The relationship between serum E2F1 and MMP-9 levels and clinical and pathological characteristics and prognosis in patients with epithelial ovarian cancer

To investigate the association between serum levels of E2F transcription factor 1 (E2F1) and matrix metalloproteinase 9 (MMP-9) in patients with epithelial ovarian cancer (EOC) and their clinical and pathological characteristics and prognosis, with the aim of identifying potential biomarkers for EOC prognosis assessment. A retrospective study was conducted on 80 patients with EOC admitted to our hospital between January 2021 and January 2024. Based on 2-year follow-up outcomes, patients were divided into a survival group (n = 54) and a death group (n = 26). Serum levels of E2F1 and MMP-9 were measured using enzyme-linked immunosorbent assay (ELISA). The associations between biomarker levels and clinicopathological characteristics were analyzed using chi-square tests. Prognostic factors were identified via Cox regression analysis. Kaplan-Meier curves and ROC analyses were performed to evaluate predictive performance. External validation was conducted using the Kaplan-Meier Plotter public database (http://kmplot.com). A nomogram integrating clinicopathological features and biomarkers was constructed and evaluated by calibration curve and decision curve analysis (DCA). Internal validation of the multivariate Cox model was performed using Bootstrap resampling with 1000 iterations. High E2F1 and MMP-9 expression were significantly associated with advanced FIGO stage, poor differentiation, and lymph node metastasis (all P<0.05). Multivariate Cox regression analysis revealed that FIGO stages III–IV, low tumor differentiation, lymph node metastasis, high E2F1 expression, and high MMP-9 expression were independent risk factors for poor prognosis in EOC patients (all P < 0.05). KM curves showed that high E2F1 (HR=8.036, 95%CI:3.018–21.390), high MMP-9 (HR=6.936, 95%CI:3.052–15.760), and combined high expression (HR=16.410, 95%CI:6.763–39.830) were significantly associated with increased mortality risk (all P<0.001). The combined AUC was 0.941, superior to individual markers and CA125 (AUC=0.787, P=0.017 for DeLong test). Public database validation confirmed that high E2F1 (HR=1.25, 95%CI:1.05–1.48, P=0.01) and MMP-9 (HR=1.35, 95%CI:1.14–1.60, P=0.00052) mRNA expression were associated with poorer OS. The nomogram incorporating E2F1, MMP-9, FIGO stage, grade, and lymph node metastasis achieved an AUC of 0.960 (95%CI:0.918–0.991) after Bootstrap internal validation, significantly outperforming FIGO stage alone (AUC=0.793, 95%CI:0.705–0.878), with DCA demonstrating superior net clinical benefit. Serum E2F1 and MMP-9 may serve as independent prognostic biomarkers in EOC. Combined detection appears to significantly improve prognostic prediction, and the nomogram incorporating these biomarkers shows potential to outperform traditional FIGO staging, suggesting a practical tool for risk stratification and personalized management. These findings are exploratory and warrant further validation in prospective cohorts.