DNA methyltransferases and their roles in tumorigenesis

DNA methylation plays an important role in gene expression, chromatin stability, and genetic imprinting. In mammals, DNA methylation patterns are written and regulated by DNA methyltransferases (DNMTs), including DNMT1, DNMT3A and DNMT3B. Recent emerging evidence shows that defects in DNMTs are involved in tumor transformation and progression, thus indicating that epigenetic disruptions caused by DNMT abnormalities are associated with tumorigenesis. Herein, we review the latest findings related to DNMT alterations in cancer cells and discuss the contributions of these effects to oncogenic phenotypes.