Immuno-reactivity of Engrailed (EN)-2 in Epithelial Ovarian Neoplasms

Background: Ovarian neoplasm refers to any tumor that originates primarily in the ovary. Epithelial ovarian neoplasms are the most common type of ovarian tumor and are classified based on their histogenetic and immunophenotypic features. However, treatment modalities based on this classification have shown limited improvements in patient outcomes. Engrailed (EN)-2 was first identified as a regulator of embryonic neural development and later found to be expressed in various non-neural epithelial tumors. Aim: This study aimed to investigate the potential role of the EN-2 gene in epithelial ovarian tumors by comparing the expression of EN-2 protein in functional ovarian lesions and ovarian epithelial neoplasms. It also aimed to correlate EN-2 expression levels with factors such as patient age, tumor size, and carcinoma grade. Methods: Archived formalin-fixed, paraffin-embedded ovarian tissue blocks from 47 women who underwent oophorectomies for various gynecological indications were examined. Two tissue sections were obtained from each block: one was stained with Hematoxylin and Eosin, and the other was immunohistochemically stained with an anti-human EN-2 antibody. Results: EN-2 was overexpressed in malignant ovarian neoplasms compared to benign tumors and non-neoplastic lesions (p < 0.0001). The expression of EN-2 was significantly associated with older patient age (p=0.003) and larger tumor size (p < 0.0001). Conclusion: EN-2 is aberrantly expressed in epithelial ovarian neoplasms, with increased expression observed in malignant tumors and larger tumor sizes, suggesting its potential as a biomarker for tumor progression in ovarian carcinoma.