The epigenetic regulation is important for the understanding of cancer mechanism. In cancer development, the epigenetic alterations such as methylation and acetylation occurred. As methylated DNA regulates the gene expression, molecular pathway networks dynamically change in cancer. Furthermore, microRNAs expressed in the cells and secreted from the cells regulate the gene expression to modulate the signaling cascade. In this special issue, the epigenetic regulation in cancer is main focus of the topics.