Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.1.1.69 (BMT)
2,655 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The bcr-abl RNA transcript is the molecular counterpart of the Philadelphia chromosome and is detectable by an extremely sensitive polymerase chain reaction assay in most patients with chronic myelogenous leukemia. To determine the effectiveness of ablative radiochemotherapy and bone marrow transplantation in eradicating molecular evidence of the malignant clone, we assayed for bcr-abl RNA expression in specimens from 19 patients with CML in chronic phase (CP) who have survived for at least one year post-BMT. We correlated these results with the patients' remission status based on cytogenetic analysis and BM morphology, and with evidence of mixed hematopoietic chimerism by analysis of RBC antigen and DNA restriction fragment length polymorphism patterns. Thirteen of the 19 patients had detectable bcr-abl RNA at some time following BMT. Twelve of these patients have remained in remission by morphologic and karyotypic criteria from 16.6 to 63.7 months following BMT. One of these 13 patients relapsed both by cytogenetic and clinical criteria at 28.1 months after BMT. Six of these 13 patients are still positive at the time of their most recent analysis. Only two patients have evidence for mixed chimerism of normal hematopoietic elements by either RBC antigen or DNA RFLP patterns. These results suggest that, in some patients transplanted for CML in CP, small numbers of residual leukemic cells may persist or reappear transiently without leading to clinical relapse. The definition of complete remission in CML may need to be revised in light of the enhanced ability to detect minimal residual disease by PCR technology.
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PMID:Persistence of bcr-able gene expression following bone marrow transplantation for chronic myelogenous leukemia in chronic phase. 167 85

We have utilized the polymerase chain reaction (PCR) to sensitively detect persistence of the chronic myelogenous leukemia (CML) malignant clone and to study bcr/abl mRNA splicing patterns following bone marrow transplantation. Thirteen of sixteen patients displayed persistent malignant cells during post-BMT clinical remission. In two patients bcr/abl mRNA was detected 4 and 9 months prior to clinical relapse. In eleven of fourteen patients in continued clinical remission malignant cells were detected post-BMT. Ten of these eleven patients were also cytogenetically normal. Seven patients have lost all evidence of bcr/abl transcript, but only at 1-2 years posttransplant, while four have shown persistence of the bcr/abl transcript from 28 days to 3 years post-BMT and one has converted from an initially negative result at 1 year post-BMT to detectable levels of chimeric mRNA at 2 years. Thus, 8/9 patients tested at or before 6 months, 7/12 at 1 year, and 3/10 at 2 years showed persistent detectable CML cells. Intriguingly, mRNA splicing patterns changed in 5 patients following BMT, with complete loss of mRNA containing bcr exon 3 (n = 2) or new appearance of mRNA not containing bcr exon 3 (n = 2). A single patient transiently lost evidence of bcr exon 3 expression while persistently expressing the bcr exon 2/abl exon 2 splice. Our data suggest that the majority of patients harbor small numbers of malignant cells following transplantation, and that such persistence may not inevitably predict clinical relapse. Complete elimination of the malignant CML clone post-BMT may rely on immunological mechanisms (e.g., graft-vs-leukemia).
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PMID:bcr/abl mRNA detection following bone marrow transplantation for chronic myelogenous leukemia. 175 65

The Polymerase Chain Reaction (PCR) was used to evaluate minimal residual disease in 21 Ph+ CML patients at various intervals after allogeneic bone-marrow transplantation (ABMT) by amplification of bcr-abl cDNA. All patients were cytogenetically Ph- at the moment of molecular analysis. Of these 76% were PCR negative, 24% positive for bcr-abl transcripts. 100% of the Cyclosporine A/Methotrexate treated patients (7/7) were negative. Severe chronic GvHD was twice as frequent in PCR positive patients (60%) than in negative ones (31%). The only patient who relapsed during follow up was PCR positive. The two longest survivors were PCR negative. These data are still insufficient for assessing the predictive value of PCR analysis in CML. Patients. 25 patients with Ph+ CML at diagnosis were enrolled in this study. Two died soon after BMT because of infection for failure of engraftment/early relapse, two were Ph chromosome positive and PCR+, and were therefore dismissed from this study. All remaining 21 patients were cytogenetically Ph- at the time of molecular analysis and underwent ABMT from matched donors. All patients were conditioned with cyclophosphamide and TBI: 330 cGy the three days prior to transplantation (990 cGy total, treatment B), or 200 cGy two times daily for three days (1200 cGy total, treatment A). In 3 cases the marrow was treated for GvHD prophilaxis with Campath alone or Campath plus BT 5/9 monoclonal antibodies (1). All patients were treated with Cyclosporin A (CS) 5 mg/kg i.v. from the day prior to transplantation until 25-30 days after; 9 of these were treated with CS plus Methotrexate (MTX).
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PMID:An assessment of chimeric transcript detection in CML patients after bone marrow transplantation. 187 98

Bone marrow transplantation is the only treatment that can result in long-term disease-free survival and possible cure in a significant number of patients with CML. Several prognostic features influence relapse and survival following allogeneic BMT for CML. The most important factor is treatment of patients during chronic phase. The timing of BMT in chronic phase CML remains controversial, because the Seattle findings that BMT done within a shorter interval from diagnosis to transplant was associated with improved survival has not been confirmed by the IBMTR. No factor can predict in the individual patient the timing of transformation, even in patients with low-risk chronic phase CML, but we believe that allogeneic BMT should be offered as soon as possible for newly diagnosed patients who have histocompatible siblings. More widespread application of BMT in CML is possible because of effective methods for preventing GVHD, the major cause of morbidity after allogeneic BMT. However, in vitro techniques for the depletion of donor marrow T cells have resulted in higher graft failure and relapse rates. More precise understanding of the immune mechanisms involved may permit more selective depletion techniques which not only abrogate GVHD but also permit sustained engraftment and preserve GVL effect. This may extend application of BMT for patients with mismatched related or histocompatible unrelated donors. It is of interest that cytogenetic relapse after BMT is not invariably followed by hematologic relapse. It is likely that the use of polymerase chain reaction techniques which detect the bcr-abl rearrangement at a very low level will identify the persistence of the malignant clone after allogeneic BMT in even more patients. At present, the significance of such findings is unclear, but further study of the kinetics of disappearance of the CML clone post-BMT may increase our understanding of the immune mechanisms involved in suppression of the malignant clone and determine whether in fact CML can be cured using BMT approaches.
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PMID:The evolving role of bone marrow transplantation in the treatment of chronic myelogenous leukemia. 218 97

BMT is the only curative therapy for CML, a uniformly lethal malignant disorder of the hematopoietic stem cell. Younger patient age and transplant in CP are associated with better outcome. Transplant within 1 year of diagnosis may provide a greater chance of survival than transplant at a longer interval from diagnosis. T-cell depletion of donor BM significantly reduces the incidence of acute and chronic GVHD, but is associated with an increased risk of graft failure and a marked increase in rate of relapse. Early results suggest that HLA-matched or partially HLA-mismatched unrelated donors may be used successfully in cases in which a suitably matched related donor is not available. Autologous transplantation of BM or PB stem cells can result in successful engraftment and possibly prolonged survival in some patients with CML. Following allogeneic BMT, some patients relapse cytogenetically without progressing to hematologic relapse. The use of PCR methodology to amplify bcr-abl transcripts has revealed persistence of the malignant clone in a substantial number of patients who are in hematologic and cytogenetic remission. The clinical significance and biologic mechanism(s) of this form of molecular relapse remain to be defined.
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PMID:Treatment of chronic myelogenous leukemia with bone marrow transplantation. 219 13

20 CML patients with hematological (5 pts) or only cytogenetic (15 pts) relapse occurring after allogeneic BMT have been treated with alpha-2b-interferon (IFN) at a starting dose of 5 x 10(6) IU/m2, subcutaneously, three times a week. All 5 patients with hematological relapse achieved hematological remission without reduction of bone marrow Ph1-positive cells. With a median follow-up of 43 months (range 6-48) from the hematological relapse, 3 patients are alive and 2 patients died from non-lymphoid blast crisis. 7 out of 15 patients with only cytogenetic relapse remain in hematological remission at a median of 37 months (range 3-45) from cytogenetic relapse, with 2 patients achieving complete cytogenetic remission confirmed at the molecular level by disappearance of the bcr rearranged band. With a median follow-up of 21 months (range 6-46), 8 patients progressed from cytogenetic to hematological relapse: 4 patients died from blast crisis and the other 4 patients are currently alive in chronic phase. For the 15 patients, the actuarial survival from BMT is 71% at 5 years.
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PMID:Alpha-2b-interferon as single therapy for patients with chronic myeloid leukemia relapsing after T-cell depleted allogeneic bone marrow transplantation. 227 45

Forty cases of Ph1-positive CML patients, who were followed up for a long period, were evaluated for bcr-abl mRNA using RT-PCR. We analyzed the relation of the bcr-abl mRNA subtype to the duration of chronic phase and blast crisis lineage. The mean duration of the chronic phase was 2 years 3 months (2Y3M) in b2-a cases, 1Y11M in b3-a, and 1Y4M in both b2-a and b3-a cases. The myeloid/lymphoid ratio at the blastic phase was 1.0 in b2-a, 0.33 in b3-a, and 2.5 in both mRNA cases. No significant difference was observed in the mean duration of the chronic phase and the frequency of two kinds of blast crisis lineage among different bcr-abl mRNA cases. We also evaluated CML patients in clinical remission after BMT. Bcr-abl mRNA was detectable in 6 of 7 cases (6/7) within 6 months after BMT, all five cases from 6 months to 1 year (1Y), 2/8 at 1Y, 3/7 at 2Y, and 3/7 over 3Y. It suggested the longer time after BMT, the more patients were negative for RT-PCR. In one patient, RT-PCR signal became undetectable at 9Y. This demonstrated that bcr-abl mRNA-positive residual cells could be eradicated long after BMT.
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PMID:[Molecular analysis of bcr-abl mRNA during long-term follow-up of cases of chronic myelogenous leukemia]. 796 54

Although serial detection of bcr-abl positive cells by PCR appears able to identify distinct patient groups with different risks of relapse following BMT, there remain many unanswered questions regarding the clinical utility and biological significance of PCR detectable cells in this disease. Many of the studies summarized have conflicting results and the influence of various clinical parameters which are known to affect the risk of relapse post-BMT has not yet been consistently associated with the ability to detect bcr-abl positive cells by PCR. These clinical parameters include GVHD, T-cell depletion and intensity of immunosuppression following BMT. Prospective studies with larger patient numbers will be necessary to define the impact of these factors in PCR status and relapse. The answers to all these questions will increase our understanding of the biology of chronic myelogenous leukemia and help provide more effective therapies for the future.
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PMID:Clinical significance of bcr-abl gene rearrangement detected by the polymerase chain reaction after allogeneic bone marrow transplantation in chronic myelogenous leukemia. 837 16

Bone marrow and/or peripheral blood of patients with chronic myeloid leukemia (CML) was investigated by the following three parameters: Ph' chromosome, bcr-abl expression in fresh blood and/or bone marrow, and bcr-abl expression in single hematopoietic progenitor colonies generated from blood and/or bone marrow. Expression of bcr-abl was proven by a reverse "nested primer" polymerase chain reaction (PCR) that is able to detect 1 pg of hybrid mRNA. We performed 108 investigations on 68 patients containing all three parameters: 12 on untreated patients, seven after interferon-alpha (IFN-alpha), seven after low-dose cytosine arabinoside (Ara-C), 22 after cyclic high-dose hydroxyurea (HU), 49 after allogeneic BMT, five before and three after stem cell mobilization, and three after autologous stem cell transplantation (ASCT). In 53 cases (49%), cytogenetics and PCR gave identical results. In 40 cases (37%), PCR from single colonies gave additional information compared to cytogenetics (e.g., mosaic in colonies when all metaphases were positive or negative). Most interesting were the results of one patient after IFN, one patient after ASCT, and 10 patients after BMT (14 investigations = 13%), showing only Ph'-negative mitoses accompanied by a negative nested primer PCR from fresh blood/bone marrow but single bcr-abl-positive progenitor colonies. False-positive results could be widely excluded by repeated insertion of negative controls into the experiments. One explanation for these results could be that CML, progenitors survive in the patient's body by being inactive and not proliferating. These cells express no or very little RNA and bcr-abl is not detectable by reverse PCR. When stimulated ex vivo in a colony assay by external growth factors, cells proliferate and produce detectable amounts of hybrid mRNA. The value of these observations is not clear. A follow-up of the patients will show if such sleeping progenitors can be activated in vivo. Concluding our observations, we can say that in special cases (therapy follow-up, detection of minimal residual disease) it could be useful to perform a PCR analysis of single progenitors in parallel with the routine investigations.
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PMID:Detection of bcr-abl mRNA in single progenitor colonies from patients with chronic myeloid leukemia by PCR: comparison with cytogenetics and PCR from uncultured cells. 854 60

Alpha-interferon (alpha-IFN) has been used in relapsed CML post-BMT, cytogenetic responses being attained in a number of cases (33 to 42%). In first chronic phase-CML patients such cytogenetic response has been correlated with the disappearance of the bcr region rearrangement, as seen with Southern-blot, but when RT-PCR is used only a small number of patients maintain undetectable traces of the Ph1 clone. A case of CML in haematological and cytogenetic relapse after BMT is reported who showed criteria of "accelerated" phase and, after treatment with alpha-IFN achieved haematologic, cytogenetic and molecular remission (Southern-blot and PCR negative) and disappearance of the abnormal clone with recovery of the donor haemopoiesis. The duration of the alpha-IFN cytogenetic response is longer than that of BMT (5 vs 3.5 yr), which is noteworthy. Taking the low toxicity of alpha-IFN into account, as compared with that of the other choices (a second BMT, IL2), this treatment should be offered to all patients with cytogenetic relapse after BMT.
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PMID:[Alfa-2a interferon induces molecular remission in post-BMT relapse of chronic myelogenous leukaemia. Report of a case with loss of bcr-abl RNA]. 855 77


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