Childhood Acute lymphoblastic leukemia (ALL) has experienced a dramatic improvement in survival rates over the past 40 years. At this time, the likelihood of cure is greater than 70%. Despite such success, relapse still occurs in 25–30% of children. The major cause of treatment failure is intrinsic or acquired drug resistance. It has been reported that stromal cells of the bone marrow (BMSC) provide a sanctuary in which subpopulations of leukaemia cells can evade chemotherapy-induced death and acquire a drug-resistant phenotype. This explains why, when ALL cell lines are cultured on human BMSC, the apoptotic effect of chemotherapic drugs is strongly inhibited. The mechanisms of BMSC-mediated protection involve a complex interplay among stroma-derived factors, in particular the SDF-1a and the chemokine receptor CXCR4. For these reasons, CXCR4-targeting compounds are nowadays considered potential therapeutic tools in ALL (
Disclosures: No relevant conflicts of interest to declare.
This work was supported by “Associazione Noi per Voi”, Firenze and Associazione Italiana per la Ricerca sul Cancro (AIRC).