Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.6 (RNA polymerase)
 34,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Reverse transcriptase polymerase chain reaction (RT-PCR)-based assays to detect occult neoplastic cells offer the highest sensitivity for the study of tumour dissemination and minimal residual disease. The detection of small numbers of tumour cells in a clinical sample may result in a redefinition of what constitutes residual disease and relapse, affecting future patient management. However, there remains disparity in the published data on the clinical value of RT-PCR for the detection of circulating tumour cells. This most likely reflects differences in the methods for sample preparation, RNA extraction, and cDNA synthesis among laboratories. Consequently the need for implementation of standard quality control measures is pressing in order to facilitate meaningful assessment of the methodology and it's clinical value. A 2-day workshop organized by the immunotherapy subgroup of the EORTC Melanoma Cooperative Group was held on this topic at the Ludwig Institute in Epalinges-sur-Lausanne, Switzerland in January 1996, with Stefan Carrel as the local host. Many pertinent issues were discussed in great detail, covering every step from sample handling to quality control. This workshop resulted in a concerted action leading to the preparation of laboratory guidelines, which are summarized in this review.
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PMID:Polymerase chain reaction detection of circulating tumour cells. EORTC Melanoma Cooperative Group, Immunotherapy Subgroup. 957 29

Peripheral blood stem cell support allows dose intensification of multiple cycle chemotherapy for metastatic tumors, including pediatric sarcomas. The VACIME protocol (vincristine, adriamycin, cyclophosphamide, ifosfamide, mesna and etoposide) utilizes peripheral blood stem cells (PBSC) collected following the treatment cycle as support for subsequent dose- and time-intensive chemotherapy. A critical assumption is that PBSC collected in this manner will be purged of residual tumor cells in vivo. We tested this assumption using sensitive reverse-transcriptase polymerase chain reaction (RT-PCR) to assess the presence of the characteristic translocations of the Ewing's sarcoma family of tumors (ESFT) and alveolar rhabdomyosarcoma (ARMS), t(11;22), and t(2;13), respectively. We used RT-PCR to evaluate 122 samples of peripheral blood (PB), bone marrow (BM) and PBSC collected from 12 pediatric patients with metastatic ESFT and ARMS. The samples included pre-therapy BM and PB, as well as BM, PB, and PBSC collections at various times in the VACIME treatment course. Molecular evidence of tumor contamination was detected in 1/40 PBSC collections from 12 patients. In all patients, we documented clearance of disease by RT-PCR in peripheral blood and bone marrow by week 9 of the VACIME protocol. In vivo purging in combination with the intensive VACIME regime appears to be effective in removing tumor cells from PBSC, bone marrow, and peripheral blood as detected by RT-PCR.
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PMID:RT-PCR evaluation of peripheral blood, bone marrow and peripheral blood stem cells in children and adolescents undergoing VACIME chemotherapy for Ewing's sarcoma and alveolar rhabdomyosarcoma. 1048 38

The management of chronic myelogenous leukemia (CML) has become complex due to the availability of improved diagnostic procedures and life-prolonging or even curative treatment strategies that are more successful the earlier they are applied in the course of the disease. This is true for allogeneic bone-marrow transplantation, treatment with interferon alpha (IFN) and Philadelphia-negative stem-cell collections for autografting. Outcome differs according to risk profiles of patients at diagnosis. In addition, molecular techniques for the detection of the BCR-ABL fusion gene or its products, such as the reverse-transcriptase polymerase chain reaction (PCR), Southern blot analysis, or fluorescence in situ hybridization, facilitate accurate diagnosis and the monitoring of residual disease. They allow the individualization of treatment such as early infusion of donor lymphocytes if molecular relapse is detected after allografting, or discontinuation of IFN in the presence of very low BCR-ABL transcript levels). The availability of real-time PCR devices further improves and accelerates the diagnosis and monitoring of residual disease. This article addresses recent developments in drug therapy and allografting, including treatment intensification with low-dose ara C or intensive chemotherapy followed by autografting, introduction of new drugs (such as homoharringtonine or tyrosine kinase inhibitor STI571), progress with unrelated donor transplantations, use of peripheral blood stem cells for allografting, and transplantation without myeloablative conditioning. Tradeoffs between the treatment options will be discussed in the context of the evidence-based guidelines for treating CML, as recently published by the American Society of Hematology. Finally, the new competence network on acute and chronic leukemias will be introduced.
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PMID:Current trends in the management of chronic myelogenous leukemia. 1096 82

Benign mesenchymal neoplasms associated with rearrangements of the DNA architectural factor gene HMGIC on chromosome 12 include lipomas, uterine leiomyomata, pulmonary chondroid hamartomas, endometrial polyps, salivary gland pleomorphic adenomas, and breast fibroadenomas. Although HMGIC also has been implicated in the pathobiology of aggressive angiomyxoma of the vulva, the molecular mechanisms pertaining to this neoplasm are unclear. Tissue from a recurrent aggressive angiomyxoma was investigated by cytogenetic and expression analysis for HMGIC and HMGIY. The trypsin-Giemsa-banded karyotype showed a clonal translocation between chromosomes 8 and 12 [46,XX,t(8;12)(p12;q15)]. Fluorescence in situ hybridization (FISH) analysis with whole chromosome paint probes for chromosomes 8 and 12 excluded cryptic involvement of other chromosomes. The chromosome 12 breakpoint was mapped with two-color FISH analysis using cosmid probes at the 5' and 3' termini of HMGIC. Both cosmid probes showed hybridization to the normal chromosome 12 and the der(12) chromosome, indicating that the breakpoint was 3' (telomeric) to the gene. Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis revealed HMGIC expression in the tumor, and immunohistochemistry localized HMGIC expression to the tumor's spindle cells. Like numerous benign mesenchymal tumors, this locally aggressive tumor is associated with rearrangements near or within HMGIC, but chimeric gene formation was not required for tumorigenesis. Inappropriate expression of this DNA binding protein, however, may be important in the pathobiology of this tumor. Understanding the pathogenetic mechanism may also be helpful in developing new diagnostic tools for identifying residual disease.
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PMID:Chromosomal translocation t(8;12) induces aberrant HMGIC expression in aggressive angiomyxoma of the vulva. 1155 Feb 85

Detection of BCR-ABL transcripts in chronic myeloid leukaemia (CML) is used to confirm the diagnosis and to monitor residual disease. Quantitative techniques are required to predict response to therapy or early relapse. We have evaluated an assay in which transcription-mediated amplification (TMA) of BCR-ABL and ABL transcripts is achieved using reverse transcriptase and RNA polymerase. The products are quantified in the hybridisation protection assay (HPA) using acridinium ester-labelled DNA probes and chemiluminescence. The method is a single tube procedure which uses small amounts of RNA (<500 ng/triplicate analysis), is technically simple (requiring just two waterbaths and a luminometer), rapid (total assay time <4 h) and sensitive (capable of detecting one BCR-ABL-positive K562 cell in the presence of 10(4)-10(5) BCR-ABL-negative cells). BCR-ABL signals from patient RNA samples were quantified relative to known amounts of K562 RNA and normalised to levels of ABL. BCR-ABL/ABL ratios ranged from 0.15 to 1.59 (median 0.65) in RNA from diagnostic blood or bone marrow of 18 CML patients and were < or =0.0001 in 20 normal controls. Sequential samples analysed from six CML patients post-allogeneic bone marrow transplantation who relapsed and received donor lymphocyte infusions showed BCR-ABL/ABL ratios which reflected patient status or treatment. A BCR-ABL/ABL ratio of 0.01 served as a useful arbitrary indicator value, with results above and below this value generally correlating with relapse or remission, respectively.
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PMID:Transcription-mediated amplification and hybridisation protection assay to determine BCR-ABL transcript levels in patients with chronic myeloid leukaemia. 1189 44

Recent advances in molecular genetics impact the health care and outcome of patients with acute lymphoblastic leukemia (ALL). BCR-ABL, a common molecular defect in adult ALL, is a valuable tumor marker whose detection influences prognosis and clinical management decisions. Molecular methods such as fluorescence in situ hybridization (FISH), reverse-transcriptase polymerase chain reaction (rtPCR), and real-time quantitative rtPCR can be used to detect the chimeric BCR-ABL gene or its transcripts. These molecular assays improve our ability to measure residual disease and to estimate risk of relapse. On the horizon are gene expression profiles that will likely provide additional information beyond what is obtainable with current clinical and laboratory approaches.
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PMID:Clinical applications of BCR-ABL molecular testing in acute leukemia. 1270 70

Residual disease in chronic myeloid leukemia patients may be assessed by various molecular methods. After imatinib treatment a significant proportion of patients achieve complete cytogenetic remission (CCR) and a sensitive method is necessary to monitor treatment response and to detect early signs of relapse. Reverse-transcriptase polymerase chain reaction (RT-PCR) is by far the most sensitive approach to assess residual disease in this group of patients. Qualitative PCR methods give only limited information about the residual leukemic mass. Quantitative RT-PCR (Q-PCR) assays enable to monitor the kinetics of residual BCR-ABL transcripts over time in patients with a good response to imatinib. Early Q-PCR results on imatinib treatment can help to identify individuals who are likely to have a good response. In chronic phase patients after CCR, Q-PCR may identify patients who are likely to continue with their CCR or to relapse and may help to optimize treatment for this group of patients. The definition of molecular surrogate endpoints beyond CCR for studies which are currently planned demands standardization of the nomenclature and of technologies to measure these targets.
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PMID:Molecular surveillance of chronic myeloid leukemia patients in the imatinib era - evaluation of response and resistance. 1517 8

Cancer-related deaths are caused principally by recurrence and metastasis arising from residual disease, whose therapeutic responses has been suggested to be substantially different from primary tumors. However, experimental animal models designed for evaluating the therapeutic responses of residual disease are mostly lacking. To overcome this deficiency, we have developed a preclinical model that recapitulates the progression for advanced nonsmall cell lung cancer (NSCLC). An archived Lewis lung carcinoma mouse tumor, propagated only through serial in vivo transplantation and never adapted to cell culture, was stably labeled using lentivirus-encoded biomarkers, consistently expressed through an RNA polymerase II promoter. Labeled tumors were inoculated into syngeneic immunocompetent mice to ensure superior tumor-host interactions. Primary tumors were resected on reaching a predetermined size, followed by treatment in a setting akin to postsurgical first-line adjuvant chemotherapy and routine imaging to monitor the progression of pulmonary metastasis. We discovered that efficacious treatment, instead of reducing disease growth rates, significantly prolonged disease-free survival and overall survival. As in the clinic, cisplatin-based regimes were more effective in this model. However, the response of metastases to specific agents could not be predicted from, and often opposed, their effects on subcutaneous "primary" tumors, possibly due to their distinct growth kinetics and host interactions. We here introduce a clinically relevant model of residual metastatic disease that may more accurately predict the therapeutic response of recurrent, metastatic disease.
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PMID:Preclinical therapeutic response of residual metastatic disease is distinct from its primary tumor of origin. 2131 95

The International Randomized Study of Interferon vs. STI571 (IRIS) trial that investigated the use of the tyrosine kinase inhibitor (TKI) imatinib (versus interferon) changed the treatment and outcome of chronic myeloid leukemia (CML). Long-term follow-up of IRIS patients has defined response parameters and methods of tracking residual disease with cytogenetic testing of bone marrow metaphases and molecular monitoring of BCR-ABL transcripts using quantitative reverse-transcriptase polymerase chain reaction. Cytogenetic and molecular responses are now considered useful surrogates for long-term outcome. Early and robust response to imatinib predicts positive long-term outcomes. However, 15-25% of patients fail initial treatment or become intolerant of imatinib and need increased doses or alternate treatment. Second-line treatment with the second-generation TKIs nilotinib and dasatinib have resulted in favorable rates of progression-free survival (PFS) and overall survival. Data from the ENESTnd (nilotinib) and DASISION (dasatinib) trials in newly diagnosed chronic-phase CML patients demonstrated more robust and rapid complete cytogenetic (77-80%) and major molecular responses (43-46%) at 12 months compared with imatinib (65-66% and 22-28%). The relationship between a complete cytogenetic response at 12 months and long-term PFS supports a role for second-generation TKIs as first-line treatment of newly diagnosed chronic-phase CML.
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PMID:Interpretation of cytogenetic and molecular results in patients treated for CML. 2141 37