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Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

From 583 cases of acute lymphoblastic leukemia (ALL) and 181 cases of acute myeloid leukemia (AML) in childhood, seven patients were identified to have t(11;19) (q23;p13) by sequential cytogenetic analyses. The t(11;19) was associated with B-precursor ALL at diagnosis in three patients and at relapse in one patient. All four tested patients with B-precursor failed to express the CD10 antigen when the t(11;19) was detected, and one of three patients tested expressed myeloid-associated markers. In three other patients the translocation was detected either at lineage conversion from ALL to M5 AML (n = 2) or from AML to CD10- B-precursor ALL (n = 1). Leukemic blasts of four patients had an entirely different karyotype at the time of lineage conversion or loss of CD10 expression, suggesting an induction of a second neoplasm. Thus the t(11;19) can be found in de novo or secondary acute leukemia with lymphoid (CD10-) or myeloid (monoblastic) phenotype. Further investigation of the gene(s) involved in the 11q23 chromosomal region and the breakpoints in the 19p13 region is needed to understand the leukemogenesis of this apparently heterogeneous group of disorders.
Leukemia 1991 Dec
PMID:Childhood acute leukemia with t(11;19) (q23;p13). 177 55

We have previously shown that all-trans retinoic acid therapy is an alternative therapy for acute promyelocytic leukemia (AML3) via differentiation of the leukemic cells. The t(15;17) translocation is specifically found in this leukemia. We and others have shown that through this translocation the RAR alpha gene is rearranged and its expression altered in AML3 cells. The gene is truncated and fused to a novel gene (PLM). This results in a fusion protein whose transactivating properties may be implicated in the leukemogenesis of this disease. Retinoic acid cytoplasmic binding proteins (CRABP and CRBP) are not detected by PAGE chromatography in normal or malignant hematopoietic cells. During all-trans RA therapy, a) all-trans RA plasma concentrations are within in vitro differentiating concentration (med. 0.4 microgram/ml); b) increased expression of the normal remaining RAR alpha allele is rapidly observed and may explain the paradoxical induction of RA differentiation in these cells; c) CRABPII is induced in the bone marrow cells of AML3 patients and remains detectable 1 month after withdrawal of RA. AML3 in relapse after RA therapy is always less sensitive to RA in vitro and in vivo. Our data suggest that modification of the metabolisation pathways of RA may be one of parameters linked to this resistance. It appears that the efficacy of all-trans RA is the resultant of multiple parameters (RA concentration, ratio of PML/RAR alpha transcripts to normal RAR alpha, CRABP) which need to be defined to efficiently monitor all-trans RA therapy in APL.
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PMID:[Biological parameters of the efficiency of retinoic acid in acute leukemia]. 182 94

The Friend or Moloney mink cell focus-forming (MCF) virus encodes a recombinant-type envelope glycoprotein, gp70, that is closely related to the membrane glycoprotein, gp55, of Friend spleen focus-forming virus (SFFV). We have shown previously that gp55 has the ability to activate cell growth by binding to the cellular receptor for erythropoietin. Here we show that gp70 encoded by either the Friend or Moloney MCF virus also binds to the erythropoietin receptor and that coexpression of the receptor and gp70 in an interleukin-3 (IL-3)-dependent cell line can activate IL-3-independent growth. Furthermore, when the cDNA for the human IL-2 receptor beta chain, which is related by sequence to the erythropoietin receptor, was introduced into this cell line, it became growth factor independent after infection either with SFFV or with one of the two MCF viruses but not with an ecotropic virus. Based on these observations, we propose a mechanism for the early stage of leukemogenesis induced by the MCF-type murine leukemia viruses.
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PMID:Mechanism of leukemogenesis induced by mink cell focus-forming murine leukemia viruses. 185 20

The presence of activated transforming genes was investigated in four patients with therapy-related leukemia and in three with therapy-related myelodysplastic syndrome. DNA of bone marrow cells from six of the patients exhibited transforming activity in the tumorigenicity assay. Five of the six patients who were positive in the tumorigenicity assay contained activated N-ras oncogenes, and three contained activated K-ras oncogenes. Thus, concurrent activation of N-ras and K-ras oncogenes was observed in two patients. In vitro DNA amplification followed by oligonucleotide dot-blot analysis was used to investigate mutations in codons 12, 13, and 61 of the N-ras and K-ras oncogenes. Two patients exhibited an N-ras mutation, substituting aspartic acid (GAT) for glycine (GGT), and three patients exhibited an N-ras codon 13 mutation, substituting valine (GTT) for glycine. Two patients exhibited K-ras codon 12 mutations, substituting aspartic acid (GAT) or cysteine (TGT) for glycine (GGT), respectively, and one case exhibited a K-ras codon 61 mutation, substituting lysine (AAA) for glutamic acid (CAA). Cytogenetic analysis revealed that loss of chromosome 7 was frequent (four patients: 57%). Our data indicate that activation of N-ras and K-ras genes, as well as loss of heterozygosity for specific alleles on chromosome 7, plays a more important role in the leukemogenesis of both therapy-related leukemia and myelodysplastic syndrome.
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PMID:Transforming genes and chromosome aberrations in therapy-related leukemia and myelodysplastic syndrome. 185 83

A continuous cell line was established from the blood of a patient (HH) with an aggressive cutaneous T-cell leukemia/lymphoma who lacked antibodies to human T lymphotrophic virus, type I. The immunophenotype of the cultured cells was CD2+, CD3+, CD4+, CD5+, CD8-, DR+ and CD25- (Tac, IL-2 receptor alpha chain). Southern-blot hybridization analysis of T-cell-receptor beta chain DNA demonstrated the same rearrangement in freshly isolated blood cells and cultured cells, indicating that the cell line was derived from the patient's malignant clone. Since cultured T-cells grew in complete medium without added IL-2, we investigated whether HH cells could be producing and responding to IL-2 in an autocrine fashion. However, no IL-2 was detectable in supernatant from the cell line, while antibodies to IL-2, or to the IL-2 receptor alpha or beta chains did not inhibit cell growth. In addition, no mRNA message for IL-2 was detectable in these cells. The results appear to exclude an autocrine IL-2-dependent mechanism of cell growth for this T-cell line. Although cultured HH cells lacked detectable IL-2 receptor alpha chain, they did show increased proliferation to exogenous IL-2. Binding studies with 125I-IL-2 demonstrated an intermediate affinity receptor for IL-2, KD = 1.7 nM, with 6400 binding sites per cell, suggesting the presence of an IL-2 receptor beta chain. Consistent with these findings 125I-IL-2 cross-linking studies demonstrated a single receptor calculated to be 75 kDa. Also, the beta chain of the IL-2 receptor was detected by immunofluorescence using specific monoclonal antibodies (MAbs). Nanomolar concentrations of an IL-2-diphtheria toxin fusion protein inhibited cellular protein synthesis, an effect abrogated by native IL-2. These findings indicate that the IL-2 receptor beta-chain was functional. This novel mature T-cell line may be useful in studies of IL-2 receptor regulation and in analysis of the mechanism of T-cell leukemogenesis.
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PMID:Establishment of an IL-2 independent, human T-cell line possessing only the p70 IL-2 receptor. 187 69

To investigate the possible role of the product of the retinoblastoma susceptibility gene, pRB, in leukemogenesis, we examined fresh leukemia cells from 56 cases of primary leukemia (AML, 32; ALL, 12; CML-BC, 9; CLL, 3) for expression of pRB by using an immunoblotting assay with anti-pRB monoclonal antibodies PMG 3-245 or 3-340. Expression of the 70 kDa heat shock protein (Hsp70) was examined simultaneously as an internal control. pRB was found to be absent or expressed at an abnormally low level in 13 of 56 cases. Abnormal expression of pRB was most common in AML (8/32) and CML-BC (4/9), and less common in ALL (1/12). Expression of pRB was not induced in two cases of pRB- AML cultured for 24 h with GM-CSF, indicating that pRB expression could not be induced by increasing the rate of proliferation. The eight cases of AML lacking pRB protein were examined for RB1 mRNA by Northern blot. Two lacked RB1 mRNA and six had a normal-sized mRNA (approximately 4.7 kb), although the amount of RB mRNA was very low in some cases. RB1 gene structure was normal by Southern blot in all eight cases lacking pRB protein which were studied. These results show that lack of pRB expression is relatively common in human myeloid leukemias, and suggests that loss of pRB expression could contribute to the altered growth control of these cells.
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PMID:Heterogeneous expression of the product of the retinoblastoma susceptibility gene in primary human leukemia cells. 188 10

A leukemia line KOPN30bi was established from a patient of acute lymphoblastic leukemia with Philadelphia chromosome. The clonal rearrangement of the immunoglobulin heavy chain gene was identical between KOPN30bi and the predominant clone in the fresh sample (S1) from which KOPN30bi was established, indicating that they are of the same clonal origin. The study of the T cell receptor (TCR) genes including TCR beta, gamma, delta loci showed none of these loci was identical between KOPN30bi and S1. The result of the TCR delta region analysis which was rearranged on one of the alleles in KOPN30bi and was deleted on both alleles in S1, however, indicated KOPN30bi was not a derivative of S1. Polymerase chain reaction, using oligonucleotide probe corresponding to the N region sequence of V gamma-J gamma juncture of KOPN30bi, indicated that only one % of the blast cells in S1 corresponded to KOPN30bi. These studies indicated that the predominant clone in the fresh sample, although it occupied more than 99% of the blasts, did not represent the characteristics of the target cell for leukemogenesis, and furthermore that the leukemogenic molecular mechanisms such as P190 type BCR/ABL translocation are not enough to freeze the differentiation of the target cell.
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PMID:[Antigen receptor gene analysis in lymphoid malignancies--a study using the polymerase chain reaction]. 189 Jul 40

The analysis of the configuration of the immunoglobulin (Ig) and T-cell receptor (TCR) gene regions has been of great relevance in defining conclusively the nature of several lymphoproliferative disorders in man. Furthermore, this technological tool has also helped to dissect between a monoclonal and polyclonal pattern of proliferation. The major results obtained, the potential use of molecular studies for the detection of minimal residual disease and the relevance of these techniques in the understanding of the processes of leukemogenesis and lymphomagenesis are discussed.
Leukemia 1991
PMID:Immunoglobulin and T-cell receptor gene analysis in lymphoproliferative disorders. 189 Aug 61

Human T-cell leukemia virus type I (HTLV-I) is the etiologic agent of adult T-cell leukemia, and the clonally derived leukemic cells all contain proviral genomes. Polymerase chain reaction with a variety of primers which span the HTLV-I genome was used to determine that a significant fraction of patients (at least 32%) carry deleted viral genomes in their leukemic cells. The pX region of the HTLV-I genome encoding the regulatory genes tax and rex was preferentially retained. The fact that the tax coding region was retained provides supporting evidence that the tax protein contributes to leukemogenesis in vivo. The reasonably high fraction of patients with adult T-cell leukemia carrying deleted genomes in their tumor cells suggests that the deletions have a role in leukemogenesis.
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PMID:Polymerase chain reaction analysis of defective human T-cell leukemia virus type I proviral genomes in leukemic cells of patients with adult T-cell leukemia. 189 96

N-ras gene activation occurs via single base substitutions in codons 12, 13, and 61. We have developed a rapid screening method, termed allele specific restriction analysis (ASRA), for detection of N-ras mutations at these three critical codons in acute myeloid leukemia (AML). Patient DNA samples are amplified by the polymerase chain reaction (PCR) by using primers that induce restriction sites in normal but not mutant N-ras alleles. We have used ASRA to identify 5 point mutations in four out of 19 patients at initial presentation of de novo AML. Three patients had one mutation at codon 12, 13, or 61 respectively, while a fourth patient had concurrent mutations at codons 12 and 13. N-ras mutations were more common in patients over 65 years of age (P less than 0.04), but did not correlate with FAB classification, attainment of complete remission, disease free survival, or overall survival. ASRA can also be used as the first step in a more sensitive approach to the detection of ras mutations. When ASRA was combined with allele specific oligonucleotide (ASO) hybridization the sensitivity and specificity of these assays were increased. This allowed identification of additional low level mutations in two patients. The data presented here constitute the first complete analysis of N-ras mutations in leukemia by ASRA and include the first identification of three concurrent N-ras mutations in a single leukemic patient. By facilitating sensitive sequential studies, ASRA should contribute to our understanding of the role of N-ras mutations in leukemogenesis.
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PMID:Analysis of N-ras gene mutations in acute myeloid leukemia by allele specific restriction analysis. 195 19


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