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)

Mutation of the ras oncogenes is the most commonly detected molecular abnormality in acute myelogenous leukemia and myelodysplastic syndromes (MDS). This molecular event may either be acquired by different subclones or by all malignant cells. The availability of the ras p21 monoclonal antibody Y13 259 makes possible the direct study of the distribution of the ras gene product in human malignant cells. The bone marrow smears from 41 patients with MDS were analysed by two independent observers after treatment with MoAb Y13 259, biotinylated goat antirat IgG, streptavidin, peroxidase and staining with diaminobenzidine. A high proportion of strongly positive smears was found among patients with MDS. This positivity was found in 25% of refractory anemia, in 80% of the refractory anemias with excess of blasts, and in 90% of those in transformation, while all 7 cases with chronic myelomonocytic leukemia were found positive. The percentage of positivity may suggest that activation of ras oncogene in associated with disease progression.
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PMID:Analysis of immunohistochemical results of the ras oncogene product p21 in myelodysplastic syndromes. 835 32

Three cases of secondary (therapy-related) hematologic malignant conditions were identified among 95 children as old as 18 years of age; the cases were diagnosed between 1984 and 1990 and consisted of acute lymphoblastic leukemia, acute myeloid leukemia (AML), and myelodysplastic syndrome (MDSs). They constituted 10% of all new cases of AML and MDS seen at the University Hospitals of Cleveland during this time and were not related to congenital factors. The primary malignant conditions were malignant thoracopulmonary tumor (Askin tumor), neuroblastoma, and Burkitt's lymphoma. The secondary hematologic disorders all showed a prominent monocytic component: acute monocytic leukemia, MDSs evolving to acute myelomonocytic leukemia, and chronic myelomonocytic leukemia. The mean interval between treatment for the primary malignant condition and the onset of secondary disease was 36 months. All had received cyclophosphamide and an epipodophyllotoxin for the primary tumor; two were treated with radiation therapy. Cytogenetic abnormalities included del(5), del(13), t(1;6), and t(9;11)(p22[symbol:see text]3). The survival time after the onset of secondary disease was short.
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PMID:Myelodysplastic syndrome and acute myeloid leukemia after treatment for solid tumors of childhood. 837 35

It has recently been suggested that autocrine production of hematopoietic regulatory molecules can modulate the cardinal features of many leukemic states: excessive proliferation of the neoplastic cells and suppression of the normal elements. We therefore analyzed samples obtained from 57 patients with a variety of hematologic malignancies (21, acute myelogenous leukemia; 14, acute lymphoblastic leukemia; 12, Philadelphia chromosome-positive chronic myelogenous leukemia [blast phase] or acute leukemia; 5, chronic lymphocytic leukemia; and 5, chronic myelomonocytic leukemia) for expression of interleukin-1 beta (IL-1 beta) and tumor necrosis factor-alpha (TNF-alpha) transcripts on Northern blots. TNF-alpha mRNA was discerned in almost half of the samples (47%), and was expressed in some patients with every type of leukemia, except T-cell acute lymphoblastic leukemia (ALL). Expression occurred with great frequency in samples (12 of 15 [80%]) from monocytic (acute or chronic) leukemias, and from advanced chronic lymphocytic leukemia (4 of 5 samples [80%]). IL-1 beta transcripts were detected in 20 of 57 samples (35%). Its presence, like that of TNF-alpha, was ubiquitous, and only chronic lymphocytic leukemia and T-cell acute lymphoblastic leukemia cells consistently failed to produce IL-1 beta message. Therefore it appears that TNF-alpha and/or IL-1 beta mRNA can be found in the leukemic cells from a substantial subset of patients with B cell-derived acute lymphoblastic leukemia as well as with chronic and acute myeloid, monocytic or lymphocytic leukemias. Because these cytokines have potent direct and indirect effects on normal and malignant hematopoiesis, their widespread constitutive expression by neoplastic blood cells may play a fundamental role in driving the leukemic process.
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PMID:Ubiquitous expression of cytokines in diverse leukemias of lymphoid and myeloid lineage. 841 62

Retinoic acid exhibits effects on the proliferation and differentiation of many hematopoietic cells. Cellular responsiveness to retinoic acid (RA) is conferred through two distinct classes of nuclear receptors, the RA receptors (RARs) and the retinoid X receptors (RXRs). The RARs bind to both 9-cis- and all-trans-RAs, but 9-cis-RA alone directly binds and activates RXR. This suggested that 9-cis-RA could have expanded hematopoietic activities as compared with all-trans-RA. We compared the abilities of 9-cis- and all-trans-RAs to induce differentiation and inhibit proliferation of three acute myelogenous leukemia (AML) cell lines and fresh leukemic cells from 28 patients and found that: (1) 9-cis-RA in general was more potent than all-trans-RA in suppressing the clonal growth of two AML cell lines and 17 AML samples from patients, including four from individuals with acute promyelocytic leukemia (APL). Eleven leukemic samples, including three from patients with chronic myelogenous or chronic myelomonocytic leukemia, were relatively refractory to both retinoids. (2) The range of activities of both retinoids was similar except that the clonal growth of samples from three AML patients were inhibited by 9-cis-RA, but not by all-trans-RA. (3) Both retinoids inhibited the clonal proliferation of leukemia cells without necessarily inducing their differentiation; in fact, the only fresh AML cells that were able to undergo differentiation were from patients with APL and one individual with M2 AML. (4) Both retinoids enhanced myeloid and erythroid clonal growth from normal individuals, and 9-cis-RA showed slightly more stimulation of the myeloid clonal growth than did the all-trans-RA. Our study suggests that 9-cis-RA is worthy of further study for the treatment of selected individuals with AML.
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PMID:9-cis-retinoic acid: effects on normal and leukemic hematopoiesis in vitro. 842 82

Most studies of the clonal origin of the underlying lesion(s) and all investigations using X-inactivation, have concluded that the myelodysplastic syndromes arise from a multipotent stem cell. Non-random chromosomal abnormalities, particularly deletions of 5q and 7q, are common, most notably in therapy related MDS. Progression to AML is also frequently accompanied by increased genomic instability as evidenced by the emergence of multiple karyotypic abnormalities. While some evidence hints at the presence of tumour suppressor genes on chromosomes 5, 7, 20 and 12, no such genes have yet been identified. The search for point mutations in known oncogenes has concentrated on two oncogenes RAS and c-FMS. Point mutation frequency generating active forms of RAS oncogenes is approximately 40% in MDS overall, up to 80% in studies of CMML. 60% of all MDS RAS mutation involves a G to A transition, producing a substitution of aspartate for glycine at a frequency of 50% (of total ras mutants). RAS mutation is associated with progression to AML, although the presence of a RAS point mutation alone is neither necessary nor sufficient for leukaemic transformation. Mutation of c-FMS is also more common in CMML in comparison to other MDS subtypes and, as yet, point mutation potentiating the response of the receptor to CSF-1 (codon 969) has been found more frequently than point mutation resulting in permanently activated receptor (codon 301). However, recent work has identified additional mutations which produce transforming proteins, and mutation rates at these sites may be relevant in MDS.
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PMID:Myelodysplastic syndromes: from morphology to molecular biology. Part II. The molecular genetics of myelodysplasia. 849 99

We report two cases of extramedullary myeloid cell tumor that arose in patients with chronic myelomonocytic leukemia. In both cases, the tumors were difficult to recognize histologically because the neoplasms lacked cytological evidence of granulocyte maturation, such as cytoplasmic granulation or eosinophilic myelocytes, and the Leder stains for chloroacetate esterase were negative. Immunohistochemical studies were necessary to establish the correct diagnosis. The neoplastic cells in both tumors expressed myeloperoxidase, lysozyme, and CD43 and were negative for B-cell, T-cell, and other nonhematopoietic antigens tested. We report these cases to emphasize that extramedullary myeloid cell tumors may rarely precede transformation to acute myeloid leukemia in patients with chronic myelomonocytic leukemia. Extramedullary myeloid cell tumors of monocytic lineage may be difficult to recognize in routine and Leder-stained sections, and immunohistochemical studies may be essential for establishing the diagnosis.
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PMID:Extramedullary myeloid cell tumors arising in the setting of chronic myelomonocytic leukemia. A report of two cases. 855 47

Microsatellites are highly polymorphic, short-tandem repeat sequences dispersed throughout the genome. Instability of these repeat sequences at multiple gentic loci may result from mismatch repair errors and occur in hereditary nonpolyposis colorectal cancer and several other sporadic cancers, including chronic myelocytic leukemia as it progresses to blastic crisis. We investigated whether genetic instability occurred as myelodysplasia progressed to acute myelocytic leukemia. To this end, we studied microsatellite instability in 20 patients with myelodysplastic syndrome (MDS). These included five patients with refractory anemia (RA), three with refractory anemia with ringed sideroblast (RARS), nine with refractory anemia with excess blasts (RAEB) and three with chronic myelomonocytic leukemia (CMML). All of these patients transformed to acute myelocytic leukemia (AML) of various subtypes: three patients with M1, 11 with M2 and six patients with M4 (according to FAB classification). The DNA from both the MDS and AML phases of their disease was analyzed at 16 loci, and only four microsatellite instabilities were found in the 240 paired samples (1.6%) analyzed. These results indicate that mismatch repair errors such as microsatellite instability are not important in the evolution of MDS to AML.
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PMID:Infrequent microsatellite instability during the evolution of myelodysplastic syndrome to acute myelocytic leukemia. 862 9

High-dose methylprednisolone (HDMP) has been shown to induce differentiation of myeloid leukemic cells with a remarkable antileukemic effect in children with various subtypes of acute myeloblastic leukemia (AML), therefore we used HDMP in the treatment of four children with myelodysplastic syndrome (MDS). Two patients had refractory anemia with an excess of blasts in transformation (RAEB-t) with extramedullary infiltration (EMI), one had chronic myelomonocytic leukemia with pleural effusion, and one had RAEB. HDMP was administered orally at a single dose of 20-30 mg/kg/day combined with low-dose cytosine arabinoside (LD Ara-C) (10 mg/m2, 12-hourly s.c.) for 2 weeks. The treatment continued with mitoxantrone (10 mg/m2, i.v.) and Ara-C (5 mg/kg, i.v.) once a week for four doses followed by maintenance chemotherapy. All patients achieved hematologic remission 2-4 weeks after initiation of treatment. Extramedullary infiltration disappeared in all cases within 2 weeks to 3 months after initiation of therapy. With the exception of two patients who relapsed 6 and 24 months after remission, treatment could be stopped in others who remained in remission for 36 months without evidence of EMI; 6 months later one of them developed myelodysplastic relapse (RAEB). No side effects related to HDMP treatment were noted, but hyperleukocytosis developed in two patients who initially had high WBC counts. We suggest that the addition of HDMP with or without LD Ara-C to cytotoxic chemotherapy offers a promising alternative in cases not considered suitable for bone marrow transplantation.
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PMID:High-dose methylprednisolone, low-dose cytosine arabinoside, and mitoxantrone in children with myelodysplastic syndromes. 865 63

Between December 1981 and March 1994, 24 patients with a myelodysplastic syndrome (MDS) underwent allogeneic bone marrow transplantation (BMT) for RA with trilineage dysplasia (n = 4), CMML (n = 1), RAEB (n = 4), RAEBt (n = 9) and AML following MDS (n = 6). Fifteen patients (two RAEB, seven RAEBt and six sAML) received chemotherapy before BMT resulting in complete remission in 10 patients (six RAEBt and four sAML) at the time of BMT. Sixteen marrow donors were genotypically HLA-identical siblings. Remaining donors were other family members (five) or unrelated donors (three). The status of the underlying disease at the time of conditioning was the major factor determining long-term survival. The disease-freed survival of RA patients and patients presenting with RAEB, RAEBt and AML but transplanted in complete remission, was respectively 50 and 60%. On the contrary, none of the nine high-risk MDS patients transplanted with persistent disease, survived. Outcome after transplantation with alternative donors was inferior with one long-term survivor, mainly related to the high incidence of severe acute GVHD and its accompanying infectious complications. Six patients relapsed resulting in an actuarial probability of relapse of 28%. Twelve patients died of transplant-related complications leading to a non-relapse mortality at 5 years of 50%. At present eight patients are alive and disease-free 20 to 132 months post-transplantation resulting in an actuarial 5-year disease-free survival of 40.7%. Our results suggest that allogeneic bone marrow transplantation is a feasible treatment option for patients with MDS. However, improvement in GVHD prophylaxis and supportive care to reduce transplant-treated mortality and improved relapse prevention are imperative.
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PMID:Treatment of patients with myelodysplastic syndromes with allogeneic bone marrow transplantation from genotypically HLA-identical sibling and alternative donors. 873 92

The survival, proliferation, differentiation and function of normal hematopoietic cells are negatively and positively controlled by various cytokines. Survival and proliferation of leukemic cells appears to be influenced, at least in vitro, by several cytokines. Among the different hematopoietic cell lineages, megakaryocytopoiesis represents a complex and unique hematopoietic system that is thought to be supported by some well-known cytokines; however, the hypothetical lineage-specific main regulator of platelet production, termed thrombopoietin (TPO) had remained elusive. Recently, characterization of the proto-oncogene c-mpl revealed structural homology with the hematopoietic cytokine receptor superfamily, specific expression on cells of the megakaryocytic lineage and functional involvement in megakaryocytopoiesis. Several groups purified and cloned the MPL ligand. Extensive in vitro and in vivo studies have shown that the MPL ligand has activity in stimulating both megakaryocytopoiesis and platelet production proving that this ligand is the long-sought growth factor TPO itself. The MPL receptor was found at the mRNA and/or protein level in 40-80% of primary acute myeloid leukemia (AML) cases in various series. MPL expression was not limited to certain morphological FAB types, although the highest percentages were seen in the M6 (erythroid) and M7 (megakaryocytic) subclasses. Among the myelodysplastic syndromes (MDS), MPL expression was detected in one third of the cases, in particular in refractory anemia with excess of blasts and chronic myelomonocytic leukemia. Lymphoid malignancies such as acute lymphoblastic leukemia (ALL), non-Hodgkin's lymphoma (NHL) and myeloma were MPL-negative. Among the large panel of human leukemia-lymphoma cell lines studied, MPL expression occurred predominantly in lines with erythro-megakaryocytic phenotypes. Nearly all primary and continuously cultured non-hematopoietic solid tumor samples were negative for MPL expression. A significant portion of AML cases and of erythroid, megakaryocytic and myeloid leukemia cell lines co-expressed TPO and MPL mRNA transcripts, although no biologically active TPO appeared to be secreted by these cells. In several studies TPO induced in vitro proliferation of 14-37% of primary AML cases, predominantly of the M2 and M7 subtypes. TPO significantly enhanced the cytokine-induced growth of AML cells in a substantial fraction of cases responsive to GM-CSF, IL-3, IL-6 or SCF. While none of 30 growth factor-independent erythro-megakaryocytic leukemia cell lines responded to TPO with increased proliferation, TPO strongly augmented the growth of several constitutively cytokine-dependent cell lines (eg HU-3, M-07e, TF-1) which can be made TPO-dependent and used as bioassays. Neither in primary cells nor in cell lines did TPO appear to induce any signs of morphological, functional or immunological differentiation. Expression of the MPL receptor is not correlated with a proliferative response to TPO. In summary, extensive studies on normal human and animal cells demonstrated the specificity and function of the MPL receptor and proved that its ligand TPO is the major physiological regulator of megakaryocytopoiesis. The data reviewed here document the wide expression of the MPL receptor on AML cells and also suggest some proliferative effects on certain leukemia cells, apparently on non-megakaryocytic AML cells as well. Thus, experimental evidence supports the notion that TPO may contribute, at least in part, to leukemogenesis, especially in combination with other hematopoietic cytokines which is of clinical significance. TPO-responsive cell lines represent powerful tools for such analyses.
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PMID:Thrombopoietin: expression of its receptor MPL and proliferative effects on leukemic cells. 875 57


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