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)

We examined clinical, morphologic, and cytogenetic features and ALL-1 (MLL, Htrxl, HRX) gene rearrangements in 17 cases of secondary leukemia that occurred 11 months to 9 years from diagnoses of primary cancers in children who received topoisomerase II inhibitors or developed secondary leukemias typical of those associated with this therapy. Primary diagnoses included nine solid tumors and eight leukemias. Ten secondary leukemias were acute myeloid leukemia (AML), one was of mixed lineage, two were acute lymphoblastic leukemia (ALL), and four presented as myelodysplasia. Of 15 cases with 11q23 involvement, 11 (73%) were cytogenetically identifiable; four cases had molecular rearrangement only. By Southern blot, rearrangements within the ALL-1 gene were similar to sporadic cases. The results of this analysis suggest the following: (1) In most pediatric cases of topoisomerase II inhibitor-associated leukemia, there is disruption of the breakpoint cluster region of the ALL-1 gene at chromosomal band 11q23. (2) Exposure histories vary in secondary 11q23 leukemia, as the only topoisomerase II inhibitor was dactinomycin in one case, and, in another case, no topoisomerase II inhibitor was administered. (3) There is clinical, morphologic, cytogenetic, and molecular heterogeneity in pediatric secondary 11q23 leukemia. (4) There are some survivors of pediatric secondary 11q23 leukemia, but the outcome is most often fatal.
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PMID:ALL-1 gene rearrangements in DNA topoisomerase II inhibitor-related leukemia in children. 775 57

The clinicopathological features and the prognostic significance of acute myeloid leukaemia (AML) with trisomy 11 are currently unknown. In this study we describe 15 adult AML cases with trisomy 11. Trisomy 11 was the sole chromosomal anomaly in eight cases; the remaining seven cases were characterized by +11 in association with other karyotypic aberrations. Patients ages ranged from 34 to 79 years. 12 patients were male; three were female. Although there was no correlation of trisomy 11 with any specific FAB subgroup [M2 (n = 7), M1 (n = 5), M4/5 (n = 2), M3 (n = 1)] less mature forms predominated. Immunologically, the leukaemic blasts showed a strikingly consistent stem cell phenotype with expression of HLA-DR, CD34 and the myeloid antigens (CD15, CD33 and/or CD13). In addition, two cases expressed the B-cell associated antigen CD19. The presence of trilineage dysplasia, suggesting the presence of an underlying myelodysplasia (MDS), was observed at presentation in five cases; in another case MDS was evident at relapse only. Unexpectedly, MLL gene rearrangements were observed in two of four cases characterized by trisomy 11 as the sole karyotypic abnormality; however, MLL aberrations were not identified in three cases with trisomy 11 accompanied by other karyotypic anomalies. The majority of patients in each subgroup (i.e. those with and without additional cytogenetic abnormalities) achieved a short first complete remission (CR) (mean 8 months) and failed to obtain a second CR. Only one patient in each trisomy 11 subgroup is in a continuous CR for > 34 months. These findings suggest that trisomy 11 leukaemia is characterized by a stem/progenitor cell immunophenotype with poor response to standard chemotherapeutic regimens and an unfavourable prognosis.
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PMID:Trisomy 11: an association with stem/progenitor cell immunophenotype. 779 46

Chromosome band 11q23 is frequently involved in acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) de novo, as well as in myelodysplastic syndromes (MDS) and lymphoma. Five percent to 15% of patients treated with chemotherapy for a primary neoplasm develop therapy-related AML (t-AML) that may show rearrangements, usually translocations involving band 11q23 or, less often, 21q22. These leukemias develop after a relatively short latent period and often follow the use of drugs that inhibit the activity of DNA-topoisomerase II (topo II). We previously identified a gene, MLL (myeloid-lymphoid leukemia or mixed-lineage leukemia), at 11q23 that is involved in the de novo leukemias. We have studied 17 patients with t-MDS/t-AML, 12 of whom had cytogenetically detectable 11q23 rearrangements. Ten of the 12 t-AML patients had received topo II inhibitors and 9 of these, all with balanced translocations of 11q23, had MLL rearrangements on Southern blot analysis. None of the patients who had not received topo II inhibitors showed an MLL rearrangement. Of the 5 patients lacking 11q23 rearrangements, some of whom had monoblastic features, none had an MLL rearrangement, although 4 had received topo II inhibitors. Our study indicates that the MLL gene rearrangements are similar both in AML that develops de novo and in t-AML. The association of exposure to topo II-reactive chemotherapy with 11q23 rearrangements involving the MLL gene in t-AML suggests that topo II may play a role in the aberrant recombination events that occur in this region both in AML de novo and in t-AML.
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PMID:Rearrangements of the MLL gene in therapy-related acute myeloid leukemia in patients previously treated with agents targeting DNA-topoisomerase II. 826 Jul 7

Seven secondary leukemia patients were treated for solid tumors or malignant lymphoma with anticancer drugs or radiation. We studied bone marrow samples from these patients by fluorescence in situ hybridization (FISH). Of the seven patients, three had increased signals for the ABL oncogene (9q34) on interphase nuclei and at metaphase. One of the three patients also had four signals for the CD3 (MLL) region (11q23). Whole painting probes revealed that these chromosomal regions were translocated onto structurally abnormal chromosomes, resulting in partial tri-, tetra- or penta-somy of these regions. We called this type of translocation "segmental jumping translocation (SJT)." SJT of the ABL oncogene was not detected in samples from 15 patients with de novo acute myelocytic leukemia (AML), 12 with myelodysplastic syndrome (MDS), or 20 with chronic myelocytic leukemia (CML) at the chronic phase. Furthermore, monosomy 7 was also found in the patients with the gene amplification. These results indicate that SJT of ABL and/or CD3 (MLL) genes is associated with the leukemogenesis of secondary leukemia. The SJT may be one mechanism of gene amplification.
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PMID:Frequent jumping translocations of chromosomal segments involving the ABL oncogene alone or in combination with CD3-MLL genes in secondary leukemias. 900 63

Trisomy 11 as a sole chromosomal abnormality is a rare aberration observed in myelodysplastic syndrome (MDS) or acute myeloblastic leukemia (AML). Recently a partial tandem duplication of the MLL gene, located on chromosome band 11q23, has been identified in de novo AML with trisomy 11. We describe a 72-year-old woman suffering from MDS-derived overt leukemia with trisomy 11 and a tandem duplication of the MLL gene. At first the patient was found to have myeloblasts with Auer rods in the peripheral blood and diagnosed as MDS, refractory anemia with excess of blasts in transformation (RAEB-T). After 2 months a picture of overt leukemia (AML; M2) developed as shown by an increased number of myeloblasts. Various chemotherapy regimens had little effect, and she died of disease progression 15 months after admission. During her clinical course, the chromosome analyses consistently showed 47,XX, +11. Southern blot analysis of leukemic blasts on admission and in accelerated phase revealed identical rearranged bands of the MLL gene. Fluorescence in situ hybridization analysis excluded the possibility of masked translocation of the MLL gene to other chromosomes. Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis using a forward exon 6 primer and a backward exon 3 primer demonstrated an in-frame fusion of exon 8 with exon 2. Our results indicated that a partial tandem duplication of exons 2-8 of the MLL gene could be observed in MDS-derived overt leukemia as well as de novo AML with trisomy 11.
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PMID:Tandem duplication of the MLL gene in myelodysplastic syndrome-derived overt leukemia with trisomy 11. 913 17

The recurrent translocation t(11;16)(q23;p13) has been reported to be associated with therapy-related acute leukemia. The MLL gene involved in other 11q23 abnormalities was also rearranged by this translocation. We analyzed two patients with myelodysplastic syndrome with t(11;16) and showed that the MLL gene on 11q23 was fused with CREB-binding protein (CBP) gene on 16p13 in these patients. The CBP gene encodes a transcriptional adaptor/coactivator protein and it is mutated in patients with Rubinstein-Taybi syndrome. The CBP gene is also involved in acute myeloid leukemia (AML) with t(8;16)(p11;p13). In-frame MLL-CBP fusion transcripts combine the MLL AT-hook motifs and DNA methyltransferase homology region with a largely intact CBP. Our results combined with the finding of the MOZ-CBP fusion in t(8;16)-AML suggest that the CBP gene may be associated with leukemogenesis through translocations.
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PMID:The t(11;16)(q23;p13) translocation in myelodysplastic syndrome fuses the MLL gene to the CBP gene. 916 31

We studied four patients with inv(11)(p15q22) associated with malignant myeloid diseases by using fluorescence in situ hybridization (FISH) with phage and cosmid probes mapped and ordered on 11q22-24. Two of the four patients had non-Hodgkin's lymphoma or acute lymphoblastic leukemia as the primary malignancy and had received cytotoxic chemotherapy, including topoisomerase II inhibitors. The other two had de novo acute myeloid leukemia or myelodysplastic syndrome. FISH analysis showed that all 11q breakpoints were located centromeric to the MLL gene and between cosmids CN2900 and CN1323. We identified a yeast artificial chromosome (YAC) clone that spanned the inv(11) breakpoints on 11q. From this YAC, we identified a P1 clone, which included the breakpoints in at least three of the four patients. It is highly likely that the same gene on the P1 clone is rearranged in leukemic cells of each patient. This gene may be one of the targets for topoisomerase II inhibitors.
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PMID:Inversion of chromosome 11 inv(11)(p15q22), as a recurring chromosomal aberration associated with de novo and secondary myeloid malignancies: identification of a P1 clone spanning the 11q22 breakpoint. 921 95

The involvement of 11q23-balanced translocations in acute leukemia after treatment with drugs that inhibit the function of DNA topoisomerase II (topo II) is being recognized with increasing frequency. We and others have shown that the gene at 11q23 that is involved in all of these treatment-related leukemias is MLL (also called ALL1, Htrx, and HRX). In general, the translocations in these leukemias are the same as those occurring in de novo leukemia [eg, t(9;11), t(11;19), and t(4;11)], with the treatment-related leukemias accounting for no more than 5% to 10% of any particular translocation type. We have cloned the t(11;16)(q23;p13.3) and have shown that it involves MLL and CBP (CREB binding protein). The CBP gene was recently identified as a partner gene in the t(8;16) that occurs in acute myelomonocytic leukemia (AML-M4) de novo and rarely in treatment-related acute myeloid leukemia. We have studied eight t(11;16) patients, all of whom had prior therapy with drugs targetting topo II with fluorescence in situ hybridization (FISH) using a probe for MLL and a cosmid contig covering the CBP gene. Both probes were split in all eight patients and the two derivative (der) chromosomes were each labeled with both probes. Use of an approximately 100-kb PAC located at the breakpoint of chromosome 16 from one patient revealed some variability in the breakpoint because it was on the der(16) in three patients, on the der(11) in another, and split in four others. We assume that the critical fusion gene is 5'MLL/3'CBP. Our series of patients is unusual because three of them presented with a myelodysplastic syndrome (MDS) most similar to chronic myelomonocytic leukemia (CMMoL) and one other had dyserythropoiesis; MDS is rarely seen in 11q23 translocations either de novo or with t-AML. Using FISH and these same probes to analyze the lineage of bone marrow cells from one patient with CMMoL, we showed that all the mature monocytes contained the fusion genes as did some of the granulocytes and erythroblasts; none of the lymphocytes contained the fusion gene. The function of MLL is not well understood, but many domains could target the MLL protein to particular chromatin complexes. CBP is an adapter protein that is involved in regulating transcription. It is also involved in histone acetylation, which is thought to contribute to an increased level of gene expression. The fusion gene could alter the CBP protein such that it is constitutively active; alternatively, it could modify the chromatin-association functions of MLL.
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PMID:All patients with the T(11;16)(q23;p13.3) that involves MLL and CBP have treatment-related hematologic disorders. 922 52

The recurring translocation t(11;16)(q23;p13.3) has been documented only in cases of acute leukemia or myelodysplasia secondary to therapy with drugs targeting DNA topoisomerase II. We show that the MLL gene is fused to the gene that codes for CBP (CREB-binding protein), the protein that binds specifically to the DNA-binding protein CREB (cAMP response element-binding protein) in this translocation. MLL is fused in-frame to a different exon of CBP in two patients producing chimeric proteins containing the AT-hooks, methyltransferase homology domain, and transcriptional repression domain of MLL fused to the CREB binding domain or to the bromodomain of CBP. Both fusion products retain the histone acetyltransferase domain of CBP and may lead to leukemia by promoting histone acetylation of genomic regions targeted by the MLL AT-hooks, leading to transcriptional deregulation via aberrant chromatin organization. CBP is the first partner gene of MLL containing well defined structural and functional motifs that provide unique insights into the potential mechanisms by which these translocations contribute to leukemogenesis.
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PMID:MLL is fused to CBP, a histone acetyltransferase, in therapy-related acute myeloid leukemia with a t(11;16)(q23;p13.3). 923 46

We describe two new human leukemia cell lines, MOLM-13 and MOLM-14, established from the peripheral blood of a patient at relapse of acute monocytic leukemia, FAB M5a, which had evolved from myelodysplastic syndrome (MDS). Both cell lines express monocyte-specific esterase (MSE) and MLL-AF9 fusion mRNA. Gene fusion is associated with a minute chromosomal insertion, ins(11;9)(q23;p22p23). MOLM-13 and MOLM-14 are the first cell lines with, and represent the third reported case of, MLL gene rearrangement arising via chromosomal insertion. Both cell lines carry trisomy 8 which was also present during the MDS phase, as well as the most frequent trisomies associated with t(9;11), ie, +6, +13, +19 variously present in different subclones. Despite having these features in common, differences in antigen expression were noted between the two cell lines: that of MOLM-13 being CD34+, CD13-, CD14-, CD15+, CD33+; whereas MOLM-14 was CD4+, CD13+, CD14+, CD15+, CD33+. Differentiation to macrophage-like morphology could be induced in both cell lines after stimulation with INF-gamma alone, or in combination with TNF-alpha, which treatment also induced or upregulated, expression of certain myelomonocyte-associated antigens, including CD13, CD14, CD15, CD64, CD65 and CD87. Together, these data confirm that both cell lines are likely to be novel in vitro models for studying monocytic differentiation and leukemogenesis.
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PMID:Two acute monocytic leukemia (AML-M5a) cell lines (MOLM-13 and MOLM-14) with interclonal phenotypic heterogeneity showing MLL-AF9 fusion resulting from an occult chromosome insertion, ins(11;9)(q23;p22p23). 930


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