Abstract
Childhood acute leukaemias are heterogeneous group of diseases. Besides the basic classification into acute lymphoblastic leukaemias (ALL) and acute myeloid leukaemias (AML), the heterogeneity is mainly a consequence of variety of primary genetic aberrations.
These aberrations result in various biological background, variable response to treatment and variable prognosis of different leukaemia subtypes. In ALL, the most common primary aberrations with a very good prognosis are hyperdiploidy and TEL/AML1 fusion gene.
On the other hand, patients with BCR/ABL fusion or MLL gene rearrangements have poor prognosis. In AML, the AML1/ETO, CBFB/MYH11 and PML/RARA fusions are considered favourable.
Probably the most reliable prognostic factor in ALL is an early response to treatment measured as levels of minimal residual disease (MRD) in specific time-points during therapy. The role of MRD in AML is less clear; however, its monitoring becomes a part of the standard treatment protocols recently.