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

Myelodysplastic syndrome (MDS) in childhood is considered to be very rare, but sound epidemiologic data are lacking. We report a population-based study of MDS in Denmark from 1980 to 1991. The medical charts were reviewed of 988 children identified from the Danish National Hospital Discharge Registry with a diagnosis of myeloid leukemia or blood cytopenia. Blood and bone marrow smears from all cases of possible MDS were re-evaluated. The cases were categorized according to the FAB classification, with the exception of chronic myelomonocytic leukemia (CMML) in which more than 5% myeloblasts in the blood was accepted. Juvenile chronic myeloid leukemia (JCML) was included as CMML. MDS was diagnosed in 46 children representing 9% of all hematologic malignancies in children less than 15 years of age. The annual incidence was 4.0/million and did not increase with time. Refractory anemia with excess of blasts and CMML each accounted for one third of the cases. Down syndrome was present in seven children. Other predisposing conditions included Fanconi anemia, neurofibromatosis, constitutional trisomy 8 mosaicism, and familial leukemia. Only one child had therapy-related MDS. The study indicates that the incidence of childhood MDS is higher than generally assumed and approximate to the incidence of acute myeloid leukemia.
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PMID:Childhood myelodysplastic syndrome in Denmark: incidence and predisposing conditions. 765 25

Clonal analysis of FACS-purified primitive hematopoietic stem cells and of their progeny as assessed by the progenitors obtained from long-term cultures requires PCR-based approaches, mainly because of the low number of cells available. We have developed a non-radioactive androgen receptor (AR) assay which allows a simple and quantitative evaluation of the clonality of hematopoietic cells and progenitors. In this approach 5' AR primer is labelled by fluorescein and the amplified product is run on a sequencing gel which allows evaluation of the intensity of the fluorescent peaks generated. A computer software then analyzes the reduction of the intensity of the peaks on HpaII-digested samples. In order to determine the feasibility of the technique, we analyzed the clonality of leukemic cells from a patient with an acute-phase CMML which showed a typical clonal pattern of her leukemic DNA sample (WBC = 300 x 10(9)/I) using phosphoglycerate kinase (PGK) analysis. The same sample was then analyzed with either radioactive- or fluorescein-labelled AR primers, showing a typical clonal pattern (complete disappearance of one allele after HpaII digestion). A short-term clonogenic assay was then set up on methylcellulose and clonogenic progenitors were individually analyzed. All 24 colonies tested showed a typical clonal pattern with the disappearance of the same allele on each sample after HpaII digestion, indicating that they all derived from the same leukemic stem cell. Using this approach we then analyzed 94 patients with several hematologic malignancies and quantification of their fluorescent peaks. Fifty-four percent of the patients were clearly heterozygous (ie, a difference of > or = 2 CAG repeats was present between the two copies of the gene) and could be analyzed in an automatic sequencer using the fluorescent primers. Bone marrow mononuclear cells from all patients with acute myeloid leukemia (AML) showed a clonal or oligoclonal pattern at diagnosis whereas a polyclonal pattern was seen when remission was obtained. Similarly, out of 21 patients with a diagnosis of myelodysplastic syndrome (MDS), a clonal pattern was demonstrated in 10 whereas an oligoclonal or non-clonal pattern was shown in 11. These results show that this non-radioactive and safe technology can now be used on a large scale to evaluate the clonality of highly purified hematopoietic stem cells and their progenitors in hematopoietic malignancies and this might allow new insights into the targets of clonal amplification.
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PMID:Quantitative non-radioactive clonality analysis of human leukemic cells and progenitors using the human androgen receptor (AR) gene. 765 27

Clonality assays may provide an additional and helpful approach to understanding the problem of the single or multistep pathogenesis of hematologic malignancies. In the absence of specific cytogenetic and/or molecular abnormalities, the study of X chromosome inactivation pattern in female patients represents a useful indirect approach for determination of the clonal or polyclonal nature of a cell population of unknown origin or the persistence of clonal hemopoiesis in leukemia after treatment. An intriguing observation was the documentation of an apparent clonal hematopoiesis in a quite high proportion of AML patients during morphological remission. These data were interpreted as evidence of a multi-step origin of AML, in which a first 'hit' was responsible for the growth advantage of a cytogenetically silent and morphologically normal preleukemic clone, whereas a second 'hit' would give rise to the overt leukemic phenotype. More recent surveys on the frequency of clonal remission, however, arrived at discordant results and could detect the occurrence of true clonal remission in a much lower percentage of cases than previously reported. These apparent discrepancies, which in part may be explained by differences in the series studied and in the approach used to detect clonality, for the moment leave open the fascinating issue of the single or multistep origin in many human leukemias.
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PMID:Single or multistep origin of hemopoietic tumors: the contribution of clonality studies. 765 29

Three marrow transplant recipients with hematologic malignancies (two AML, one myelodysplastic syndrome) experienced prolonged pancytopenia after allogeneic BMT following conditioning with non-TBI regimens containing high-dose busulfan and cyclophosphamide (Bu/CY), despite the use of G-CSF. Early recovery of host-derived hematopoiesis ensued. Although neutrophil counts in these patients exceeded 500 x 10(6)/l by day 30 after transplant, these cells were of host origin. This early recovery of host-derived hematopoiesis has been observed rarely among patients conditioned with TBI-based regimens. When patients conditioned with Bu/CY show delayed hematologic recovery, mixed chimerism should be considered even in the presence of normal neutrophil recovery.
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PMID:Early recovery of host-derived hematopoiesis in marrow transplant recipients conditioned with high-dose busulfan and cyclophosphamide. 767 Apr 8

Interleukin-4 (IL-4), originally identified as a B-cell growth factor, has been shown to inhibit certain stages of hematopoietic stem cells. Recently, IL-4 has been recognized as a negative regulatory factor in the growth of hematologic malignancy. In myeloid leukemias, IL-4 can suppress the growth of growth factor-dependent leukemic blast cells derived from acute myelogenous leukemia (AML). IL-4 also suppresses the growth of chronic myelomonocytic leukemia cells through inhibiting the "autocrine" production of IL-6 or granulocyte/macrophage colony-stimulating factor. In lymphoid malignancies, IL-4 can inhibit the proliferation of neoplastic cells from Ph1-positive acute lymphoblastic leukemia, non-Hodgkin's B-cell lymphoma, and multiple myeloma. Thus, IL-4 is expected to be useful as a therapeutic agent for these hematologic malignancies.
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PMID:The role of interleukin-4 in the negative regulation of leukemia cell growth. 768 64

Telomeres are essential for function and stability of eukaryotic chromosomes. In the absence of telomerase, the enzyme that synthesizes telomeric DNA, telomeres shorten with cell division, a process thought to contribute to cell senescence and the proliferative crisis of transformed cells. We reported telomere stabilization concomitant with detection of telomerase activity in cells immortalized in vitro and in ovarian carcinoma cells, and suggested that telomerase is essential for unlimited cell proliferation. We have now examined the temporal pattern of telomerase expression in selected hematologic malignancies. We found that, unlike other somatic tissues, peripheral, cord blood, and bone marrow leukocytes from normal donors expressed low levels of telomerase activity. In leukocytes from chronic lymphocytic leukemia (CLL) patients, activity was lower than in controls in early disease, and comparable with controls in late disease. Relative to bone marrow, telomerase activity was enhanced in myelodysplastic syndrome (MDS) and more significantly so in acute myeloid leukemia (AML). Regardless of telomerase levels, telomeres shortened with progression of the diseases. Our results suggest that early CLL and MDS cells lack an efficient mechanism of telomere maintenance and that telomerase is activated late in the progression of these cancers, presumably when critical telomere loss generates selective pressure for cell immortality.
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PMID:Telomerase activity in normal leukocytes and in hematologic malignancies. 772 65

Several phase II clinical studies of all-trans-retinoic acid (ATRA) have been conducted in acute promyelocytic leukemia (APL), an uncommon subtype of acute myeloid leukemia (AML). ATRA has been shown to induce complete remission (CR) in 64% to 96% of patients with APL, and with rapid resolution of the coagulopathy, which is a major cause of early morbidity and mortality. Although CRs induced with ATRA alone are usually not sustained and intensive antileukemic consolidation therapy is required to prolong remission, these findings indicate that a new approach of differentiation therapy is effective in treating patients with APL and may potentially be effective in other malignancies. The presence of the PML/retinoic acid receptor-alpha (PML/RAR-alpha) fusion gene, produced as a result of the unique chromosomal translocation in APL, is a marker of sensitivity to ATRA. Aside from the complications of hyperleukocytosis and the retinoic acid syndrome, ATRA therapy is generally well tolerated. An international study (Intergroup 0129), headed by the Eastern Cooperative Oncology Group, is currently under way to determine further the role of ATRA in the treatment of patients with APL. Given its success in APL, studies of ATRA in other hematologic malignancies are also being conducted. A better understanding of how retinoids modulate carcinogenesis will help determine if the results in APL can be realized in other malignancies treated with ATRA or other retinoids.
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PMID:All-trans-retinoic acid in acute promyelocytic leukemia and its potential in other hematologic malignancies. 783 84

The p16 protein is a cyclin inhibitor encoded by a gene located in 9p21, which may have antioncogenic properties, and is inactivated by homozygous p16 gene deletion or, less often, point mutation in several types of solid tumors often associated to cytogenetic evidence of 9p21 deletion. We looked for homozygous deletion and point mutation of the p16 gene in acute lymphoblastic leukemia (ALL), where 9p21 deletion or rearrangement are also nonrandom cytogenetic findings. Other hematologic malignancies including acute myeloid leukemia (AML), myelodysplastic syndromes (MDS), chronic lymphocytic leukemia (CLL), and myeloma were also studied. Homozygous deletion of the p16 gene was seen in 9 of the 63 (14%) ALL analyzed, including 6/39 precursor B-ALL, 3/12 T-ALL, and 0/12 Burkitt's ALL. Three of the 7 ALL with 9p rearrangement (including 3 of the 5 patients where this rearrangement was clearly associated to 9p21 monosomy) had homozygous deletion compared to 5 of the 55 patients with normal 9p (the last patient with homozygous deletion was not successfully karyotyped). Single stranded conformation polymorphism analysis of exons 1 and 2 of the p16 gene was performed in 88 cases of ALL, including the 63 patients analyzed by Southern blot. Twenty-six of the cases had 9p rearrangement, associated to 9p21 monosomy in at least 12 cases. A missense point mutation, at codon 49 (nucleotide 164), was seen in only 1 of the 88 patients. No homozygous deletion and no point mutation of the p16 gene was seen in AML, MDS, CLL, and myeloma. Homozygous deletion of interferon alpha genes (situated close to p16 gene in 9p21) was seen in only 3 of the 9 ALL patients with p16 gene homozygous deletion, and none of the ALL without p16 gene homozygous deletion. Our findings suggest that homozygous deletion of the p16 gene is seen in about 15% of ALL cases, is not restricted to cases with cytogenetically detectable 9p deletion, and could have a pathogenetic role in this malignancy. On the other hand, p16 point mutations are very rare in ALL, and we found no p16 homozygous deletions or mutations in the other hematologic malignancies studied.
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PMID:p16 gene homozygous deletions in acute lymphoblastic leukemia. 783 69

An association between primary mediastinal germ cell tumors and hematologic malignancies has been recognized since 1985. We present a patient with a suprasellar germ cell tumor and an associated leukemia. A 20-year-old black female presented in December 1987 with a 6-month history of headaches and weight loss, confusion, polyuria, and polydipsia. Evaluation revealed hypernatremia, normal neurologic examination except poor recall, and an enhancing inhomogeneous suprasellar mass on cranial computed tomography. Biopsy of the mass diagnosed a dysgerminoma, which was treated with craniospinal radiation. In February 1988, the patient developed pancytopenia, which resolved with discontinuation of cimetidine and phenytoin. She did well until June 1988 when she presented with skin lesions over the trunk and extremities. Skin biopsy revealed a leukemic infiltration. She was admitted with a WBC 1,500/microliter (without blasts), Hb 11.6 g/dl, PLT 210,000 microliter. Bone marrow biopsy revealed hypercellularity with 50% blasts, demonstrating mixed-lineage acute myeloblastic leukemia (myelomonocytic-M4; megakaryoblastic-M7). The patient was induced with a standard Ara-C/daunorubicin regimen. Two weeks postinduction, she became septic and expired. An autopsy demonstrated leukemic involvement of the spleen, liver, bone marrow, and skin, without residual dysgerminoma. This represents the first reported case of suprasellar dysgerminoma associated with a mixed-lineage leukemia not related to chemotherapy.
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PMID:Mixed-lineage acute myeloid leukemia associated with a suprasellar dysgerminoma. 784 66

To increase the cure rate of advanced hematologic malignancies following allogeneic bone marrow transplantation we sequentially evaluated two intensified conditioning regimens. Eleven patients with acute myeloblastic leukemia (AML) beyond the first complete remission or chronic myelogenous leukemia (CML) not in first chronic phase received an association of 13.5 Gy of fractionated total body irradiation (TBI) followed by cyclophosphamide (CY) 120 mg/kg. Following this regimen, the probability of relapse was 47% at 3 years and the non-relapse mortality rate was 27%. Given the acceptable tolerance of this regimen, 13.5 Gy fractionated TBI was associated with intensified chemotherapy consisting of a combination of CY 120 mg/kg, carmustine 300 mg/m2 and etoposide 600 mg/m2 (CBV). This regimen was administered to 22 patients with comparable diseases. Of these patients, 7 received a transplant from a matched unrelated donor and 2 other patients received a second transplant from the original genoidentical donor. For 15 patients with a genoidentical donor, including the 2 second transplant, the 3 year probability of survival, disease-free survival and relapse are 40%, 40% and 14%, respectively. No regimen-related toxic deaths were recorded during the first 100 days. Of 7 patients with matched unrelated donors, 3 died before day 100, one death being directly attributable to the regimen. Early non-fatal regimen-related toxicity consisted mainly in grade II mucositis with no grade III or IV toxicity in recipients of genoidentical marrow. The late deaths were mainly due to chronic GVH-related complications. In conclusion, the association of fractionated 13.5 Gy TBI and CBV carries a high antileukemic activity and an acceptable toxicity.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Total body irradiation and high-dose cyclophosphamide, BCNU and VP-16 (CBV) as a new preparatory regimen for allogeneic bone marrow transplantation in patients with advanced hematologic malignancies. 788 8


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