Molecular and cytogenetic evaluation of pediatric leukemias

Objective: This study was conducted to determine the rate of genetic changes that may be a risk factor in the treatment of our leukemia patients. Method The study was conducted prospectively in 39 patients who were followed in department of pediatric hematology. Bone marrow or peripheral blood samples (with more than 30% blast invasion) evaluated for cytogenetics before the leukemia treatment. TEL/AML1 probe was applied to 18 of 20 acute lymphoblastic leukemia (ALL) patients and mixed lineage leukemia (MLL) probe was applied to 3 patients with infantile leukemia diagnosis. Results: Chromosomal aberration was detected in 8(40%) of 20 patients with ALL diagnosis and in 6(60%) of 10 patients with acute myeloid leukemia (AML) diagnosis. Translocation involving the MLL gene region was detected cytogenetically in two of three patients with infantile leukemia while in the other patient, it was shown by Fluorescence In Situ Hybridization analysis. TEL/AML1 fusion was detected in 5(27.7%) of 18 patients with a diagnosis of B-precursor ALL. Amplification of the AML1 gene was defined in 7(38.8%) of 18 pediatric ALL patients. Conclusion: Cytogenetic investigations should be continued in leukemia patients. The rate of chromosomal aberrations in ALL and AML patients was consistent with the literature. The rate of TEL/AML1 gene fusion which is a good prognostic factor in ALL patients, was consistent with the literature.