Combined Assessment of EZH2 and EGFR as Potential Diagnostic Biomarkers for Epithelial Ovarian Tumors: Bioinformatics Analysis and Clinical Validation.

PURPOSE: This study was to investigate the expression and clinical significance of Enhancer of Zeste Homolog 2 (EZH2) and Epidermal Growth Factor Receptor (EGFR) in epithelial ovarian cancer (EOC). METHODS: EZH2 and EGFR in EOC were analysed by bioinformatics. Samples from 55 patients with epithelial ovarian tumors (22 malignant, 14 borderline, and 19 benign) and 10 normal ovarian tissue were collected, EZH2 and EGFR expression levels were measured by immunohistochemistry (IHC) and Enzyme-Linked Immunosorbent Assay (ELISA). RESULTS: Public-database analyses indicated increased EZH2 but decreased EGFR expression in ovarian serous cystadenocarcinoma relative to normal ovarian tissue (P<0.05). In the clinical cohort, tissue and serum measurements of EZH2 and EGFR were progressively higher across the normal, benign, borderline, and malignant groups (AUC tissue EZH2+ tissue EGFR (0.944) >AUC serum EZH2+ serum EGFR (0.942) =AUC tissue EZH2 (0.942) >AUC serum EZH2 (0.863) >AUC tissue EGFR (0.839) >AUC serum EGFR (0.818), ROC analyses distinguish malignant versus borderline EOC. For distinguishing malignant tumors from benign tumors and normal controls, the apparent AUCs of the combined tissue and serum models were 0.944 and 0.942, respectively; the corresponding optimism-corrected AUCs were both 0.932. For distinguishing malignant from borderline tumors, the apparent and optimism-corrected AUCs were 0.903 and 0.885, respectively, for the tissue model and 0.666 and 0.576, respectively, for the serum model. CONCLUSION: EZH2 and EGFR are highly expressed and have diagnostic value for EOC, combined detection offered superior diagnostic performance.