Chapter 2 Acute Leukemia

Acute leukemia (AL) is the commonest malignancy in children less than 15 years of age [ 1 ] . Approximately 3,000 new cases of AL occur annually in the U.S.A., of which 80% are acute lymphoblastic leukemia (ALL). The 5-year survival rates for childhood AL, and especially ALL has dramatically improved from 61% in 1975– 1978 to 89% in 1999–2002 [ 2– 4 ] . The remarkable success story of pediatric ALL is attributed to the exponential increase in knowledge of the molecular mechanisms of the disease and the impact of well-designed clinical trials adapted to risk-strati fi ed subgroups based on prognostic indicators, including evaluation of early response to the treatment (minimal residual disease detection). This has been accomplished by genomic studies employing a host of modern techniques, for example, conventional cytogenetics, fl uorescent in situ hybridization (FISH), DNA and gene expression arrays, and proteomics. Many of these methodologies have moved from the research bench to clinical molecular diagnostics allowing their routine use in the diagnosis, classi fi cation, prognostication, and follow-up of acute leukemia. In this chapter we describe the clinical features and associated genetic abnormalities of AL and discuss their impact on clinical management of AL. The subsequent chapter on AL in this volume describes molecular techniques routinely used in the diagnosis and prognostication of acute leukemia.