Analysis of aneuploidies by comparative genomic hybridization (CGH) in pediatric patients with acute lymphoid leukemia

Abstract

Acute Lymphoblastic Leukemia (ALL) is the most common malignancy in childhood. In general, patients with ALL present recurrent numerical or structural chromosomal aberrations that are relevant for leukemogenesis and are important for prognostic and therapeutic purposes.In the present study we propose the detection of numeric and unbalanced chromosomal aberrations by means of CGH (Comparative Genome Hybridization) and the subsequent validation by FISH (Fluorescent in situ Hybridization) with different probes in 30 bone marrow samples from pediatric ALL patients, diagnozed at the Pediatry Laboratory of the Clinical Hospital – FMRP-USP between 1998 and 2006. The criteria adopted for the inclusion of patients were the necessity of complementing the initial diagnosis, being all patients negative for the four maior structural aberrations: t(12;21), t(9;22), t(4;11) and t(1;19) (previously analysed by RT-PCR), and the lack of adequate chromosome morphology for conventional analysis.The proposed methodologies will contribute to the characterization of the disease and will provide results that might colaborate with the elucidation of the mechanisms of leukemic transformation, as well as might allow the distintion between risk groups.