Haematopoietic stem cell transplantation (HSCT) in the therapy of paediatric acute lymphoblastic leukaemia (ALL) is reserved for the patients who have failed conventional chemotherapy. A high-risk disease (eg T-cell immunophe-notype, presence of t(9;22) or t(4;11)), poor response to the initial treatment and relapse are the most common indications for HSCT.
Despite the intensity of HSCT treatment, relapse of the disease occurs in approximately 40% of patients. The recurrence of the disease and transplant-related mortality (TRM) are the major factors with a negative influence on the outcome after HSCT in paediatric patients with ALL.
A high emphasis is placed on searching for prognostic markers to distinguish the patients who will benefit from HSCT from those who will profit from different therapeutic modalities or further modifications of HSCT.