Epigenetic mechanisms and clinical translation in ovarian cancer: from molecular pathways to precision therapy

Ovarian cancer remains one of the deadliest gynecological malignancies, mainly due to its late diagnosis, biological heterogeneity, and frequent development of chemoresistance. Recent evidence indicates that epigenetic dysregulation including aberrant DNA methylation, histone modifications, chromatin remodeling, and non-coding RNA networks plays an important role in the initiation, progression, and therapeutic response of ovarian cancer. Unlike genetic alterations, epigenetic modifications are reversible, making them attractive targets for drug development and precision oncology. In this review, we provide a detailed overview of the epigenetic mechanisms that control ovarian cancer biology, with specific focus on their role in drug resistance and disease recurrence. We discuss the role of epigenetic plasticity in enabling transition of tumor cells into drug tolerant, stem like phenotypes, leading to minimal residual disease and eventual relapse without permanent genetic changes. Attention is given to the influence of DNA methyltransferases, histone deacetylases, enhancer of zeste homolog 2, and chromatin remodeling complexes in the maintenance of adaptive resistance programs. We also discuss the evolving paradigm of epigenetic regulation, immune modulation and viral mimicry and provide the rationale for combining epigenetic therapies with immunotherapy and poly(ADP-ribose) polymerase inhibition. The article also reviews the results of recent clinical trials and evaluate the most recent advances in biomarker development, such as circulating DNA methylation signatures, microRNAs, and artificial intelligence-based liquid biopsy platforms. Finally, we discussed the potential implications of applying epigenetic profiling in the clinic for improved patient stratification and the potential for real-time monitoring of chemoresistance. These progresses make epigenetic regulation a promising strategy to overcome chemoresistance and improve personalized medicine of ovarian cancer.