Biology of acute lymphoblastic leukemia (ALL): clinical and therapeutic relevance.

Acute lymphoblastic leukemia is a heterogeneous disease comprising several clinico-biological entities. Karyotyping of leukemic cells identifies recurrent chromosome rearrangements. These are usually translocations that activate genes encoding transcription factor regulating B- or T-cell differentiation. Gene expression-array confirms the prognostic relevance of ALL subgroups identified by specific chromosomal rearrangements and isolates new subgroups. Analysis of genomic copy number changes and high throughput sequencing reveal new cryptic deletions. The challenge is now to understand how these cooperative genetic lesions interact in order to have the molecular rationales needed to select new therapeutic targets and to develop and combine inhibitors with high levels of anti-leukemic specificity. The aim of this paper is to provide some data on the biology of acute lymphoblastic leukemia which are relevant in clinical practice.