Array Comparative Genomic Hybridization and Cytogenetic Analysis in Pediatric Acute Leukemias

Abstract

of microarray and conventional cytogenetics would allow for more sensitive, comprehensive, and accurate analysis of the underlying genetic profile, with concomitant improvement in prognosis and treatment, not only for pediatric all, but for neoplastic disorders in general.

Cytogenetics, Molecular Genetics and Epigenetics and Their Impact on The Management of Acute Lymphoblastic Leukemia

“…Currently, detection of cytogenetic abnormalities in the clinical arena is primarily based on: karyotyping, FISH or both [37] FISH is a technique that uses fluorescently labelled probes to locate the positions of specific DNA sequences on chromosomes [39]. FISH has expanded cytogenetics by means of: (1) identifying cryptic genetic lesions that are not shown by routine karyotyping but can affect the response to treatment, and (2) enhancing the identification of nonrandom translocations and deletions pinpointing regions which contain genes that are involved in leukemogenesis [37,38].…”

“…Thereafter, the metaphase spread cells are further analyzed using a banding technique [28]. However, conventional cytogenetic analysis of chromosomal abnormalities in patients with HMs is hampered by low mitotic index and poor quality of metaphases [37,38]. A minimum of 20 metaphase cells are usually Karyotyping on cells derived from cell cultures using banding analysis.…”

“…It uses 2 genomes: a test and a control, which are differentially labelled and competitively hybridized to metaphase chromosomes [39,40]. Array CGH has greatly increased genomic resolution over classical cytogenetic techniques, but its resolution is relatively limited compared to the more advanced molecular techniques [37,40]. The fluorescent signal intensity of the labelled test DNA relative to that of the reference DNA can then be linearly plotted across each chromosome in order to allow the identification of CNAs [39,40].…”

“…FISH has expanded cytogenetics by means of: (1) identifying cryptic genetic lesions that are not shown by routine karyotyping but can affect the response to treatment, and (2) enhancing the identification of nonrandom translocations and deletions pinpointing regions which contain genes that are involved in leukemogenesis [37,38]. Currently, FISH and other molecular approaches are used to screen for the significant abnormalities in patients with ALL [4].…”

“…Conventional cytogenetics has played a pivotal role in the detection of recurrent chromosomal rearrangements in patients with HMs thus aiding: diagnosis, prognosis and identification of the involved genes [37]. Conventional cytogenetics, which is also called chromosomal banding analysis or karyotyping, examines the patient's chromosomes in a sample of cells obtained from: peripheral blood, bone marrow (BM) aspirate or other body tissues [3].…”