Immunohistochemical Expression of CD24 and Its Correlation with Clinicopathological Features in Malignant Surface Epithelial Tumors of the Ovary

Background Surface epithelial ovarian cancer (EOC) is the deadliest gynecological malignancy, mainly due to late-stage diagnosis and therapeutic resistance. Intratumoral heterogeneity, driven by cancer stem cells (CSCs), contributes to metastasis, recurrence, and therapy resistance. Cluster of Differentiation 24 (CD24) has emerged as a promising biomarker linked to tumor progression, metastasis, and immune evasion, but further research is needed to understand its role in ovarian cancer progression and patient outcomes. Aim This study investigates the immunohistochemical expression of CD24 in malignant surface epithelial ovarian tumors and its correlation with clinicopathological parameters and patient outcomes. Methods We performed a retrospective cohort analysis involving 117 formalin-fixed, paraffin-embedded (FFPE) samples of malignant ovarian surface epithelial tumors, retrieved from the archives of the Surgical Pathology Laboratory at our University oncology center in the period between 2018 and 2021. Patients underwent surgical resection, with follow-up data collected until 2024. Immunohistochemical (IHC) staining for CD24 was performed, and expression levels were assessed based on staining percentage and intensity. The correlation between CD24 expression and clinicopathological factors, disease-free survival (DFS), and overall survival (OS) was analyzed using appropriate statistical methods, including Kaplan-Meier survival analysis and Cox regression. Results CD24 expression was observed in 61.5% of cases, with varying expression levels: low (17.9%), moderate (23.1%), and high (20.5%). High CD24 expression was predominantly observed in HGSC (p = 0.02) and was significantly associated with advanced FIGO stage (p = 0.001), high tumor grade (p = 0.001), lymph node involvement (p = 0.001), positive peritoneal cytology (p = 0.001), and distant metastases (p = 0.085). Survival analysis revealed that patients with high CD24 expression exhibited significantly shorter DFS (p = 0.001) and a non-significant trend toward reduced OS (p = 0.499), compared to those with lower or absent expression. Cox regression identified CD24 as an independent predictor of poor prognosis, alongside age, tumor stage, and lymph node involvement. Conclusion CD24 overexpression in surface epithelial ovarian cancer is strongly correlated with aggressive tumor behavior, advanced stage, and poor survival outcomes. These findings support the incorporation of CD24 expression into risk stratification models and highlight the potential of CD24-targeted therapies to improve ovarian cancer outcomes.