Molecular diagnostics in the treatment of childhood acute lymphoblastic leukemia

Somatically acquired genetic alterations play an important role in the path ogenesis of acute lymphoblastic leukemia. The molecular analysis of these a lterations has increased our understanding of the mechanisms of leukemogene sis. In addition, this information has led to improvements in our abilities to predict treatment response and to deliver the optimal intensity of trea tment to individual patients. For example, the prognosis for patients with acute lymphoblastic leukemia whose leukemic cells express the TEL-AML1 fusi on is favorable when they are treated on modem chemotherapy protocols, wher eas patients whose leukemic lymphoblasts contain the MLL-AF4 or the BCR-ABL fusion sometimes require allogeneic hematopoietic stem cell transplantatio n for cure. Molecular techniques are also used to detect minimal residual d isease and genetic polymorphisms that are important in optimizing drug ther apy.