Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0026986 (myelodysplastic syndrome)
 14,926 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Acute promyelocytic leukaemia (APL) is characterised by chromosomal rearrangements of 17q21, leading to fusion of the gene encoding retinoic acid receptor alpha (RARalpha) to a number of alternative partner genes (X), the most frequent of which are PML (>95%), PLZF (0.8%) and NPM (0.5%). Over the last few years, it has been established that the X-RARalpha fusion proteins play a key role in the pathogenesis of APL through recruitment of co-repressors and the histone deacetylase (HDAC)-complex to repress genes implicated in myeloid differentiation. Paradoxically, the X-RARalpha fusion protein has the potential to mediate myeloid differentiation at pharmacological doses of its ligand (all trans-retinoic acid (ATRA)), which is dependent on the dissociation of the HDAC/co-repressor complex. Arsenic compounds have also been shown to be promising therapeutic agents, leading to differentiation and apoptosis of APL blasts. It is now apparent that the nature of the RARalpha-fusion partner is a critical determinant of response to ATRA and arsenic, underlining the importance of cytogenetic and molecular characterisation of patients with suspected APL to determine the most appropriate treatment approach. Standard protocols involving ATRA combined with anthracycline-based chemotherapy, lead to cure of approximately 70% patients with PML-RARalpha-associated APL. Patients at high risk of relapse can be identified by minimal residual disease monitoring. The challenge for future studies is to improve complete remission rates through reduction of induction deaths, particularly due to haemorrhage, identification of patients at high risk of relapse who would benefit from additional therapy, and identification of a favourable-risk group, for which treatment intensity could be reduced, thereby reducing risks of treatment toxicity and development of secondary leukaemia/myelodysplasia. With the advent of ATRA and arsenic, APL has already provided the first example of successful molecularly targeted therapy; it is hoped that with further understanding of the pathogenesis of the disease, the next decade will yield further improvements in the outlook for these patients.
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PMID:The molecular pathogenesis of acute promyelocytic leukaemia: implications for the clinical management of the disease. 1264 21

The hematopoietic system, due to intensive cells proliferation, is very sensitive to toxic substances. Many chemicals, including benzene, pesticides (dithiocarbamines), ethylene oxide and metals (mercury, cadmium, chrome, cobalt, lead, aluminum) exert their toxic effect on the hematopoietic system. Exposure to each of these substances may occur in the work place due to environmental pollution and in municipal or residential areas. Exposure to lead, aluminum, cadmium, and benzene results in the incidence of anemia. In addition, exposure to benzene and its metabolites leads to myelodysplastic syndromes, leukemia, lymphomas and bone marrow aplasia. Ethylene oxide induces neoplasm of the hematopoietic system and lymphomas, especially non-Hodgkin lymphoma. Arsenic compounds act like immunosuppressants. Mercury and chrome affect the immune system by immunosuppression and by evoking autoimmune reactions. Dithiocarbamates are suspected to induce leukemia. An analysis of the pathophysiology of individual substances reveal universal toxic mechanisms. In this paper, the authors discuss the pathomechanism of toxic effects of the aforesaid chemicals on the haematopoietic system and peripheral blood cells from the viewpoint of mutagenesis, apoptosis, myelotoxicity, anemia, immunomodulation, and individual sensitivity.
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PMID:[Effect of metals, benzene, pesticides and ethylene oxide on the haematopoietic system]. 1621 39

Arsenic and its derivatives have been used for medicinal purposes for thousands of years. Arsenic trioxide has demonstrated remarkable activity in the treatment of acute promyelocytic leukemia (APL), for which it can bring about complete remissions (CR) in > 80% of patients with relapsed disease, and molecular remission in 90% of those who enter a CR. Clinical trials have explored its use in the first-line setting and as part of consolidation therapy for de novo APL, for which it appears to provide an event-free and overall survival advantage. Two multicenter trials have examined its use in the treatment of the myelodysplastic syndromes; as a single agent, it yields responses in 20% of patients, and smaller trials have provided evidence for its use in non-APL acute myeloid leukemia populations in combination with other drugs such as gemtuzumab ozogamicin, ascorbic acid, and cytarabine.
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PMID:New data with arsenic trioxide in leukemias and myelodysplastic syndromes. 1828 65

Arsenic has been used for more than 2,000 years in the treatment of a variety of medical conditions, including plague, hysteria, syphilis, and cancer. Numerous potential mechanisms of action have been identified. Arsenic trioxide has remarkable efficacy in acute promyelocytic leukemia and is approved by the US Food and Drug Administration for this indication. It has also been studied in acute myeloid leukemia (AML), myelodysplastic syndrome (MDS), and multiple myeloma and has limited single-agent efficacy in these diseases. We have completed a phase I/II trial of arsenic trioxide combined with low-dose ara-C (LDAC) in 49 patients with Int-2/high-risk MDS and 64 patients age 60 years and older with untreated AML. The regimen was generally well tolerated and complete remissions were observed in both MDS and AML patients, including in patients with poor baseline performance status and unfavorable cytogenetics. Manuscript has been accepted for publication.
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PMID:Arsenic and old lace: novel approaches in elderly patients with acute myeloid leukemia. 1876 Jul 7

For more than 2,000 years, arsenic and its derivatives have shown medical utility. Owing to the toxicities and potential carcinogenicity of arsenicals, their popularity has fluctuated. The exact mechanism of action of therapeutic arsenic is not well characterized but likely to involve apoptosis, generation of reactive oxygen species, inhibition of intracellular transduction pathways, and cell functions. Arsenic trioxide has received approval for use in patients with relapsed acute promyelocytic leukemia for remission induction. Arsenic has additionally shown activity in a range of solid tumors, myelodysplastic syndrome, multiple myeloma, and in autoimmune diseases. The following is a review of the history of arsenic, its cellular metabolism, pharmacology, genetic basis of disposition, associated toxicities, and clinical efficacy.
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PMID:The evolving use of arsenic in pharmacotherapy of malignant disease. 2349 3