The disruption of the epigenetic patterns and its impact on gene expression is recognized as a critical factor in the initiation and progression of cancer. Altered patterns of DNA methylation, histone modifications, and non-coding RNA expression are distinctive features of tumorigenesis. These dynamic shifts in the epigenetic landscape during oncogenic transformation are intricately linked to tumor heterogeneity, the sustained capacity for self-renewal, and the ability to undergo multi-lineage differentiation. The abnormal reprogramming of cancer stem cells presents a formidable challenge in cancer treatment and drug resistance. However, the reversible nature of epigenetic modifications holds significant potential for developing novel cancer treatments through the targeted inhibition of epigenetic modifiers. Utilizing this approach as a standalone therapy or combined with other anticancer treatments has yielded promising outcomes. In this review, we emphasize the central role of epigenetic dysregulation in cancer pathogenesis, epigenetic changes in the cancer genome, and the latest advancements in cancer therapy, particularly the potential of epigenetic factors as biomarkers for early detection and their application in current cancer treatment modalities.