Cancer continues to be one of the leading causes of death and a major global health problem despite ongoing research efforts, advancement in medical technologies, and increased public health awareness. However, the understanding of human cancer as a heterogeneous disease has been significantly increased offering hope that the vital molecular and cellular mechanisms would pave the way for controlling cancer at its advanced stages. The transformation of normal cells into cancerous cells is a complex process achieved through a cascade of events and molecular modifications. A great deal of cancer research has been focusing on studying epigenetic alterations such as DNA methylation, histone modification, and non-coding RNA expression. These epigenetic changes modulate gene expression which is believed to play a potential role in cancer initiation, proliferation, and metastasis. This article aims to review how several aberrant epigenetic regulations impact gene expression and cellular reprogramming in cancer. It also discusses how hypomethylation can lead to increased expression of oncogenes and how hypermethylation silences key tumor suppressor genes. It also highlights how these aberrantly dysregulated genes can serve as potential therapeutic targets for cancer prevention and as biomarkers for early cancer detection.