Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0023473 (chronic myeloid leukemia)
 18,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Acute megakaryoblastic leukemia (AMkL) is a newly defined acute leukemia in which the differentiation of proliferating blasts is arrested at the megakaryocytic precursor stage. In order to clarify whether a target cell of leukemic transformation in AMkL is a cell committed to megakaryocytic lineage, or a multipotential stem cell, we examined AMkL patients with regard to: a) the presence of myelodyplastic features in residual erythroid and granulocytic cells, b) coexistence of myeloperoxidase (MPO)-positive blasts with megakaryoblasts, and c) the presence of the same chromosomal abnormality in erythroid and granuloid colony-forming cells as seen in megakaryoblasts. Regarding the former two items, results were compared with those from megakaryoblastic crisis of chronic myelocytic leukemia (CML-MkBC) and transient myeloproliferative disorder in Down syndrome (DS-TMD), which are thought to be multipotential stem cell disorders. Among 18 patients with AMkL, three, all complicating myelofibrosis, had marked myelodysplastic changes of erythroid series and/or granulocytic series. In 4 out of 7 patients with CML-MkBC, 5 out of 8 patients with DS-TMD, and 7 out of 18 patients with AMkL, MPO-positive blasts, even though rare, were observed in addition to PPO-positive blasts. All except one of these patients with AMkL also showed complicating myelofibrosis. In one case of AMkL with myelofibrosis, chromosomal analysis of cultured cells of individual colonies revealed that all the analysable metaphases from both CFU-GM and BFU-E had the same chromosomal abnormality as megakaryoblasts. This study has clarified that a considerable proportion of AMkL cases, particularly those with complicating myelofibrosis or showing acute myelofibrosis, arise against the background of a multipotential stem cell disorder, even if blasts are exclusively megakaryocytic in phenotype.
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PMID:Target cell of leukemic transformation in acute megakaryoblastic leukemia. 216 21

Using DNA staining with highly stable osmium-ammine-B, the blasts of AMKL were observed under an electron microscope, in comparison with AML, ALL, CML-MK crisis and TMD. The DNA within the nucleus of the megakaryoblasts was observed as a high electron-density substance and tended to be uniformly dispersed within the nucleus. DNA, associated with nucleoli, could be roughly divided in four types based on the presence or absence of peri-nucleolar clumps and intra-nucleolar clumps. In cases of AMKL, we often observed a type that did not have peri-nucleolar DNA clumps but did have DNA flecks within the nucleoli. By analytical evaluation there were no differences among cells from several subtypes of megakaryocytic leukemia, such as AMKL in children with Down's syndrome, AMKL in children without Down's syndrome, AMKL in adults, and CML-MK crisis. The DNA distribution of TMD blasts, which were self-limited and not malignant, resembled that of AMKL blasts.
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PMID:Ultrastructural investigation of DNA in megakaryoblastic leukemia by using osmium-ammine-B: comparison with several types of leukemia. 826 56