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: UMLS:C0023467 (acute myeloid leukemia)
35,200 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Autologous peripheral blood stem cell transplantation (PBSCT) is replacing autologous bone marrow transplantation (BMT) in the treatment of leukemia. One of the potential advantages of autologous PBSCT is the possibility that peripheral blood stem cells (PBSC) are less likely to be contaminated by leukemic cells than bone marrow grafts. However, the major problem still remains the high incidence of leukemic relapse following autologous PBSCT, which may be caused by the reinfusion of PBSC contaminated by leukemic cells. Recently, we have developed a quantitative assay using competitive reverse transcriptase polymerase chain reaction that estimates the number of AML1/ETO transcripts in t(8;21) acute myelogenous leukemia (AML), in order to determine the degree of leukemic cell contamination in PBSC harvests, and to monitor minimal residual disease (MRD) quantitatively in patients with t(8;21) AML. Our data indicate that although PBSC harvests collected after consolidation chemotherapy are contaminated by leukemic cells, the degree of leukemic cell contamination decreases with repeated cycles of chemotherapy. Furthermore, the MRD in PBSC harvests is less than in the corresponding bone marrow obtained on the day of the PBSC collection. There appears to be no relationship between the number of AML1/ETO transcripts found in the infused PBSC harvests and the incidence of leukemic relapse following autologous PBSCT in our study. However, a substantial decrease of AML1/ETO transcripts was seen following autologous PBSCT. Thus, the quantitative analysis of AML1/ETO transcripts may be clinically useful in patients with t(8;21) AML.
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PMID:Significance of quantitative analysis of AML1/ETO transcripts in peripheral blood stem cells from t(8;21) acute myelogenous leukemia. 913 Jun 15

We report a 3-year-old girl with minimally differentiated acute myeloid leukemia and chromosome 16 inversion (inv 16). Inv 16 is generally associated with acute myelomonocytic leukemia with dysplastic eosinophils in the bone marrow (AML-M4Eo). Recently, molecular analysis showed that a fusion gene is generated by this inversion between the CBFB gene on the q arm and the MYH11 gene on the p arm. Using reverse transcriptase-polymerase chain reaction analysis, we tried to detect CBFB/MYH11 chimeric mRNA in blasts from our patients, however, were unable to detect any chimeric mRNA in the blasts: The absence of CBFB/MYH11 transcripts in this case suggests that rare chimeric products might be formed as a result of inv 16 that could not be detected by the primer sets used in this study. Another possibility is that different genes are rearranged on the chromosome 16 with the inv 16. More detailed molecular analysis of this case might be necessary in order to elucidate these possibility. Analyzing leukemias with inv 16 which do not have a typical CBFB/MYH11 chimeric mRNA might lead to understanding an alternative pathogenesis for acute leukemia with inv 16.
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PMID:Molecular analysis of minimally differentiated acute myeloid leukemia with chromosome 16 inversion. 915 61

The FHIT (fragile histidine triad) gene on chromosome 3p14 is a candidate tumor suppressor gene, and its transcripts are shown to be abnormal in several human cancers. We examined 40 leukemia samples for the alterations of FHIT transcripts by reverse transcriptase-polymerase chain reaction (RT-PCR) and direct sequencing. Intact FHIT mRNA was not detected in two patients with acute myeloid leukemia (AML) and in one patient with chronic lymphocytic leukemia (CLL). The three cases expressed only an aberrant FHIT mRNA lacking exons 3 to 6 (FHIT delta 3-6 mRNA), which could encode a polypeptide of 13 amino acids. Southern blot analysis on two samples from these cases showed no rearrangements of the FHIT gene. Although intact FHIT mRNA was detected as the main band in the remaining 37 samples, 33 of them (14 of 14 AML, 11 of 13 chronic myeloid leukemia, five of five acute lymphocytic leukemia, and three of five CLL) expressed aberrant FHIT delta 3-6 mRNA. We barely detected the FHIT delta 3-6 mRNA in only one of 25 normal control samples. Our results suggest that loss of the normal FHIT function may be involved in the genesis of at least some human leukemias and that expression of aberrant FHIT transcripts is rather specific and frequent in leukemia samples.
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PMID:Decreased or altered expression of the FHIT gene in human leukemias. 917 Feb 14

Using a quantitative reverse transcriptase PCR assay, the mRNA expression of five putative drug resistance-related genes were assessed in normal peripheral (n = 14) and bone marrow (n = 4) mononuclear cells from healthy donors and patients with acute myeloid leukaemia (n = 11). The mRNA levels of MDR1, the multidrug resistance-associated protein and glutathione-S-transferase pi were equally expressed in both compartments. Bcl-2 mRNA was slightly higher in the leukaemic marrow samples. However, topoisomerase II alpha mRNA levels were found to be much higher in normal and leukaemic marrow cells compared to peripheral blood (p < 0.01), which may, in part, reflect the different proliferation pattern of the mononuclear cells in the two compartments. Such findings could be important for researchers using bulk assays in a mix of samples from peripheral blood or bone marrow to investigate prognostic factors in patients with leukaemia.
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PMID:mRNA expression, measured by quantitative reverse transcriptase polymerase chain reaction, of five putative drug resistance parameters, in normal and leukaemic peripheral blood and bone marrow. 921 Sep 6

16;21 translocation is a recurrent primary abnormality in acute myeloid leukemia (AML). The genes involved in this translocation are ERG on chromosome 21 and TLS/FUS on chromosome 16. The rearrangement of the two chromosomes forms the TLS/FUS-ERG fusion gene and produces a consistent chimeric transcript on the der (21) chromosome. In this study, we analyzed the clinical characteristics of 19 patients with t(16;21)-AML, including 2 patients who evolved from myelodysplastic syndrome, and detected the chimeric transcripts of the TLS/FUS-ERG fusion gene in the patients during various clinical stages by the reverse transcriptase-polymerase chain reaction (RT-PCR) technique. We found that the patients with t(16;21) are characterized by a relatively younger age (median age, 22 years old), involvement of various subtypes of French-American-British classification and a poor prognosis: 18 of the 19 patients died of the disease (median survival was 16 months). Four types of TLS/FUS-ERG chimeric transcripts including a novel type were noted in the RT-PCR analysis. The novel transcript contained an additional 138 nucleotides consisting of TLS/FUS exon 8 and ERG exons 7 and 8 and had an in-frame fusion. These chimeric transcripts were consistently detectable in the samples obtained not only at diagnosis and relapse but also in short and long complete remission, suggesting that t(16;21)-AML is resistant to conventional chemotherapy. Thus, we recommend that t(16;21) should be monitored by RT-PCR even in clinical remission and the patients should be treated by other more powerful modality like stem-cell transplantation in the first remission.
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PMID:Consistent detection of TLS/FUS-ERG chimeric transcripts in acute myeloid leukemia with t(16;21)(p11;q22) and identification of a novel transcript. 924 52

We report a case of Philadelphia (Ph)-positive AML in which interphase fluorescence in situ hybridization (FISH) analysis was performed from diagnosis throughout the course of therapy using major (M-) breakpoint cluster region (BCR)/minor (m-) BCR and ABL cosmid probes. We also investigated the existence of the M-BCR or m-BCR at the RNA or DNA level by the reverse transcriptase polymerase chain reaction and Southern blot analysis, respectively. Complete remission with a normal karyotype was achieved after several regimens of chemotherapy and peripheral blood stem cell transplantation (PBSCT), but relapse occurred and his cells became 100% Ph-positive. We detected the m-BCR/ABL fusion gene by interphase FISH analysis using an m-BCR/ABL translocation probe, and found that FISH analysis was useful for classifying the BCR, identifying minimal residual disease, and for predicting imminent relapse after chemotherapy and PBSCT.
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PMID:Sequential interphase FISH analysis of m-BCR/ABL chimeric gene-positive cells in Ph-positive acute myeloid leukemia. 925 Aug 5

The Wilms' tumor gene (wt1) is strongly expressed in malignant blasts of acute myeloid leukemia (AML) in approximately 80% of all cases. However, the role of wt1 expression in non malignant hematopoietic cells remains unclear. To characterize the expression of wt1 in differentiating hematopoietic progenitors, we isolated and cultured CD34+ progenitor cells from four healthy bone marrow donors with stem cell factor (SCF) and granulocyte colony stimulating-factor (G-CSF) to induce differentiation into granulocytes. Four different cultures were carried out for 12 days. During culture, wt1 mRNA expression was analyzed by defining its ratio relative to beta-actin using reverse transcriptase polymerase chain reaction (RT-PCR). To monitor the stage of differentiation, expression of cell surface markers and peroxidase was analyzed daily. The initial purity of CD34+ cells ranged between 80% and 90%; after 12 days, the frequency of neutrophil bands and segmented neutrophils was approximately 60%. Using RT-PCR to determine the ratio of wt1 to beta-actin expression, we reproducibly detected maximum expression of wt1 mRNA at day 0 in two cultures and at day 1 in two other CD34+ cell cultures; at both these time points nearly all cells fulfilled the morphological and immunephenotypical criteria of early hematopoietic blast cells. Wt1 expression dropped rapidly at day 1 and 2, respectively, in these two pairs of cultures, and was accompanied by an increase of cells expressing CD33 surface antigen. Our data suggest that wt1 expression is restricted to a subset of CD34+ progenitors and downregulated in later stages of differentiation in vitro.
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PMID:The Wilms' tumor gene is expressed in a subset of CD34+ progenitors and downregulated early in the course of differentiation in vitro. 925 7

CBP, which is located on 16p13 and encodes a transcriptional adaptor/coactivator protein, has been shown to fuse by the t(8;16)(p11;p13) translocation to MOZ on 8p11 in acute myeloid leukemia. We found a t(11;16)(q23;p13) in a child with therapy-related chronic myelomonocytic leukemia. Subsequent reverse transcriptase-polymerase chain reaction and direct sequencing analyses revealed the MLL-CBP fusion transcript in CMML cells. Because 11q23 translocations involving MLL and t(8;16) involving MOZ and CBP have been reported in therapy-related leukemias, both the MLL and CBP genes may be targets for topoisomerase II inhibitors. Accordingly, we believe that most t(11;16)-associated leukemias may develop in patients who have been treated with cytotoxic chemotherapy for primary malignant diseases.
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PMID:Novel MLL-CBP fusion transcript in therapy-related chronic myelomonocytic leukemia with a t(11;16)(q23;p13) chromosome translocation. 929 Sep 55

The present study was undertaken to assess the predictive value of pretherapeutic determinants of ara-C metabolism and proliferative activity of leukemic blasts for early response to antileukemic therapy in the setting of granulocyte-macrophage colony-stimulating factor (GM-CSF)-based priming before and during TAD-9 induction in 36 consecutive patients with de novo acute myeloid leukemia (AML). Ara-C metabolism was assessed by the activities of deoxycytidine kinase (DCK), deoxycytidine deaminase (DCD), DNA polymerase alpha (Poly alpha), and overall polymerase (overall Poly). The fraction of cells in S phase (%S phase) and thymidine kinase (TK) activity were determined as a measure of proliferative activity. Early response to therapy was defined by the percentage of leukemic blasts in the bone marrow 5 to 7 days after completion of TAD-9 with less than 5% signaling an adequate response and greater than 5% indicating an inadequate early reduction, respectively. While neither %S phase, DCK, nor overall Poly activity were predictive for early response, TK and Poly alpha activities were significantly higher for cases with adequate blast cell clearance. The respective median values were for TK 3.8 versus 1.85 pmol/min/mg protein (P = .012), and for Poly alpha 1.9 versus 0.69 pmol/min/mg protein (P = .014). An inverse relation was detected for DCD activity which was significantly lower in responding patients with a median of 0.33 nmol/min/mg protein (range, 0.0 to 29.5) as compared to a median of 5.1 nmol/min/mg protein (range, 0.11 to 8.45) in early nonresponders, (P = .009). Taking the respective median values as arbitrary cut-points for high or low enzyme activities, responders and nonresponders could be discriminated prospectively. Hence, 14 of 16 cases (88%) with DCD activities below the median of 1.56 nmol/min/mg protein responded as compared to only 3 of 14 (22%) patients with higher DCD activities (P = .0004). From the 15 patients with TK activity above the overall median of 3.2 pmol/min/mg protein, 11 cases (73%) achieved an adequate blast cell clearance while only 6 of 17 cases (35%) with lower values responded (P = .035). Similarly, 12 of 15 patients (80%) with high Poly alpha levels (>1.22 pmol/min/mg protein) responded to induction therapy as compared to only 5 of 14 patients (36%) with lower enzyme activities (P = .02). By logistic regression analysis of enzyme activities, DCD activity was found to be the most sensitive parameter to predict an adequate blast cell clearance (P = .032). Activities of DCD and TK were not only associated with initial response but were also found predictive for remission duration. Hence, from 11 patients with low TK levels 8 (73%) relapsed within 1 year, whereas only 2 of 11 (18%) patients with high TK activity experienced a recurrence of their disease (P = .015). Six of 9 (66%) patients with higher than median DCD levels relapsed within 1 year, whereas 10 of 14 patients (71%) with lower DCD levels had a longer remission duration (P = .085). Analysis of DCD gene expression at the mRNA level by a semi-quantitative reverse transcriptase-polymerase chain reaction method showed that a high transcription rate of the DCD gene was associated with high enzyme activities and vice versa. Hence, the observed intraindividual differences in DCD activity are a reflection of differences in gene activity and transcription rate rather than of variants in translation. Although further analyses are needed to elucidate the molecular mechanisms that determine the variation of enzyme activities in individual patients, the present study strongly suggests that pretherapeutic determination of TK and Poly alpha as well as of DCD allows to predict response to TAD-9 + GM-CSF induction therapy and may provide the means for the development of a risk adapted treatment strategy.
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PMID:Activity of thymidine kinase and of polymerase alpha as well as activity and gene expression of deoxycytidine deaminase in leukemic blasts are correlated with clinical response in the setting of granulocyte-macrophage colony-stimulating factor-based priming before and during TAD-9 induction therapy in acute myeloid leukemia. 929 31

We describe a method of spectrophotometric detection of BCR/ABL chimeric sequences amplified by multiplex reverse transcriptase-polymerase chain reaction (RT-PCR), enabling the use of archival hematologic slides as RNA sources. Multiplex PCR amplified b3a2, b2a2, and e1a2 break points of the BCR/ABL translocation and the normal ABL gene product. Assessment of sensitivity, performed on K562 cells, showed that the threshold approximated radioactive methods of detection (i.e., 1 positive cell in 1 x 10(6) negative cells for single round PCR and lower than 1 positive cell in 1 x 10(7) negative cells for nested PCR). Then, we assayed 38 different archival hematologic slides from 18 patients, including 11 cases of chronic myelogenous leukemia or chronic myelogenous leukemia-like disease, such as a case of myelofibrosis and a case of chronic neutrophilic leukemia, 6 cases of acute lymphoblastic leukemia, and 1 case of acute myelogenous leukemia. Amplification and spectrophotometric detection of BCR/ABL fusion messenger RNAs gave an unambiguous positive result in 24 (89%) of 27 expected positive slides, among which 17 (63%) were positive after a single PCR round. Concordant unambiguous results were obtained from 35 (92%) of 38 slides, as verified through parallel analyses of corresponding cryopreserved cells. Retrospective analysis on archival hematologic slides yielded identification of the presence or absence of the t(9;22) translocation and break point in 14 previously uncharacterized cases. The application of this method can help define the diagnosis of cases lacking other appropriate material and assist in the retrospective analysis of large patient series for which only smears are available.
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PMID:Spectrophotometric detection of RT-PCR-amplified BCR/ABL fusion transcripts. A survey performed on archival hematologic slides. 932 90


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