الفهرس 
ACUTE LEUKEMIAOnly 14 pages are availabe for public view
 |  | from | 203 |  |  |
| | | from | 203 | | |
Abstract
Acute leukemia is a malignant disease characterized by a clonal proliferation of abnormal leukemic (blast) cells, principally in the marrow and impaired production of normal blood cells. It is broadly subdivided into myeloid and lymphoblastic categories based on the cell of origin. For classification of leukemic blast cells in acute leukemia; morphology, cytochemistry, immunopheno¬typing and molecular cytogenetic studies are required.
Acute leukemia is a multistep process involving the accumula¬tion of genetic changes in somatic cell. These genetic changes then consist of the activation of cooperating oncogenes and the inactivation of tumor suppressor genes, which both appear necessary for leukomogenesis.
Oncogenes are altered versions of normal cellular genes called proto-oncogenes. Proto-oncogenes are a diverse group of genes involved in the regu¬lation of cell growth. The functions of proto¬oncogenes include growth factors, growth factor receptors, signal transducers, transcription fac¬tors, and regulators of programmed cell death. Proto-oncogenes may be activated by mutation, chromosomal rearrangement, or gene amplifica¬tion, the identification of oncogene abnormalities has provided tools for the molecular diagnosis and monitoring of cancer. Most important, oncogenes represent potential tar¬gets for new types of cancer therapies.
Tumor suppressor genes, which also participate in the regulation of normal cell growth, are usu¬ally inactivated by point mutations or truncation of their protein sequence coupled with the loss of the normal allele.
Molecular cytogenetic techniques are used for the diagnosis of leukemia, Classification as well as prognosis and analysis of the mechanisms of resistance to antileukemic therapy. Chromosomal studies include: banding techniques, FISH, in addition to flow cytometry. Molecular techniques are also important and give an overview idea about the DNA such as the southern blot analysis, polymerase chain reaction.
Great efforts have been made to define uniform prognostic criteria for AL. Prognostic features play a critical role in directing therapy and treatment, this area of investigation changes rapidly.
With full knowledge of the chromosomal aberrations in hand, we can improve cancer diagnosis through more and more sophisticated molecular classification, enhance the selection of therapeutic targets for drug development, promote the development of faster and more efficient clinical trials using agents targeted to specific genomic abnormalities, and create markers for early detection and prevention.
It is more than a hope that a new generation of chemothera¬peutic agents directed at specific oncogene targets will be developed. The goal of these new drugs will be to kill cancer cells selectively while sparing nor¬mal cells.