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[Megakaryocyte polyploidization in acute leukemia and preleukemia].
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Preleukemia: A model for investigation into the etiology and treatment of leukemia.
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A familial disorder characterized by hepatosplenomegaly presenting as "preleukemia".
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[Chromosome studies on blood diseases. I. Chromosome studies on leukemia and preleukemia].
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Diagnostic value of muramidase (Lysozyme) in acute leukemia and preleukemia.
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Chromosome studies in hematological disorders. 3. Chromosome findings in "preleukemia" and related diseases.
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Prelymphomatous or preleukemic state in mice: relation to human preleukemia.
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Chromosome studies in preleukemia. I. Aneuploidy of group C chromosomes in three patients.
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[Preleukemia - analysis of 8 personal cases].
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Chromosome changes (trisomies #15 and 17) associated with tumor progression in leukemias induced by radiation leukemia virus.
An experimental system was developed that permitted nonrandom chromosome changes that occur in radiation leukemia virus (RadLV)-induced lymphomas to be followed during tumor progression. RadLV variant-induced preleukemia and leukemia cells originating from female inbred C57BL/6 mice were injected into male animals of the same strain. Since all donors were females and all recipients were males, the sex chromosome complements (XX and XY) were used to distinguish the preleukemia and leukemia cells from those of host origin. The G-banding analysis revealed that more than 50% of animals that were inoculated with preleukemia cells and that developed leukemia possessed tumor stem-lines of 41 chromosomes with a tristomy of chromosome #15. In animals inoculated with overt leukemia cells and in which tumor progression occurred, the G-banding an additional trisomy of chromosome #17. The cytogenic data strongly suggested that the trisomy of chromosome #15 was the first specific tumor-associated chromosome change that occurred in the process of conversion of RadLV-induced preleukemia cells to fully autonomous tumor cells.
Preleukemic syndrome in children. Report of four cases and review of literature.
Childhood preleukemia, known as a rare condition, was evaluated in four of the authors' cases and in 24 cases from the literature. The required condition was evolution into overt acute leukemia. The children were 5 months to 15 years of age, and the preleukemia period ranged from 2 to 42 months. The symptoms and physical signs were nonspecific. Different kinds of cytopenia were found in the peripheral blood. Twelve children developed ALL and 16 developed AML. The analysis revealed that in childhood there exist two different types of preleukemia: pre-ALL and pre-AML. The age and sex distribution were different, as were the hematological changes. The marrow was usually hypoplastic in pre-ALL but hyperplastic in pre-AML. True hypoplasia in any of the three cell lines was more common in pre-ALL, whereas ineffective thrombopoiesis and normal or increased myelopoiesis were specific for pre-AML. Ineffective erythropoiesis was characteristic of both types. A typical chromosomal change in marrow, seen in pre-AML only, was a missing group C chromosome. The childhood pre-AML resembled adult preleukemia (also pre-AML) in many aspects, whereas the childhood pre-ALL seemed to be a different entity. It might be assumed that all preleukemic conditions do not evolve to overt malignancy. The incidence and true prognosis therefore remain unknown.
Treatment of preleukemic syndromes with marrow transplantation.
Thirty patients with advanced preleukemic syndromes were treated with marrow transplantation. Most cases were diagnosed by the presence of peripheral pancytopenia and a diagnostic marrow examination but in 6 of the 30 patients pretransplant chromosome studies were instrumental in establishing the diagnosis. Three patients prepared for transplantation with cyclophosphamide alone recurred with their disease within 6 months of transplantation. The other 27 patients were treated with cyclophosphamide and total body irradiation. Twenty of these 27 patients had preleukemia not associated with prior therapy or severe marrow fibrosis. Thirteen of these 20 are alive and well 9 to 56 months from transplant and 7 died, 4 of interstitial pneumonia, 2 of candida septicemia, and 1 of disseminated zoster. There have been no disease recurrences in this group. The remaining preleukemic patients, which include 3 patients transplanted for preleukemia secondary to prior therapy and 4 patients transplanted for preleukemia associated with severe marrow fibrosis, have all died. Major problems in these patients included disease recurrence (2 cases) and, in those with severe marrow fibrosis, graft failure (2 cases). These results suggest that for patients with life-threatening pancytopenia due to spontaneous preleukemia without severe marrow fibrosis, marrow transplantation can prolong disease-free survival and may result in cure of the disease.
Partial myeloperoxidase deficiency.
Neutrophil myeloperoxidase (MPO) activity was analyzed by a semi-quantitative cytochemical method in 268 subjects divided into several groups. 17 subjects with significantly reduced MPO activity were found: 11 of 23 in the preleukemia group, 2/14 AMLs, 1/20 myeloproliferative syndrome, 1/7 carcinoma with bone marrow metastases, 1/33 diabetes mellitus and 1/50 normals. Only in the preleukemia group, was MPO significantly reduced in comparison to the normal group (p less than 0.005). The high frequency of acquired MPO deficiency in preleukemia represents a useful criterium for this diagnosis. Furthermore, in these patients, as well as in the other subjects studied, no apparent correlation between MPO level and infection could be demonstrated.
Protein kinase C mediates mutant N-Ras-induced developmental abnormalities in normal human erythroid cells.
RAS mutations are one of the most frequent molecular abnormalities associated with myeloid leukemia and preleukemia, yet there is a poor understanding of how they contribute to the pathogenesis of these conditions. Here, we describe the consequences of ectopic mutant N-Ras (N-Ras*) expression on normal human erythropoiesis. We show that during early (erythropoietin [EPO]-independent) erythropoiesis, N-Ras* promoted the amplification of a phenotypically primitive but functionally defective subpopulation of CD34(+) erythroblasts. N-Ras* also up-regulated the expression of megakaryocyte antigens on human erythroblasts. Although early erythroblasts expressing N-Ras* were able to respond to erythropoietin and generate mature progeny, this occurred with greatly reduced efficiency, probably explaining the poor colony growth characteristics of these cells. We further report that this oncogene promoted the expression and activation of protein kinase C (PKC) and that the effects of N-Ras* on erythropoiesis could be abrogated or attenuated by inhibition of PKC. Similarly, the effects of this oncogene could be partially mimicked by treatment with PKC agonist. Together, these data suggest that expression of N-Ras* is able to subvert the normal developmental cues that regulate erythropoiesis by activating PKC. This gives rise to phenotypic and functional abnormalities commonly observed in preleukemia, suggesting a direct link between RAS mutations and the pathogenesis of preleukemia.
Efficacy of intensive chemotherapy for acute myelogenous leukemia associated with a preleukemic syndrome.
One hundred ninety-six patients with acute myelogenous leukemia (AML) were treated with intensive induction chemotherapy using similar daunorubicin/cytarabine/thioguanine regimens. Treatment results of 44 patients who had a documented preleukemic syndrome or cytopenia present for more than 2 months before developing over AML were compared with 152 patients with de novo AML. Eighteen (41%) patients with preleukemia evolving into AML achieved complete remission compared with 111 (73%) patients with de novo AML (P less than .01). Patients with preleukemia-AML had a significantly longer period to recovery of granulocytes. Multivariate analysis indicated that presence of a previous preleukemic syndrome and advancing age were independent poor prognostic indicators for achieving remission. For patients who achieved remission, disease-free survival and overall survival were also inferior for patients with previous preleukemia; disease-free survival was 17 +/- 17% at 3 years compared with 29 +/- 10% in patients with de novo AML (P = .02). These data indicate that intensive chemotherapy has limited efficacy in patients with AML following a preleukemic syndrome. Durable remissions may be achieved in some patients.
[Role of chromosome aberrations in the development of leukemic process].
The pathogenetic and clinical significance of karyotype features in leukemia and preleukemia are analysed. In 34.7 per cent patients with preleukemia, karyotype instability was observed which consisted in numerical and structural chromosome aberrations with clone anomaly. It was found that karyotype instability is an initial stage of anomalous clone formation and often precedes its development in preleukemia, secondary leukemias, and in preblastic stage of chronic myeloid leukemia. Acute leukemias were found to be characterized by premeditated numerical and structural chromosomal aberrations with predominant involvement of chromosomes 5, 7, 8, and 21 in non-lymphoblastic and chromosomes 6, 9, 8, and 21 in lymphoblastic forms of acute leukemia. It was also shown that the normal to abnormal metaphase ratio in acute leukemia patients is of high prognostic value.
1,25-Dihydroxyvitamin D3: in vivo and in vitro effects on human preleukemic and leukemic cells.
The active metabolite of vitamin D known as 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] is a major physiologic regulator of mineral metabolism in man. The compound is also a potent inducer of differentiation of a human promyelocytic leukemia cell line known as HL-60. The induction of differentiation of myeloid leukemia cells to functional end cells offers an appealing therapeutic prospect. We investigated the ability of 1,25(OH)2D3 both to induce in vitro the differentiation of blast cells taken from patients with acute myelogenous leukemia and to improve hematopoiesis in vivo in patients with the myelodysplastic syndromes (preleukemia). We found that high concentrations (10-6 M) of 1,25(OH)2D3 significantly induced the in vitro differentiation of blast cells as measured by morphology, phagocytosis, and superoxide production. A concentration of 10-9 M 1,25(OH)2D3 had no effect on blast cell differentiation. We gave 2 microgram/day of 1,25(OH)2D3 to 18 patients with myelodysplastic syndrome (preleukemia) in an attempt to improve their hematopoiesis. During therapy, their peak peripheral blood granulocyte, platelet, and macrophage concentrations were slightly elevated as compared to their baseline, starting levels. Eight patients had a partial or minor peripheral blood response to the compound during the administration of 1,25(OH)2D3. However, no patient showed significant improvement of peripheral blood cell or marrow blast cell counts by the end of the study (greater than or equal to 12 weeks) as compared to their starting levels. Seven of the patients developed leukemia before or by 12 weeks of treatment. Nine of the 18 patients developed hypercalcemia. Taken together, the study shows that high concentrations (10-6M) of 1,25(OH)2D3 can induce differentiation of leukemia blast cells in vitro, but the administration of 1,25(OH)2D3 to patients with the myelodysplastic syndromes (preleukemia) does not have an enduring therapeutic effect. Hypercalcemia prevented administering greater amounts of 1,25(OH)2D3. In the future, the use of new vitamin D analogs that induce hematopoietic cell differentiation without inducing hypercalcemia might allow the achievement of higher blood levels of the inducing compound and might be medically useful for selected preleukemic and leukemic patients.