7 research outputs found
Diagnosis and genetic subtypes of leucemia combining gene expression and flow cytometry.
No full textAcute leukemia, defined as a genetic disease, is the most common cancer in children representing about one half of all cancers among persons younger than 15 years. Acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML) each represents a heterogeneous complex of disorders, with genetic abnormalities presenting in more than 80% of ALLs and more than 90% of AMLs. The diagnostic gold standard and classification of leukaemia involves various methods including morphology, cytochemistry, cytogenetics and molecular genetics, immunophenotyping, and molecular biology. These diagnostic methods are a prerequisite for individual treatment strategies and for the evaluation of treatment response especially considering that many distinct types of acute leukemia are known to carry predictable prognoses and warrant specific therapy. The quantification of gene expression is essential in determination of tailored therapeutic decisions. Microarray technology offers the possibility of quantifying thousands of genes in a single analysis, thus potentially becoming an essential tool for molecular classification to be used in routine leukaemia diagnostics. MLL+ leukaemia is a perfect example as to the exact correspondence between gene expression and protein expression evaluated by flow cytometry. Applying computational analysis to flow cytometry results, it is possible to distinguish the MLL+ acute leukemia from MLL- acute leukemia using as the top ranked antigen some top ranked genes described in the Microarray evaluation. Key markers discriminating different leukemia phenotypes can be identified by univariate hypothesis testing from a data set of immunophenotypic markers described by two variables, one reflecting the intensity of expression (MESF) and the other the pattern of distribution (CV). A current multi center study called Microarray Innovations in Leukemia (MILE Study) uses higher density gene chips providing nearly complete coverage of the human genome. The study which has analyzed thus far 1837 retrospective cases shows that each important leukemia subtype has a specific genetic fingerprint, meaning that different combinations of genes whose expression is linked to each subtype can be identified allowing for patient tailored therapy. Moreover, the study has achieved 97% diagnostic accuracy on samples from tested patients. Statistical analysis has shown a high concordance level between standard diagnostic procedures and those of the microarray technology--globally around 95.6%. Additionally it is possible to correctly classify some subgroups incorrectly identified using gold standard methods. Thus, from a technical viewpoint, gene expression profiling in tandem with flow cytometry should be a viable alternative to standard diagnostic approaches. Whether gene expression profiling will become a practical diagnostic alternative remains to be seen
Hepatocyte growth factor receptor c-MET is associated with FAS when activated enhances drug-induced apoptosis in pediatric B-acute lymphoblastic leukemia with TEL-AML1 translocation.
No full textExpression of c-MET, the HGF (hepatocyte growth factor) tyrosine kinase receptor, was investigated in pediatric B-acute lymphoblastic leukemia (ALL) patients. c-MET was found to be expressed in normal B cells and in B-ALL patients with the t(12;21) TEL-AML1 translocation, but it is not expressed in the most part of B-ALL without the t(12;21). We also found that c-MET, related to proliferation and protection from apoptosis, is associated with the pro-apoptotic protein FAS in TEL-AML1 B-ALL cells and in normal B lymphocytes. The possible role of this protein complex in drug-induced apoptosis was thus investigated in REH TEL-AML1 B-ALL cell line. REH cells prestimulated with HGF and treated with doxorubicin had shown a higher apoptotic rate than non-HGF-prestimulated ones (p = 0.03). REH cells stimulated with IL-3 and treated with doxorubicin did not undergo apoptosis more than nonstimulated cells, demonstrating that increased proliferation in itself is not directly related to the higher apoptotic sensitivity observed with HGF stimulation. These results indicate that c-MET activation enhances specifically FAS-mediated apoptosis in TEL-AML1 ALL cells and, considering that the c-MET/FAS complex is present only in normal B lymphocytes and in TEL-AML1 leukemias, this implies that it may have an important contribution in cellular homeostasis and in high sensitivity of TEL-AML1 ALL to chemotherapeutic regimens
Two consecutive immunophenotypic switches in a child with MLL-rearranged acute lymphoblastic leukemia
No full textAn 18-month-old girl was diagnosed with prepre-B ALL/t(4;11) leukemia, which during thetreatment and after matched bone marrow transplantation(BMT), underwent two consecutiveswitches from lymphoid to myeloid lineage andvice versa. The high expression of HOXA9 andFLT3 genes remaining genotypically stable in aleukemia throughout phenotypic switches, suggeststhat this leukemia may have originated as acommon B/myeloid progenitors
Two consecutive immunophenotypic switches in a child with MLL-rearranged acute lymphoblastic leucemia.
No full textAn 18-month-old girl was diagnosed with pre-pre-B ALL/t(4;11) leukemia, which during the treatment and after matched bone marrow transplantation (BMT), underwent two consecutive switches from lymphoid to myeloid lineage and vice versa. The high expression of HOXA9 and FLT3 genes remaining genotypically stable in a leukemia throughout phenotypic switches, suggests that this leukemia may have originated as a common B/myeloid progenitor
Identificazione di nuove anomalie geniche in LLA pediatriche a cariotipo normale o non classificate geneticamente: Analisi integrata del profilo genotipico e di espressione.
No full textNew data on robustness of gene expression signatures in leukemia: comparison of three distinct total RNA preparation procedures
No full textAbstract Background Microarray gene expression (MAGE) signatures allow insights into the transcriptional processes of leukemias and may evolve as a molecular diagnostic test. Introduction of MAGE into clinical practice of leukemia diagnosis will require comprehensive assessment of variation due to the methodologies. Here we systematically assessed the impact of three different total RNA isolation procedures on variation in expression data: method A: lysis of mononuclear cells, followed by lysate homogenization and RNA extraction; method B: organic solvent based RNA isolation, and method C: organic solvent based RNA isolation followed by purification. Results We analyzed 27 pediatric acute leukemias representing nine distinct subtypes and show that method A yields better RNA quality, was associated with more differentially expressed genes between leukemia subtypes, demonstrated the lowest degree of variation between experiments, was more reproducible, and was characterized with a higher precision in technical replicates. Unsupervised and supervised analyses grouped leukemias according to lineage and clinical features in all three methods, thus underlining the robustness of MAGE to identify leukemia specific signatures. Conclusion The signatures in the different subtypes of leukemias, regardless of the different extraction methods used, account for the biggest source of variation in the data. Lysis of mononuclear cells, followed by lysate homogenization and RNA extraction represents the optimum method for robust gene expression data and is thus recommended for obtaining robust classification results in microarray studies in acute leukemias.</p
Overall survival benefit for sequential doxorubicin-docetaxel compared with concurrent doxorubicin and docetaxel in node-positive breast cancer-8-year results of the breast international group 02-98 phase III trial
No full textBackground: In women with node-positive breast cancer, the Breast International Group (BIG) 02-98 tested the incorporation of docetaxel (Taxotere) into doxorubicin (Adriamycin)-based chemotherapy, and compared sequential and concurrent docetaxel. At 5 years, there was a trend for improved disease-free survival (DFS) with docetaxel. We present results at 8-year median follow-up and exploratory analyses within biologically defined subtypes. Methods: Patients were randomly assigned to one of four treatments: (i) sequential control: doxorubicin (A) (75 mg/m. 2) × 4 → classical cyclophosphamide, methotrexate, 5-fluorouracil (CMF); (ii) concurrent control: doxorubicin, cyclophosphamide (AC)(60/600 mg/m. 2) × 4 →CMF; (iii) sequential docetaxel: A (75 mg/m. 2) × 3 → docetaxel (T) (100 mg/m. 2) × 3 → CMF and (iv) concurrent docetaxel: AT(50/75 mg/m. 2) × 4 →CMF. The primary comparison evaluated docetaxel efficacy regardless of the schedule. Exploratory analyses were undertaken within biologically defined subtypes. Results: Two thousand eight hundred and eighty-seven patients were enrolled. After 93.4 months of median follow-up, there were 916 DFS events. For the primary comparison, there was no significant improvement in DFS from docetaxel [hazard ratio (HR) = 0.91, 95% confidence interval (CI) = 0.80-1.05, P = 0.187]. In secondary comparisons, sequential docetaxel significantly improved DFS compared with sequential control (HR = 0.81, 95% CI = 0.67-0.99, P = 0.036), and significantly improved DFS (HR = 0.84, 95% CI = 0.72-0.99, P = 0.035) and overall survival (OS) (HR = 0.79, 95% CI = 0.65-0.98, P = 0.028) compared with concurrent doxorubicin-docetaxel. Luminal-A disease had the best prognosis. HRs favored addition of sequential docetaxel in all subtypes, except luminal-A; but this observation was not statistically supported because of limited numbers. Conclusion: With further follow-up, the sequential docetaxel schedule resulted in significantly better OS than concurrent doxorubicin-docetaxel, and continued to show better DFS than sequential doxorubicin-based control. © The Author 2013. Published by Oxford University Press on behalf of the European Society for Medical Oncology. All rights reserved.SCOPUS: ar.jinfo:eu-repo/semantics/publishe
