Acute lymphoblastic leukemia

Abstract

Acute lymphoblastic leukemia (ALL) comprises a heterogeneous group of disorders which originate from various important genetic lesions in B and T progenitor cells, including mutations that lead to stage-specific developmental arrest and those that impart the capacity for unlimited self-renewal, resulting in clonal expansion of immature progenitor cells (Pui et al. Lancet 371:1030-43, 2008; Pui et al. Blood 120:1165-74, 2012; Morgolin et al. 2011). Different B-and T-cell ALLs can be recognized according to immunologic and molecular criteria (Pui et al. Blood 82:343-62, 1993; Yeoh et al. Cancer Cell 1:133-43, 2002; Pui et al. J Clin Oncol 29:551-65, 2011). The identification of the molecular events underlying the process of leukemia transformation has provided not only important biological information but also clinically significant genetic markers for the identification of prognostically relevant ALL subgroups and for the molecular monitoring of minimal residual disease (MRD). For ALL, immunoglobulin (IG) and T-cell receptor (TCR) gene rearrangement studies are used as markers of clonality and for MRD detection. In addition, the identification of different genetic variations is used to define different ALL subgroups and to refine treatment protocols tailored to the risk of relapse.