Clinical experience with decitabine in North American patients with myelodysplastic syndrome

Spotlight on decitabine for myelodysplastic syndromes in Chinese patients

Myelodysplastic syndromes (MDSs) are a group of heterogeneous clonal hematopoietic stem cell malignancies with advanced median age. The silencing of tumor suppressor genes caused by DNA hypermethylation plays a crucial role in the pathogenesis of MDS. Decitabine, the available hypomethylating agent, is successfully used for the treatment and improves the outcome of MDS, and has become one of the most frequently administered disease-modifying therapies. With an aging population and a growing number of people exposed to benzene, the incidence of MDS has been increasing rapidly. The blinded regimen choice and the lack of a unified strategy create challenges for the treatment of MDS. Here, we present a review of clinical progress and prospects of decitabine treatment of MDS in the People’s Republic of China. We also discuss the optimization of therapy issues to improve the cure rate and prolong survival in patients with MDS.

Phenotypic plasticity and the epigenetics of human disease

It is becoming clear that epigenetic changes are involved in human disease as well as during normal development. A unifying theme of disease epigenetics is defects in phenotypic plasticity--cells' ability to change their behaviour in response to internal or external environmental cues. This model proposes that hereditary disorders of the epigenetic apparatus lead to developmental defects, that cancer epigenetics involves disruption of the stem-cell programme, and that common diseases with late-onset phenotypes involve interactions between the epigenome, the genome and the environment. Increased understanding of epigenetic-disease mechanisms could lead to disease-risk stratification for targeted intervention and to targeted therapies.

Strategies for achieving transfusion independence in myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are a group of complex diseases of the myeloid stem cell that result in chronic cytopenias. In some instances, these disorders may progress to acute myeloid leukemia. Patients with MDS frequently experience chronic, symptomatic anemia, and many become dependent on chronic transfusions of packed red blood cells. However, long-term transfusion dependence has clinical and economic consequences, including a potentially negative impact on patients' quality of life (QOL). Recently, studies have investigated various strategies to reduce or eliminate transfusion needs in MDS patients. Supportive measures with hematopoietic growth factors such as erythropoietin are often less effective in MDS-associated anemia than in anemia from other causes, but some patients may benefit from this approach. Treatment with other agents, such as antithymocyte globulin, azacitidine, decitabine, thalidomide, and lenalidomide, has resulted in transfusion independence in some subsets of MDS patients. Nurses who care for patients with MDS should be aware of the impact of transfusion dependence on the patient's QOL, as well as the benefits and risks of the various other treatment options available to these patients. Such knowledge will enable the nurse to provide accurate, relevant information, so that patients can make informed choices regarding treatment options for MDS.

Tumor suppressor gene methylation in follicular lymphoma: a comprehensive review

Transcriptional silencing of tumor suppressor genes, associated with DNA methylation, is a common epigenetic event in hematologic malignancies. Although DNA hypermethylation of CpG islands is well described in acute leukemias and myelodysplastic syndromes, much less is known of the specific methylation changes that commonly occur in follicular B cell lymphomas. Earlier methylation studies of follicular lymphoma involved only cell lines; however there is a growing literature of methylation changes in primary human FL samples. Published studies of primary follicular lymphoma specimens have demonstrated that: androgen receptor, SHP1, and death-associated protein kinase genes are commonly methylated. By contrast, the cyclin dependent kinase inhibitors p15, p16, and p57 are uncommon epigenetic events in follicular lymphoma. Methylation of cyclin dependent kinase inhibitors is more common in high grade lymphomas, and may be an important step in the progression and transformation of follicular lymphoma. Further methylation studies in follicular lymphoma should investigate the prognostic and therapeutic significance of these epigenetic changes and investigate methylation of other genes. Finally, reactivation of methylated tumor suppressor genes through the use of hypomethylating agents is a promising and novel approach to the treatment of indolent and transformed follicular lymphomas.