EGFR overexpression as an independent predictor for disease recurrence (p = 0.04). Furthermore, in vitro experiments demonstrated that inhibition of EGFR may sensitize cellular responses to cisplatin. CONCLUSIONS: Our findings suggest that EGFR overexpression is associated with disease recurrence following adjuvant chemotherapy for advanced BC. This may aid in patient prognostication and selection prior to chemotherapeutic treatment for BC.