BCR-ABL探针在慢性粒细胞白血病中的应用

目的用常规细胞遗传学（conventional cytogenetics,CC）和荧光原位杂交（fluorescence chromosomal in situ hybridization,FISH）技术检测Ph染色体。方法常规细胞遗传学分析（CC）,荧光原位杂交（FISH）技术。结果7例患者4例Ph染色体阴性,其中2例分别伴有t（18;22）和t（17;22）异常,其余2例为异基因造血干细胞移植后正常核型。一例培养后无中期分裂相。2例Ph染色体阳性,FISH结果bcr/abl（＋）细胞检出率分别为63.87%,84.51%,7.56%,4.0%,74.45%,67%,47%。结论常规细胞遗传学与荧光原位杂交技术相结合对CML患者诊断治疗过程中肿瘤负荷动态检测有显著意义。     

BCR/ABL fusion located on chromosome 9 in chronic myeloid leukemia with a masked Ph chromosome

A reciprocal translocation, t(10; 22) (q22; q11), resulting in a masked Ph chromosome was identified in a patient diagnosed with chronic myeloid leukemia (CML). Both homologs of chromosome 9 were of the normal pattern. Two signals for the ABL probe, both of them hybridized to chromosome 9, were demonstrated via fluorescence in situ hybridization (FISH). Furthermore, cohybridization with two differently labeled BCR/ABL translocation DNA probes indicated a BCR/ABL fusion apparently located on 9q34. Molecular studies revealed a rearrangement of the BCR region and expression of a chimeric BCR/ABL mRNA of CML configuration. These findings indicate that the BCR/ABL fusion resulted from an unusual relocation of the BCR gene from its normal position on 22ql I to 9q34 adjacent to the ABL gene.     

De novo hairy cell leukemia with a major BCR/ABL1 rearrangement: A case report with a literature review

Hairy cell leukemia (HCL) is a very rare mature B‐cell neoplasm and its simultaneous occurrence with chronic myeloid leukemia has been reported in only three cases. The pathogenesis and relationship of the two diseases are not clear. Here we report a case of HCL expressing a BCR/ABL1 clone, which showed molecular remission of the fusion clones and achieved partial remission over nine months of cladribine therapy. After a thorough analysis of previous studies and the results of this patient, we speculate that a subclone evolved to have an additional genetic BCR/ABL1 rearrangement. We also review all published literature on HCL with BCR/ABL1 rearrangement and discuss the pathophysiology of these unusual cases.     

Development of acute promyelocytic leukemia with isochromosome 17q after BCR/ABL positive chronic myeloid leukemia

We describe a pediatric case of acute promyelocytic leukemia with an i(17q) after treatment of BCR/ABL positive chronic myeloid leukemia (CML) for 3.5 years. The patient was treated with Busulphan, alpha-2a interferon, hydroxyurea, and cytosine arabinoside at various times in the course of the chronic phase of CML, because he had no HLA-identical donor for bone marrow transplantation. Hematologic remission was achieved for a short time, but cytogenetic remission was never possible. When promyelocytic blast crisis was diagnosed according to the French-American-British classification, cytogenetic studies revealed an i(17q) as a new feature in our patient. The promyelocytic transformation was associated with the appearance of an i(17q) preceding CML are discussed in the light of recent literature.     

ABL amplification in a patient with lymphoid blast crisis of chronic myelogenous leukaemia

 Although chronic phase myelogenous leukaemia (CML) is characterised by the Philadelphia (Ph) chromosome leading to a fusion of the BCR and ABL genes, additional genetic alterations involved in blast crisis are poorly understood. We report an at least 15-fold amplification of the ABL oncogene in a 29-year-old male patient with a variant Ph-positive t(19;22)(p13;q11.2) CML who presented in lymphoid blast crisis. Our finding suggests that an amplification of the ABL oncogene might play a part in the appearance of an aggressive phenotype in some cases of CML. Received: 27 July 1998 / Accepted: 26 October 1998     

Amplification of the BCR/ABL fusion gene clustered on a masked Philadelphia chromosome in a patient with myeloblastic crisis of chronic myelocytic leukemia

Although the chronic phase of chronic myelocytic leukemia (CML) is characterized by the Philadelphia (Ph) chromosome creating a hybrid BCR/ABL gene, additional genetic changes involved in blast crisis are poorly understood. We report a 4-8-fold amplification by tandem duplication of the BCR/ABL fusion gene clustered on a masked Ph chromosome in a 61-year-old male patient with CML in myeloblastic crisis. Our finding suggests that the BCR/ABL amplification may play a role as a novel mechanism in the progression to an aggressive blast transformation in some cases of Ph-positive CML.     

A Ph-negative chronic myeloid leukemia with a complex BCR/ABL rearrangement and a t(6;9)(p21;q34.1)

Chronic myeloid leukemia (CML) is a clonal malignant disorder of a pluripotent hematopoetic stem cell characterized by the presence of the Philadelphia (Ph) chromosome in more than 90% of patients. Cryptic or "masked" BCR/ABL gene rearrangements may be found in cases with a normal karyotype and in cases with the complex karyotype, in which typical t(9;22) is not visible at the microscopic level. Those rearrangements can now be detected by fluorescence in situ hybridization. Here, we report on a novel and complex Ph chromosome-negative CML case with a t(6;9)(p21;q34.1) in which the BCR/ABL fusion gene is located at 6p21.     

BCR/ABL amplification in chronic myelocytic leukemia blast crisis following imatinib mesylate administration

The onset of accelerated phase or blast crisis of chronic myelocytic leukemia (CML) is usually associated with the acquisition of new chromosome abnormalities in addition to the t(9;22)(q34;q11) that is characteristic of the chronic phase CML. We describe the cytogenetic and molecular genetic findings in two cases of myelocytic blast crisis of CML, one occurring 6 months after commencing treatment with the ABL-specific tyrosine kinase inhibitor imatinib mesylate (STI571, Glivec, or Gleevec) and the second treated with imatinib mesylate for established blast crisis. In both cases, multiple secondary cytogenetic abnormalities were observed at transformation, with homogeneously staining regions that were shown to contain BCR/ABL amplification by fluorescence in situ hybridization appearing after imatinib mesylate administration. BCR/ABL amplification is emerging as an important mechanism of acquired resistance to imatinib mesylate.     

Trisomy 11 in a patient with Ph-negative chronic myelogenous leukemia

A case of Ph-negative chronic myelogenous leukemia associated with functional reduction of platelets is described. Bone marrow cells examined in the blastic phase showed a stem line karyotype of 47,XY,+11.     

Studies of BCR and ABL gene rearrangements in chronic myelogenous leukemia patients by conventional and pulsed-field gel electrophoresis using gel inserts

Continual monitoring of the presence of the Philadelphia (Ph) chromosome in patients with chronic myelogenous leukemia (CML) is important for diagnosis as well as evaluation of therapy response of these patients. Because the Ph chromosome has been characterized molecularly to involve a reciprocal translocation between the ABL and BCR genes, there is an increasing interest in the use of molecular probes to detect chromosomal rearrangements in this disease. While rearrangements involving the bcr region of the BCR gene can be detected by conventional gel electrophoresis (CGE), detection of those involving ABL generally requires pulsed-field gel electrophoresis (PFGE). Currently, however, CGE and PFGE require different methods of cell preparation, with isolated DNA used in CGE and gel inserts containing whole cells used in PFGE. In this study, we show that the gel-insert method of DNA preparation can be adapted for use in CGE with slight modification of the gel-running conditions. The advantages of this method are demonstrated by studying both bcr and ABL rearrangements in bone marrow and peripheral blood samples of CML patients. Furthermore, we report a novel finding that chromosomal breakpoints in the ABL gene of CML patients occur predominantly between exons 1b and 1a.     

Deletion of BCR region 3' in chronic myelogenous leukemia.

The t(9;22)(q34;q11) produces the BCR/ABL fusion gene which codifies a 210 kb protein with a strong tyrosine kinase activity and is involved in cellular development and growth. Because this translocation is a reciprocal event, it could give rise to a second fusion gene, ABL-BCR, on the derivative 9q+. We analyzed the influence of the 3' M-BCR deletion on the clinical picture at diagnosis and disease outcome in 57 patients with a clinical diagnosis of CML. Molecular studies were done on DNA from peripheral blood leukocytes or bone marrow with the restrictions enzymes BglII, EcoRI, HindIII, and BamHI, and the BCR 3' probe (transprobe 1) (Oncogene Science Inc.), which encompasses almost all of the 5.8 Kb of the M-BCR gene area. In 18 patients Southern blot analysis showed deletion of the 3' end of BCR gene (32.7%). There were no significant differences between patients with or without deletion, either in the clinical and laboratory data at the disease diagnosis or at the disease outcome. The absence of differences between the patients with and without 3' BCR deletion supports the hypothesis that the hybrid gene ABL-BCR does not have an important role in leukemogenesis in CML cases.     

Deletion of any part of the BCR or ABL gene on the derivative chromosome 9 is a poor prognostic marker in chronic myelogenous leukemia

To evaluate the prognostic significance of submicroscopic deletions of the ABL or BCR gene associated with t(9;22) in chronic myelogenous leukemia (CML), we investigated the incidence of an ABL or BCR deletion on derivative chromosome 9 using fluorescence in situ hybridization (FISH). FISH was performed using the LSI BCR/ABL dual-fusion translocation probe on bone marrow cells of 86 patients with CML. Of 86 patients, ABL deletion was detected in 13 (15.1%) patients and BCR deletion in 8 patients (9.3%). Patients with ABL deletion showed shorter event-free survival time (EFS) than those without ABL deletion (P = 0.020). Patients with BCR deletion showed significantly short overall survival time (OS; P = 0.039). Patients with ABL and/or BCR deletion (14/86 patients, 16.3%) showed significantly short OS and EFS (median OS, 43.0 months; median EFS, 40.0 months), compared to the patients without any BCR or ABL gene deletions (median OS, 94.0 months; median EFS, 90.0 months; P = 0.041 for OS, P = 0.008 for EFS). All the patients with BCR deletion, except for one, had a concomitant ABL deletion, suggesting that BCR deletion occurs in conjunction with ABL deletion. In patients with ABL deletion only, BCR/ABL rearrangement with b2a2 mRNA type tended to be more frequent than in patients without any deletion of the two genes (P = 0.073). Deletion of any of the BCR or ABL genes on derivative chromosome 9 was associated with both short OS and EFS. We conclude that deletion of not only the ABL gene, but also of the BCR gene, is a poor prognostic marker that indicates rapid disease progression in CML.     

Detection of the gene rearrangement in chronic myelogenous leukemia with biotinylated gene probes

The breakpoint cluster region gene rearrangement associated with chronic myelogenous leukemia is becoming important in the diagnosis and management of the disease. At this time, the ability to demonstrate the gene rearrangement is limited to a few research laboratories. The problem results partially from unfamiliarity of medical laboratory personnel with DNA technology, but more because of the restricted use of radiolabeled phosphorus in hospital laboratories. With the introduction of biotinylated deoxynucleotides, nucleic acid hybridization procedures can now be performed without the use of radioisotopically labeled gene probes. This article describes the use of biotin-labeled gene probes to detect the gene rearrangement of the breakpoint cluster region of chromosome 22 in chronic myelogenous leukemia. The techniques are reproducible, sensitive, and safe. With the procedures described in this article, the assay can become more available to medical laboratories interested in offering this diagnostic and decision-making tool.     

9q34 rearrangements in BCR/ABL fusion-negative acute lymphoblastic leukemia

The t(9;22)(q11.2;q34) translocation is found in a subset of acute lymphoblastic leukemia (ALL). The presence of this translocation involving the fusion of BCR/ABL genes represents a poor prognostic group. Because of the importance in detecting t(9;22) in ALL patients and because occasionally a cytogenetically cryptic BCR/ABL fusion is detected with fluorescence in situ hybridization (FISH), our laboratory routinely performs BCR/ABL FISH tests on all newly diagnosed ALL patients. In the past year, 25 consecutive, newly diagnosed, untreated ALL cases were analyzed. We report the cytogenetics and FISH findings of three cases containing a rearranged 9q34 region with an intact BCR (22q11.2) region and an absence of the BCR/ABL fusion. A split ABL signal representing a translocation of the 9q34 region with chromosome segments other than 22q11.2 (BCR) was observed in 3 cases. Two of these patients were 3 years old; one was 21 at the time of diagnosis. A split ABL FISH signal without the involvement of BCR does not represent a t(9;22) translocation, and prognostic implications of this apparent subgroup of ALL cases have not been determined. Cytogenetic, pathologic, and clinical aspects of these three cases are presented.     

慢性粒细胞白血病患者骨髓来源Flk1+CD31-CD34-间充质干细胞中 BCR/ABL融合基因的检测

背景：免疫表型为Flk1+CD31-CD34-的间充质干细胞体内外实验研究均证实在单细胞水平可以向造血及内皮细胞分化。 目的：观察慢性粒细胞白血病患者骨髓BCR/ABL融合基因的表达情况。 方法：体外培养扩增慢性粒细胞白血病患者骨髓来源原始间充质干细胞,测定其生长曲线,分析其细胞周期及免疫表型,使用RT-PCR和FISH的方法检测其BCR/ABL融合基因的表达情况。 结果与结论：慢性粒细胞白血病患者骨髓来源的原始间充质干细胞呈成纤维样生长,大部分细胞处于G0/G1期,并且高表达Flk1,CD13,CD29,CD44,用RT-PCR和FISH的方法能够检测出BCR/ABL融合基因的表达。提出慢性粒细胞白血病的白血病基因转化可能发生在比造血干细胞更高的血液血管干细胞水平上。