Role of epigenetic changes in hematological malignancies.

Inactivation of tumor suppressor genes is an important event contributing to the development of neoplasia. In addition to the classic genetic mechanisms of deletion or inactivating point mutations, growth regulatory genes can be functionally inactivated without alterations of the primary sequence by methylation of cytosine residues in the promoter regions of the genes. After introducing epigenetic phenomena in general and the molecular basis of DNA methylation in more detail, this review will present the broad spectrum of alterations in DNA methylation patterns found in hematopoietic malignancies. In addition, the implications for therapy and prognosis will be discussed.