Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023467 (acute myeloid leukemia)
 35,200 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cytogenetic studies have previously identified abnormalities of chromosome band 11q23 in many cases of infant acute leukemia. Recent studies by ourselves and others have demonstrated breakpoint clustering in acute leukemias bearing translocations involving 11q23, and a Drosophila trithorax gene homologue (called MLL, HRX, or ALL-1) has been shown to span the 11q23 breakpoints of these translocations. To determine if this gene is affected in infant acute myeloid leukemia (AML), we have analyzed 26 infant AML cases for molecular alterations of this 11q23 gene. 15 out of 26 cases studied (58%) showed rearrangement of the MLL gene at the molecular level, and these rearrangements were clustered within an approximately 11-kb region containing nine exons of this gene. Moreover, 14 of the 15 cases with 11q23 rearrangements (93%) had myelomonocytic or monocytic phenotypes (M4 or M5 FAB subtypes, respectively), both of which are associated with a poor prognosis in childhood AML. In contrast, only 1 of 11 nonrearranged cases had an M4 or M5 phenotype (P = 0.00002). Rearrangement also correlated significantly with hyperleukocytosis (P = 0.02), another clinical parameter associated with poor outcome in this disease. Our results demonstrate that molecular rearrangements of MLL are common in M4 or M5 infant AML, and suggest that alteration of this gene may result in abnormal control of proliferation and differentiation in monocytic progenitor cells.
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PMID:Molecular rearrangements of the MLL gene are present in most cases of infant acute myeloid leukemia and are strongly correlated with monocytic or myelomonocytic phenotypes. 828 16

The responses of blast cells from 52 cases of pediatric acute myeloid leukemia (AML) and 81 cases of acute lymphocytic leukemia (ALL) to 11 hematopoietic growth factors were determined using a 3H-thymidine assay. There was considerable variation in the ability of growth factors to stimulate thymidine incorporation among individual cases of AML. Blasts from almost one half of the patients (25 out of 52) with AML were responsive to growth factors such as IL-3, G-CSF, or GM-CSF. Alternatively, 37% of AML cases (19 out of 52) showed little (< 2.5 times background) thymidine incorporation in the presence of growth factors; such cases were classified as nonresponsive. All AML cases expressing mixed-lineage characteristics (expression of lymphoid-associated antigens) were non-responsive. In 15% of the cases (9 out of 52), blasts incorporated high levels of thymidine without growth factors and there was no increase in 3H-thymidine incorporation in the presence of growth factors. Such cases were classified as independent. The response to growth factors did not correlate with other biological characteristics such as the FAB morphologic classification or specific chromosomal abnormalities. In striking contrast to AML cases, blast sells from only a few of the ALL cases studied showed any response to growth factors. These results demonstrate that growth factor responsiveness is a unique biological characteristic of the leukemic blasts and does not appear to correlate with other easily identified biological features.
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PMID:Effects of recombinant human hematopoietic growth factors on leukemic blasts from children with acute myeloblastic or lymphoblastic leukemia. 832 Oct 18

The 8;21 translocation is one of the most common chromosomal translocations in acute myelogenous leukemia (AML), accounting for 40% of pediatric AML with French-American-British (FAB)-M2 morphology. The chromosomal breakpoints have recently been identified at the molecular level and shown to involve the AML1 gene on chromosome 21 and the ETO gene on chromosome 8. Translocation results in the consistent fusion of these genes on the der(8) chromosome, resulting in the production of a novel chimeric gene and message. Using oligonucleotide primers derived from the AML1 and ETO cDNAs, we were able to amplify a specific fusion transcript from 26 of 26 patients with t(8;21) by a reverse transcriptase polymerase chain reaction (PCR) approach. DNA fragments of identical size were generated from each case including two with complex translocations. Studies on the sensitivity and specificity of this approach show that PCR analysis can be used as a rapid, accurate, and sensitive means for detecting this chromosomal abnormality, and for following the patients' response to therapy.
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PMID:An AML1/ETO fusion transcript is consistently detected by RNA-based polymerase chain reaction in acute myelogenous leukemia containing the (8;21)(q22;q22) translocation. 849 24

Expression of the multidrug resistance (MDR-1) gene product, P-glycoprotein (P-170), and the stem cell antigen, CD34, at diagnosis were determined using monoclonal antibodies (MoAbs) MRK-16 and 12.8 respectively, in 130 pediatric acute myeloid leukemia (AML) patients entered onto Childrens Cancer Group (CCG) study CCG-2891. Fluorescein isothiocyanate (FITC) as a second step reagent was employed for the measurement of P-170 expression since it is commonly used in clinical laboratories. Nine of 30 (30%) infant ( < 1 year of age) de novo specimens expressed P-170 at levels > or = 20% of control cells. In contrast, eight of 100 (8%) AML samples from older children ( > or = 1 year of age) expressed the multidrug resistance surface protein at diagnosis. With the exception of one infant, all de novo samples that expressed P-170 also expressed CD34. Pediatric patients of any age with positive P-170 expression using MoAb MRK-16 with a FITC-conjugated second step reagent fared no worse than remaining patients treated on the same treatment with regard to induction failure, incidence of relapse, event-free survival, or overall survival. Further investigation is necessary to determine whether P-170 assay systems with greater sensitivity will distinguish pediatric AML patients with poor prognosis.
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PMID:Cell surface expression of the multidrug resistance P-glycoprotein (P-170) as detected by monoclonal antibody MRK-16 in pediatric acute myeloid leukemia fails to define a poor prognostic group: a report from the Childrens Cancer Group. 860 15

Resistance to chemotherapy is a major problem in acute myeloid leukemia (AML). An important resistance mechanism in adult AML is active drug efflux mediated by the multidrug resistance protein-1 (MDR1). To determine if MDR1 is important in childhood AML, we examined MDR1 expression and functional dye/drug efflux in 20 pediatric/adolescent AML patients; results were correlated with cytogenetics and clinical outcome. Using flow cytometry, MDR1 protein expression on the leukemic blasts was measured with the antibody MRK16, while efflux was measured by extrusion of the fluorescent dye DiO(C2)3 in the presence/absence of cyclosporin A (CsA). Six of 20 cases expressed MDR1. While all six MDR1+ cases were efflux+, three of 14 MDR1- cases also demonstrated efflux. Both MDR1 and efflux were strongly correlated with the t(8;21). All six MDR1 +/efflux+ cases and 2/3 MDR1 -/efflux+ cases had a t(8;21), while no MDR1-/efflux- cases had a t(8;21) (P < 0.0005). This correlation between MDR1, efflux, and the t(8;21) in pediatric AML was not found in 11 adult t(8;21) cases similarly studied. Although the clinical relevance of MDR1 in pediatric AML awaits larger studies, our results suggest a biologic subset of pediatric AML patients may benefit from regimens which include MDR1-reversing agents or non-MDR1 substrates.
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PMID:Multidrug resistance-1 (MDR1) expression and functional dye/drug efflux is highly correlated with the t(8;21) chromosomal translocation in pediatric acute myeloid leukemia. 870 31

This concise review focuses on the new possibilities offered by molecular biology for the accurate diagnosis of chromosome abnormalities characteristic of some acute myeloid leukemias. Translocations t(8;21), t(15;17) and inv(16) may account for up to 30% of all cases of adult and childhood AML and their identification either by cytogenetics or molecular techniques is becoming of crucial importance for the routine diagnosis and treatment of AML, since they allow the identification of patients whose likelihood of cure is remarkably better. In these patients, the need of myeloablative protocols, supported by autologous or allogeneic transplantation, may not be required at least in first remission, and this can prevent the delivery of inappropriately toxic therapies. On the other hand, patients whose blasts are showing rearrangements of 11q23 band had a significantly worse prognosis and its precise identification may help the accrual to more appropriate and aggressive therapeutic protocols. These molecular markers are offering new tools, which are extremely sensitive, for the detection of minimal residual disease (MRD) for a growing number of AML patients. Although very promising in acute promyelocytic leukemia, the clinical significance and utility to investigate MRD persistence may be different for other the AML subgroups and caution should be taken in transferring these data to the clinical practice outside prospective controlled clinical trials.
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PMID:Molecular diagnosis and monitoring of acute myeloid leukemia. 896 Jan 4

Treatment results were evaluated in 45 children with acute myeloblastic leukemia (AML) treated on the ANLL-9205 protocol of the Children's Cancer Leukemia Study Group (CCLSG, Japan). In this protocol, terarubicin (THP-ADR), vincristine and continuous infusion of cytosine arabinoside (Ara C) were applied for remission induction therapy (AVC), and VP16+ high dose Ara C were used sequentially for 32 or 48 weeks. Eleven patients received stem cell transplantation. Thirty-eight out of the 43 eligible patients (88.4%) achieved complete remission, and the overall 3-year event-free survival (EFS) was 55.6% (S.E.,10%). This favorable response was attributed mainly to the high induction rate of patients with the M5, M7 FAB subtypes and higher WBC counts (> or = 10 x 10(9)/L). There was no difference in the 3-year EFS of these patients who discontinued treatment between 32 weeks and 48 weeks. Serious toxicities were not observed in this study. These findings suggest that the ANLL-9205 protocol is an effective and safe treatment regimen for childhood AML. When comparing the treatment period of 32 or 48 weeks, the difference was not statistically significant.
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PMID:[Myelogenous leukemia in children. ANLL9205 study by Children's Cancer and Leukemia Study Group (CCLSG)]. 905 63

To study prognostic factors in infant acute myeloid leukemia (AML), we analyzed 44 children treated on Childrens Cancer Group protocols for MLL gene rearrangement by Southern blot, cytogenetic 11q23 abnormalities, and reactivity with monoclonal antibody 7.1. This antibody detects the human homologue of the rat NG2 chondroitin sulfate proteoglycan molecule, which has previously been reported to be expressed on human melanoma. NG2 has been found to be expressed on human leukemic blasts but not on other hematopoietic cells. In childhood AML, NG2 cell surface expression correlated with poor outcome and with some but not all 11q23 rearrangements. In childhood acute lymphoblastic leukemia, NG2 expression correlated with poor outcome and with balanced 11q23 translocations. In this study, 29 of 44 (66%) of infants with AML showed MLL rearrangement and, as expected, this group had a high incidence of French-American-British M4/M5 morphology (22/29). Of the cases tested, 35.1% (13/37) were NG2 positive. All (13/13) NG2-positive cases were rearranged at MLL, whereas only 46% (11/24) of NG2-negative cases had MLL rearrangement. NG2 expression did not correlate with poor outcome (P = .31); there was a trend towards a worse outcome with MLL rearrangement (P = .13). Thus monoclonal antibody 7.1 does not detect all cases of MLL rearrangement in infant AML.
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PMID:MLL gene rearrangement, cytogenetic 11q23 abnormalities, and expression of the NG2 molecule in infant acute myeloid leukemia. 916 Jun 87

Granulocytic sarcomas are localized deposits of myeloid leukemia cells that may precede or occur concurrently with disseminated disease. In either event, the origins of the cells comprising the malignancy are the same. Published reports of granulocytic sarcomas have described, in the majority of cases, a morphology typical of AML-M2 and the presence of the t(8;21)(q22;q21) typical of that FAB type. In a smaller number of cases, the inv(16)(p13q22) characteristic of AML-M4 has been recorded in cells with a myelomonocytic appearance. We report two patients with granulocytic sarcomas showing monocytic morphology in which the malignant cells showed t(9;11)(p22;q23) typical of AML-M5. This abnormality is seen in up to 7% of childhood AML, but has not previously been reported in granulocytic sarcoma. The detection of this cytogenetic abnormality facilitated the precise characterization of the malignant cells and selection of the most appropriate therapy, emphasizing the value of cytogenetic analysis in cases of granulocytic sarcoma.
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PMID:Granulocytic sarcoma with translocation (9;11)(p22;q23): two cases. 921 17

Acute myeloid leukemia (AML) comprises 15%-20% of childhood acute leukemia cases. The long-term disease free survival (DFS) in childhood AML is poor with standard chemotherapy alone. Early intensive chemotherapy is generally regarded to be necessary for achieving high complete remission (CR) rates. Recent experience has shown that incorporation of early intensification with high-dose melphalan conditioning and autologous bone marrow transplantation (BMT) during the first remission significantly improves long-term DFS in children with AML. In this article, we report the use of autologous BMT for treatment of a three-and-half year old child with acute promyelocytic leukemia (APL or M3) in second remission. The patient was conditioned with high-dose melphalan of 180 mg/kg prior to bone marrow reinfusion. A total of 4.0 x 10(7)/kg mononuclear cells and 1.07 x 10(5)/kg granulomonocytic colony forming units (CFU-GM) were infused. Haematopoietic stem cells were enriched by almost 20-fold after the separation and cryopreservation procedures. Haematological recovery was achieved four-and-a-half weeks post-BMT. She has remained in complete remission 18 months after transplantation. Our experience in this patient indicates that this procedure can be used in second remission and it may provide a better alternative for the management of childhood AML in Singapore.
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PMID:Autologous bone marrow transplantation in a child with acute promyelocytic leukemia in second remission. 936 89


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