Methods of prognostic factors detection in childhood acute lymphoblastic leukemia

Abstract

Acute leukemias constitute a heterogeneous group of diseases. The most common leukemia subtype in children is B-cell precursor acute lymphoblastic leukemia. Development of acute leukemias is a consequence of at least so-called two unfavorable events. The first event results in DNA damage, which in part of the cases takes place during fetal development. Therefore, in majority of patients at diagnosis, it is possible to detect particular genetic abnormalities in leukemic blasts. Flow cytometry is currently broadly used technique in laboratories dealing with hematological disorders. It enables determination of the antigen repertoire (phenotype) of leukemic cells, including the antigens associated with certain genetic abnormalities (such as prognostically favorable t(12;21) translocation or MLL gene rearrangements being a marker of poor prognosis). DNA content, which is also a prognostic factor, can be evaluated both with flow cytometry and classical cytogenetics. Other techniques, such as reverse transriptase polymerase chain reaction, fluorescent in situ hybridization, are also commonly used in diagnostic laboratories. These techniques enable detection of changes at chromosomal or single-gene level and are most frequently targeted into particular aberration, both of favorable and unfavorable prognosis. There are also more advanced, highly sensitive genetic techniques (such as multiplex ligation-dependent probe amplification, array-comparative genomic hybridization, next generation sequencing), but their application is limited for research. Particular techniques have their advantages and limitations, differ with result production time, sensitivity and specificity, cost of the analysis as well as availability