The effects of cytogenetic factors on the survival of a child with ALL. H. Cangul¹, T. Yakut¹, T. Gulten¹, A. Meral², B. Baytan². 1) Department of Medical Genetics Uludag University School of Medicine, Bursa, Turkey; 2) Department of Child Hematology, Uludag University School of Medicine, Bursa, Turkey.
   Acute lymphoblastic leukemia (ALL) is the most common form of childhood leukemias and constitutes 80% of all leukemia cases under the age of 15. Cases with ALL respond well to therapy. The qualitative and quantitative detection of specific chromosomal abnormalities has an important merit as a prognostic marker besides age, leukocyte count, and immunophenotyping in estimating prognosis, assessing the clinical status of the cases before and after therapy, and in monitoring minimal residual disease. The rearrangements t(9;22) and t(4;11), and hypodiploidies indicate poor prognosis whereas hyperdiploidy favors a good one. The case presented here was diagnosed at 13 months of age and stratified into the high-risk group based on age, leukocyte count, and immunophenotyping. In molecular cytogenetic analysis by FISH, whereas the translocations of t(9;22), t(4;11), t(15;17), and t(8;21) were negative, the copy numbers of chromosomes 8 and 21 were increased. The case was treated according to standard protocols but died within one and a half years. Although hyperdiploidy suggests a good prognosis, the findings of our case show that potential good prognostic effects of trisomies 8 and 21 failed to counter-balance the poor prognosis in a patient clinically stratified into the high-risk group. This provokes further studies with large series to evaluate the relationship between prognosis and cytogenetic characteristics in leukemia patients.