1,721,414 research outputs found
Oncogenes and cancer
No full textThe identification of oncogenes involved in the initiation and progression of tumors has generated targets for the development of new anticancer drugs. Several new drugs, small molecules, and monoclonal antibodies directly affecting oncogene products have been developed, and more will follow. Considerable progress has been made in producing small molecules capable of inhibiting the enzymatic activity of ABL, KIT, EGFR, and ERBB2. For cases in which the oncogene products are not enzymes, it has been much more difficult to develop new agents. The advantage of targeted therapy is the dependency of cancer cells on the oncogene product for growth and survival. Thus, cancer cells are more sensitive to the treatment than are normal cells. All targets, however, are not equivalent. It is possible to foresee the development of multiple drugs that have multiple targets involved in the development of cancer. The discovery of the involvement of microRNAs in the initiation and progression of human cancer may provide additional targets for anticancer treatments. Copyright © 2008 Massachusetts Medical Society
Genomics of chronic lymphocytic leukemia microRNAs as new players with clinical significance
No full textChronic lymphocytic leukemia (CLL), the most frequent leukemia in adults in the Western world, is characterized by predominantly nondividing malignant CD5+ B cells overexpressing the anti-apoptotic Bcl2 protein. Significant familial aggregation with largely unknown mode of inheritance has been demonstrated. Until recently little else was known regarding the events leading to CLL initiation and progression. New findings support the view that CLL is a genetic disease where the main alterations occur at the level of transcriptional/post-transcriptional regulation of the malignant cells genome because of deregulations of a new class of genes named microRNAs (miRNAs). miRNA genes miR-15a and miR-16-1, located at 13q14.3, are frequently deleted and/or downregulated in patients with B-cell CLL. Both microRNAs negatively regulate Bcl2 at a post-transcriptional level and this repression is enough to induce apoptosis. Therefore, miR-15 and miR-16 are natural antisense Bcl2 interactors that could be used for therapy of Bcl2-overexpressing tumors. Furthermore, microRNA expression profiles can distinguish normal B cells from malignant B cells in CLL. A unique microRNA signature is associated with prognostic factors such as mutations in the immunoglobulin heavy-chain variable-region gene (IgV(H)) or high expression of the 70-kd zeta-associated protein (ZAP-70+) and disease progression in CLL. Mutations in miRNA transcripts are frequent, some of them germ-line, and may have functional importance and may predispose to CLL and to a spectrum of associated malignancies
MicroRNAs in normal and malignant hematopoiesis
No full textPURPOSE OF REVIEW: The discovery of a novel class of gene regulators, named microRNAs, has changed the landscape of human genetics. In hematopoiesis, recent work has improved our understanding of the role of microRNAs in hematopoietic differentiation and leukemogenesis. RECENT FINDINGS: Using animal models engineered to overexpress miR-150, miR-17 approximately 92 and miR-155 or to be deficient for miR-223, miR-155 and miR-17 approximately 92 expression, several groups have now shown that miRNAs are critical for B-lymphocyte development (miR-150 and miR-17 approximately 92), granulopoiesis (miR-223), immune function (miR-155) and B-lymphoproliferative disorders (miR-155 and miR-17 approximately 92). Distinctive miRNA signatures have been described in association with cytogenetics and outcome in acute myeloid leukemia. SUMMARY: There is now strong evidence that miRNAs modulate not only hematopoietic differentiation and proliferation but also activity of hematopoietic cells, in particular those related to immune function. Extensive miRNA deregulation has been observed in leukemias and lymphomas and mechanistic studies support a role for miRNAs in the pathogenesis of these disorders
Prognostic microRNA/mRNA signature from the integrated analysis of patients with invasive breast cancer.
No full textThe optimal management of breast cancer (BC) presents challenges due to the heterogeneous molecular classification of the disease. We performed survival analysis on a cohort of 466 patients with primary invasive ductal carcinoma (IDC), the most frequent type of BC, by integrating mRNA, microRNA (miRNA), and DNA methylation next-generation sequencing data from The Cancer Genome Atlas (TCGA). Expression data from eight other BC cohorts were used for validation. The prognostic value of the resulting miRNA/mRNA signature was compared with that of other prognostic BC signatures. Thirty mRNAs and seven miRNAs were associated with overall survival across different clinical and molecular subclasses of a 466-patient IDC cohort from TCGA. The prognostic RNAs included PIK3CA, one of the two most frequently mutated genes in IDC, and miRNAs such as hsa-miR-328, hsa-miR-484, and hsa-miR-874. The area under the curve of the receiver-operator characteristic for the IDC risk predictor in the TCGA cohort was 0.74 at 60 mo of overall survival (P < 0.001). Most relevant for clinical application, the integrated signature had the highest prognostic value in early stage I and II tumors (receiver-operator characteristic area under the curve = 0.77, P value < 0.001). The genes in the RNA risk predictor had an independent prognostic value compared with the clinical covariates, as shown by multivariate analysis. The integrated RNA signature was successfully validated on eight BC cohorts, comprising a total of 2,399 patients, and it had superior performance for risk stratification with respect to other RNA predictors, including the mRNAs used in MammaPrint and Oncotype DX assays
[A new synthetic anti-androgen, 17 alpha beta-dimethyl-18-nor-androsta-4,13-dien-11 alpha olo-3one; trials in humans].
No full textGenomic organization of the ATM locus involved in ataxia-telangiectasia
No full textThe ATM gene, involved in the genetic disorder ataxia-telangiectasia (AT), has been identified recently. This gene is suspected to predispose to malignancy and is located in a chromosomal region that we have recently found deleted in 50 to 60% of breast and lung carcinomas. Because of its location and its function, the ATM gene is a strong candidate tumor suppressor or modifier gene of chromosome region 11q23. In this study, we define its genomic structure. The aim was to establish the basis for the development of mutation scanning methods based on DNA instead of RNA. We found that the gene spans a region of approximately 70-80 kb and is composed of 37 exons, ranging in size from 64 to 324 bp. Nucleotide sequences of all exon/intron boundaries were determined. With this information, it will be possible to develop simple genetic tests for the identification of homozygotes and heterozygotes, as well as determine whether the gene is involved in the pathogenesis of breast and other carcinomas
miRNAs, cancer, and stem cell division
No full textMicroRNAs (miRNAs) are known to regulate the expression of genes involved in the control of development, proliferation, apoptosis, and the stress response. As a cluster of recent Nature papers now show, altered expression of specific miRNA genes contributes to the initiation and progression of cancer
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