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

A combination of monosomy 7 and translocation t(9;22) (q34;q11), rarely observed in acute lymphoblastic leukaemia (ALL), is here reported: a peculiarity of this case was that the "breakpoint cluster region" on chromosome 22 was not rearranged, as demonstrated by molecular analysis, and a new c-abl protein (p190) was found, instead of the usual p210 protein usually associated with the Ph chromosome; moreover a rearrangement of c-abl oncogene was found. The clinical course of this patient was, as expected, unfavorable: a few normal metaphases were observed during a short partial remission.
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PMID:Monosomy 7 and Ph-positive acute lymphoblastic leukaemia: cytogenetic and molecular aspects. 348 Apr

We report two cases of acute lymphoblastic leukemia (ALL) with a late-appearing Philadelphia chromosome (Ph1), confirmed by the expression of BCR-ABL mRNA, using the reverse transcriptase/polymerase chain reaction (RT/PCR) technique. The first patient was a 10-year-old boy with precursor B cell type ALL-L1 (FAB classification). At diagnosis, no metaphase cells were found by chromosome analysis and BCR-ABL mRNA was not observed. At the beginning of relapse, which occurred after 7 months of complete remission, a normal karyotype was observed. At the terminal stage, leukemic cells with Ph1 and BCR-ABL mRNA for the P190 variety were observed. The second patient was a 12-year-old boy with immature T cell type ALL-L1. The metaphase cells showed a 9p- chromosome at diagnosis and Ph1 appeared in addition to 9p- at relapse. Hybrid mRNA for the P210 variety was detected only when Ph1 had developed. The blast cells with Ph1 were derived from the original leukemic clone through clonal evolution, since the same clonal rearrangements of IGH or TCRB were detected in leukemic cells obtained both at diagnosis and relapse in both patients. Thus, in both cases, Ph1 was detected only in the course of ALL along with expression of BCR-ABL mRNA. This observation also confirmed that, as in de novo Ph1-positive ALL, both the P190 and P210 varieties of BCR-ABL mRNA are observed in ALL with late-appearing Ph1.
Leukemia 1995 Oct
PMID:A late-appearing Philadelphia chromosome in acute lymphoblastic leukemia confirmed by expression of BCR-ABL mRNA. 756 11

We designed a new semi-quantitative competitor-based PCR assay to assess the amount of p190 BCR-ABL mRNA in patients with Ph-positive ALL. Transcript numbers were compared in 29 paired specimens of blood and marrow collected contemporaneously from 18 patients at differing stages of disease. In general, the numbers of BCR-ABL transcripts detected in marrow in blood were not significantly different (p = 0.1). However, in four samples BCR-ABL transcripts (< 10-1000/micrograms RNA) were detected in the marrow while the blood was negative; the reverse, positive blood and negative marrow, was not seen. In a further three samples the number of BCR-ABL transcripts was more than 10-fold higher in the marrow. We measured the number of ABL transcripts/micrograms RNA in all samples as an internal standard in order to control for variations in sample quality and other parameters. For two out of the four discordant samples in which blood was PCR negative, the number of ABL transcripts/micrograms RNA detected in the marrow was substantially higher than in the blood, suggesting poor quality blood specimens. However, the ratio of BCR-ABL to ABL in marrow and blood was similar for the three discordant samples in which both tissues were PCR positive. We conclude that in general, blood and marrow contain similar BCR-ABL transcript numbers in Ph-positive ALL but some samples are discordant. Marrow is therefore the preferred tissue for residual disease studies. Quantification of ABL mRNA as an internal control is useful in the interpretation of competitive PCR data and may serve as a robust way to standardize results between laboratories.
Leukemia 1995 Feb
PMID:Quantification of residual disease in Philadelphia-positive acute lymphoblastic leukemia: comparison of blood and bone marrow. 786 72

Adult Philadelphia-chromosome-positive acute lymphoblastic leukemia (Ph1-positive ALL) represents about 30% of all adult ALL, and is considered a poor prognosis disease, since complete remission (CR), which can be achieved in 50-70% of cases, is usually short in patients treated with conventional chemotherapy. Presently bone marrow transplantation, performed early in first CR is becoming the treatment of choice, as it has shown to be able to cure some cases. In a ten-year period, at our department, among 108 adult ALL patients, in which cytogenetics was successfully carried out at diagnosis, 24 (22%) resulted Ph1-positive. Molecular biology was performed in 13 out of these 24 patients: 10 patients showed a p210 rearrangement and three p190. All patients have been treated at induction with conventional drugs, with a CR rate of 96%. As post-remission therapy, the first 17 cases (group 1) followed a chemotherapeutic program, like the other adult ALL; while the remaining six patients (group 2) have been enrolled in a pilot study including early BM transplantation. In group 1, the median overall duration of first CR is 7 months; 50% of relapses were recorded within the first 6 months, although in this group five patients exhibited a first CR prolonged more than 30 months. In group 2, among the six patients, three were submitted to allogeneic bone marrow transplantation (BMT), and three to autologous bone marrow transplantation (ABMT). Overall median duration of first CR is 13 months. Three patients relapsed, three are in continuous CR for 11, 31 and 32 months.
Leukemia 1994 Apr
PMID:Adult Philadelphia-chromosome-positive acute lymphoblastic leukemia: experience of treatments during a ten-year period. 815 62

The presence of the BCR/ABL chimeric gene is the hallmark of defined types of human leukemia. To increase our knowledge of the oncogenic processes and to develop a model for this type of leukemia we generated a BCR/ABL (P190) transgenic mouse line. Over 95% of mice of this line die of leukemia or leukemia/lymphoma within 35-200 days of age. Karyotypically visible genetic alterations were absent from the early stages of BCR/ABL generated leukemia. A high frequency of aneuploidy was found in advanced leukemia indicating a primary and pivotal role for BCR/ABL in leukemogenesis. Moreover, the data suggest that BCR/ABL has a destabilizing effect on the regulation of the cell cycle. BCR/ABL expression was also found in tissues other than hematopoietic cells. However, this did not result in the development of solid tumors, strongly suggesting that the oncogenicity of BCR/ABL is limited to the hematopoietic lineage.
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PMID:Ph-positive leukemia: a transgenic mouse model. 825 94

Constitutive activation of BCR-ABL tyrosine kinase fusion protein has been shown to be an essential step in the pathogenesis of Philadelphia chromosome (Ph)-positive leukemias. We studied the tyrosine phosphorylated proteins which might be involved in the signaling pathway p185BCR-ABL using a Ph-positive acute lymphoblastic leukemia cell line. p185BCR-ABL but not p145c-abl was constitutively phosphorylated on tyrosine in this cell line. p21ras GTPase-activating protein (GAP) was physically associated with p185BCR-ABL, but not with p145c-abl, and GAP-associated proteins p62/p190 were found to be tyrosine-phosphorylated. Furthermore, p185BCR-ABL was also physically associated with phospholipase C-gamma 1 (PLC-gamma) and phosphatidylinositol 3'-kinase (P13-kinase). Concomitantly, both PLC-gamma and p85 subunit of P13-kinase are tyrosine-phosphorylated in the cells with p185BCR-ABL. These data suggest that GAP, GAP-associated proteins, PLC-gamma, and P13-kinase may participate in downstream signaling for p185BCR-ABL tyrosine kinase.
Leukemia 1994 Jan
PMID:Potential molecules implicated in downstream signaling pathways of p185BCR-ABL in Ph+ ALL involve GTPase-activating protein, phospholipase C-gamma 1, and phosphatidylinositol 3'-kinase. 828 76

A rapid and simple polymerase chain reaction (PCR) method is described that is capable of identifying any of the BCR-ABL transcripts that have yet been described in chronic myeloid or acute lymphoblastic leukaemia. Randomly primed cDNA is synthesized from leucocyte RNA and amplified in a single reaction containing four oligonucleotide primers (multiplex PCR). Different size products are generated from ela2 (p190) and b3a2 or b2a2 (p210) BCR-ABL transcripts which are readily and unambiguously distinguishable after agarose gel electrophoresis without the need for either nested PCR or hybridization. Chronic myeloid leukaemia cells are readily detectable even when diluted 1 in 1000 with normal blood. Samples which do not have BCR-ABL rearrangements produce a single band derived from the normal BCR gene, and the presence of this band controls for adequate RNA and cDNA preparation. Using this assay we have detected BCR-ABL transcripts in a variety of haematological disorders.
Leukemia 1994 Jan
PMID:An optimized multiplex polymerase chain reaction (PCR) for detection of BCR-ABL fusion mRNAs in haematological disorders. 828 86

Two-thirds of patients with Philadelphia (Ph) chromosome-positive acute lymphoblastic leukaemia (ALL) have a breakpoint in the minor breakpoint cluster region (m-bcr) of the BCR gene, which results in an e1a2 transcript and a P190BCR-ABL fusion protein. This type of genomic rearrangement occurs very rarely in chronic myeloid leukaemia (CML); it has been reported in only four cases. We describe here a fifth case of P190 CML in which the cytomorphological characteristics were intermediate between CML and chronic myelomonocytic leukaemia (CMML). This case, and the four reported previously, had a consistent and significant monocytosis with a low neutrophil/monocyte ratio in the peripheral blood, resembling CMML. On the other hand, they also had a high percentage of circulating immature granulocytes, basophilia and low neutrophil alkaline phosphatase (NAP) score, which are more commonly found in classical CML. Thus, P190 CML may be a specific form of CML, in which the myeloproliferative process includes the monocytic, as well as the granulocytic lineage. Since the molecular defect in CML is thought to involve a pluripotent stem cell, the different effects of P210BCR-ABL and P190BCR-ABL in CML must reflect the somewhat wider spectrum of activity of the P190BCR-ABL. Other patients with atypical CML or CMML who lack a Ph chromosome may also have an m-bcr breakpoint which would not be detected on standard Southern blots, but which would be detectable by polymerase chain reaction amplification of reverse transcribed RNA.
Leukemia 1994 Jan
PMID:P190BCR-ABL chronic myeloid leukaemia: the missing link with chronic myelomonocytic leukaemia? 793 80

The benign phase of chronic myelogenous leukemia (CML) typically is characterized by an overproduction of myeloid cells that eventually progresses to a more acute stage termed blast crisis. This latter stage can exhibit either myeloid or lymphoid blast clones. Our recent results have demonstrated the presence of the P210 BCR-ABL protein in blood cells from benign phase CML patients (Guo et al., Cancer Research 51:3048, 1991). This protein is the product of an 8.5 kb chimeric RNA encoded by fused BCR-ABL genes produced by the formation of the Philadelphia (Ph) chromosome. Using this new assay we have identified a patient with benign-phase CML who produces P190 BCR-ABL, the form of the BCR-ABL protein found in about 50% of cases of acute lymphocytic leukemia (ALL). This patient lacked detectable P210 BCR-ABL protein and did not contain a DNA rearrangement in the major breakpoint cluster region of the BCR gene. Consistent with this result, polymerase chain reaction (PCR) analyses detected a BCR-ABL mRNA with BCR exon 1 fused to ABL exon 2. No BCR-ABL mRNAs with 2'- or 3'-bcr exon to ABL exon 2 fusions were detected in these analyses. Blood cells from this patient lost P190 BCR-ABL after the patient underwent an allogeneic bone marrow transplant, but regained this protein although the patient was still in chronic phase after a subsequent autologous transplant as treatment for graft failure. These findings indicate that P190 BCR-ABL alone is not sufficient to induce a blast crisis phenotype in leukemia patients who are Ph chromosome-positive.
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PMID:Acute lymphoid leukemia molecular phenotype in a patient with benign-phase chronic myelogenous leukemia. 834 Feb 87

Blast cells from an unselected consecutive series of 84 adults presenting with acute lymphoblastic leukemia (ALL) to St Bartholomew's Hospital over a seven year period were tested prospectively by cytogenetic and retrospectively by RT-PCR analysis for the presence of the Ph translocation and bcr-abl mRNA. This combination gave an overall figure of 20.3% for bcr-abl-positive and/or Ph-positive ALL. The incidence of bcr-abl-positive/Ph-positive ALL was most common between the ages of 31 and 50 years, becoming less common after the age of 50. Eight out of ten bcr-abl-positive patients expressed the e1a2 mRNA transcript, the other two expressed the b3a2 and b2a3 transcripts respectively. Cells from all patients with bcr-abl mRNA transcripts expressed the appropriate p190 or p210 bcr-abl protein and all were Ph-positive.
Leukemia 1993 Oct
PMID:Detection and significance of bcr-abl mRNA transcripts and fusion proteins in Philadelphia-positive adult acute lymphoblastic leukemia. 841 11


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