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

We report on eight patients who were 35 to 77 years old with an isochromosome 17q as the sole structural chromosomal anomaly. Additional numerical chromosomal changes were a trisomy 8 or 17 in two cases each and a trisomy 19 in one case. Five patients had myelodysplastic syndrome (MDS) diagnosed according to the FAB nomenclature as chronic myelomonocytic leukemia (CMML) in two cases, refractory anemia with excess of blasts in transformation (RAEBt) in two cases, and refractory anemia with excess of blasts (RAEB) in one case. One patient suffered from a myeloproliferative disorder (MPS). All cases progressed to acute nonlymphocytic leukemia (ANLL) type M1, M2, or M4 in a period of 2 to 30 months after initial diagnosis, except one patient with RAEBt who died within 2 months. Two patients presented with ANLL-M2 at time of diagnosis. Treatment during the chronic phase of disease consisted of mild cytoreduction and/or substitution of platelets or red blood cells. One patient with CMML received an allogeneic bone marrow graft and relapsed after 33 months with ANLL-M1. Treatment results for overt leukemia were poor, and survival was short, lasting from 1 to 4 months. Overall survival was 1 to 37 months (median duration, 6.5 months). Molecular studies in two cases revealed neither a BCR rearrangement nor a translocation of the ABL protooncogene, as observed in Ph1-positive chronic myeloid leukemia (CML). Thus, an i(17q) anomaly seems to identify a distinct subgroup of mostly myelodysplastic and, less frequently, myeloproliferative disorders that progress rapidly to ANLL, respond poorly to chemotherapy, and are associated with short survival after transformation.
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PMID:Isochromosome 17q in Ph1-negative leukemia: a clinical, cytogenetic, and molecular study. 222 38

A patient who was diagnosed with chronic myeloid leukemia remained in chronic phase for 14 years before progressing into a lymphoid blast crisis in 1983. The acute phase was successfully treated, and the patient has remained in an indolent chronic phase to date. Cytogenetic and molecular analysis during this second chronic phase confirm the presence of the Philadelphia chromosome and its transcribed BCR-ABL mRNA. The breakpoint within M-bcr occurred in the 3' portion of the region and expressed a hybrid joining the b3 exon of BCR to the a2 exon of ABL.
Leukemia 1990 Jun
PMID:Molecular analysis of a CML patient with a long duration of chronic phase before and after lymphoid blast crisis. 235 47

Cellular or proto-oncogenes are normal cellular genes important in normal cell growth and development. In some instances abnormal expression of these genes is associated with altered cell growth or with malignant transformation. Abnormalities of cellular oncogenes are common in human leukemias. These arise by multiple mechanisms such as mutation, translocation, amplification, and others. Sometimes more than one abnormality is present within a single oncogene. In other instances, a leukemia cell may contain abnormalities of several different oncogenes. Some oncogene abnormalities are relatively specific for certain leukemias and occur in almost all cases; examples include ABL in chronic myelogenous leukemia or MYC in Burkitt leukemia/lymphoma. Other abnormalities are also relatively specific but occur in only some cases such as NRAS in acute myelogenous leukemia or BCL2 in B-cell acute lymphoblastic leukemia. In other leukemias, such as most cases of acute lymphoblastic leukemia and chronic lymphocytic leukemia, oncogene abnormalities are uncommon. The precise role of oncogenes in the pathogenesis of human leukemia is unknown. Retrovirus transduced versions of some of the oncogenes modified in human leukemias cause leukemia in animals. Other oncogenes, modified or unmodified, transform animal and human hematopoietic cells in vitro. Some oncogene products are hematopoietic growth factors or growth factor receptors while others regulate cell proliferation or differentiation by diverse mechanisms. Disruption of the balance between these processes seems the most likely mechanism of oncogene related leukemogenesis. If the role of oncogenes in human leukemias can be defined, innovative diagnostic and therapeutic strategies may be forthcoming.
Leukemia 1990 Feb
PMID:Oncogenes and leukemia. 240 17

The great majority of patients with chronic myeloid leukaemia (CML) have a Philadelphia (Ph) chromosome which has proved at molecular level to be associated with the production of chimeric BCR-ABL gene which in turn is expressed as a fusion protein (P210) with tyrosine kinase activity. An equivalent but somewhat smaller chimeric gene and fusion protein (P190) is found in some cases of Ph-positive acute leukaemia. Though the consistency of these abnormal findings in patients with Ph-positive leukaemia is strong evidence for their pathogenetic role, there are still many unanswered questions.
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PMID:Recent advances in molecular biology of chronic myeloid leukaemia: is the pathogenetic puzzle approaching solution? 249 82

Two patients with acute nonlymphocytic leukemia (ANLL) who had normal karyotypes at diagnosis and developed the Philadelphia (Ph) translocation during leukemia relapse are described in this report. Patient 1 relapsed with Ph-positive acute leukemia, FAB classification M1. The Ig heavy chain locus and T cell receptor gamma and beta genes of relapse cells from this patient were all found to be germline configuration confirming the diagnosis of M1 acute leukemia. Patient 2 displayed a complex karyotypic evolution leading to Ph-positive M4 relapse. Ph-positive relapse specimens from both patients expressed P185BCR-ABL protein and RNA gene products that were identified serologically and by polymerase chain amplification of the BCR-ABL RNA junction. In vitro derived myeloid cell lines from relapse M1 leukemia cells of patient 1 also expressed the P185BCR-ABL protein. In two described patients, late appearance of the Ph translocation that encodes P185BCR-ABL coincided with relapse of acute leukemia. We conclude that P185BCR-ABL may be a strong indicator of Ph-positive acute leukemias.
Leukemia 1989 Dec
PMID:P185BCR-ABL in two patients with late appearing Philadelphia chromosome-positive acute nonlymphocytic leukemia. 268 76

A patient whose leukaemic cells carried the rare t(7;11)(p15;p15) was diagnosed as having acute myelomonocytic leukaemia (AML-M4), and supports the association of this specific translocation with forms of acute myeloid leukaemia showing differentiation. Blast phase chronic myeloid leukaemia was excluded by lack of involvement of the ABL and BCR genes. Chromosome in situ hybridization studies showed that both the HRAS1 and INS genes were present on the terminal part of chromosome 11p which was translocated to chromosome 7p. Neither HRAS1 nor INS were structurally rearranged. Field inversion gel electrophoresis showed that a 400 kb fragment encompassing HRAS1 was structurally entire in leukaemic DNA. Because the INS gene, which was also translocated, is probably located proximal to HRAS1 on chromosome 11p, it is unlikely that HRAS1 was near the chromosome 11 breakpoint or involved in this leukaemia.
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PMID:HRAS1 and INS genes are relocated but not structurally altered as a result of the t(7;11)(p15;p15) in a clone from a patient with acute myeloid leukaemia (M4). 271 71

The Philadelphia (Ph) chromosome usually results from the t(9;22), which causes the physical association of the BCR1 and ABL genes and their function as a single new gene. This precise genomic mutation probably has a significant role in the development of leukemia in humans, but that leukemia may take several forms: chronic myeloid leukemia (CML), acute myeloid leukemia, acute lymphocytic leukemia, and essential thrombocythemia; CML also transforms to a lymphoid or myeloid acute phase. Two models are considered with regard to determinants of this variable hematologic expression of BCR-ABL. The first is variation in the breakpoint site of BCR1. Two breakpoint sites, M-BCR and m-BCR, are known, and their occurrence shows a nonrandom association with the different forms of leukemia. The precise position of the breakpoint within M-BCR may also be important. The second model concerns the role of other genes in determining the leukemic form shown by BCR-ABL. Results are reviewed of a patient who entered blast crisis CML and whose leukemic clones involved ten genetic loci with known leukemic associations. Many of these were probably genetic variants that allowed leukemic proliferations following the initiation of blast crisis. The multiplicity of these genes may obscure the prime determinant of blast crisis, which is unknown at the present time.
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PMID:The variable hematologic expression of the BCR-ABL genomic mutation and its possible determinants. 279 Jul 50

The long terminal repeat (LTR) of the pre-B cell tropic Abelson murine leukemia virus (A-MuLV) was replaced with the LTR of the erythrotropic Friend MuLV or with the LTR of the erythropic/fibrotropic Harvey murine sarcoma virus (Ha-MuSV) to generate the viruses F-ABL and H-ABL, respectively. The parental A-MuLV and the recombinant viruses induced pre-B cell lymphomas in susceptible mice with similar frequencies. Recombinant virus-induced tumor DNAs were analysed by nucleic acid hybridization and were shown to contain the appropriate recombinant provirus. F-ABL was 100-1000 fold less efficient than A-MuLV or H-ABL in the in vitro transformation of primary bone marrow cells, as detected by lymphoid colony formation in agarose. To compare the level of transcription initiated from the different viral LTRs, we investigated the ability of the U3 region of these retroviral LTRs to promote transcription in a battery of cell lines using the chloramphenicol acetyl-transferase (CAT) assay, and with some exceptions we found the following hierarchy of activities: Ha-MusSV greater than or equal to M-MuLV greater than A-MuLV greater than F-MuLV, regardless of the cell line transfected. These results indicate that the LTR is not a determinant of the pre-B cell disease specificity of A-MuLV, and suggest that this specificity resides in the v-abl oncogene. Also, our results suggest that a threshold amount of the v-abl protein product is necessary for in vitro transformation, and this level of expression may be different from the level selected during in vivo tumorigenesis.
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PMID:Substitution of the LTR of Abelson murine leukemia virus does not alter the cell type of virally induced tumors. 283 88

Breakpoints on chromosome 22 in the translocation t(9;22) found in Philadelphia positive acute lymphoblastic leukaemia patients fall within two categories. In the first the breakpoint is localized within the breakpoint cluster region of the BCR gene, analogous to the chromosome 22 breakpoint in chronic myeloid leukaemia. The second category has a breakpoint 5' of this area, but still within the BCR gene. We have previously shown that these breakpoints occur within the first intron of the BCR gene and cloned the 9q+ junction from such a patient. We have now determined the sequences around the breakpoints on both translocation partners from this patient as well as the germline regions. The chromosome 9 ABL sequence around the breakpoint shows homology to the consensus Alu sequence whereas the chromosome 22 BCR sequence does not. At the junction there is a 6 bp duplication of the chromosome 22 sequence which is present both in the 9q+ and in the 22q- translocation products. Possible mechanisms for the generation of the translocation are discussed.
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PMID:Nucleotide sequence of both reciprocal translocation junction regions in a patient with Ph positive acute lymphoblastic leukaemia, with a breakpoint within the first intron of the BCR gene. 291 61

A translocation between chromosomes 7 and 9, t(7;9), has been described in cell lines derived from the malignant cells of children with acute T-cell lymphoblastic leukemia or lymphoma. Our cytogenetic analysis of one such cell line, SUP-T3, demonstrates that the breakpoints on chromosomes 7 and 9 lie within bands q36 and q34, respectively, corresponding to the location of the gene encoding the beta chain of the T-cell receptor, TCRB, and the gene homologous to the transforming gene of the Abelson murine leukemia virus, ABL. We investigated the role of these genes in the t(7;9). In situ chromosomal hybridization of TCRB and ABL probes to metaphase cells from SUP-T3 demonstrated that ABL is translocated from chromosome 9 to 7 and that all or part of TCRB is translocated from chromosome 7 to 9. Southern blot analysis revealed that both TCRB alleles were rearranged; however, it could not be determined whether the translocation breakpoint lies within this gene. Pulsed-field gel electrophoresis and Southern blot analysis were used to examine more than 500 kilobases of the ABL locus; we concluded that there are no rearrangements within 250 kb in either direction of the sequences homologous to v-abl. Additionally, no abnormal ABL protein was detected in an in vitro phosphorylation assay. These results indicate that, in SUP-T3, the breakpoint on chromosome 9 lies proximal to ABL and that the break results in no apparent alteration of the ABL protein. We therefore hypothesize that another gene on chromosome 9, at band q34, plays a role in this translocation. This study also demonstrates that pulsed-field gel electrophoresis is a powerful new tool for the analysis of human chromosomal translocations.
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PMID:Molecular analysis of TCRB and ABL in a t(7;9)-containing cell line (SUP-T3) from a human T-cell leukemia. 302 59


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