Epigenetics and Cancer: Mechanisms, Therapeutic Targets, and Clinical Advances

Epigenetic dysregulation — encompassing aberrant DNA methylation, histone modification, chromatin remodeling, and non-coding RNA expression — is a hallmark of virtually all human cancers and a major driver of oncogenesis, tumor heterogeneity, and drug resistance. This chapter reviews the mechanistic basis of epigenetic alterations in cancer, examines the clinical development of epigenetic therapies including DNMT inhibitors, HDAC inhibitors, EZH2 inhibitors, and BET bromodomain inhibitors, and discusses emerging combination strategies that harness epigenetic reprogramming to potentiate immunotherapy and targeted treatment.