[Molecular biology and childhood leukemia: E2A-PBX1 and central nervous system relapse].

Acute lymphoblastic leukemia (ALL) is the most common cancer in children. The inclusion of molecular biology techniques in the diagnosis and prognostic stratification of these patients has allowed major treatment achievements in developed countries. One of the best studied gene rearrangements is E2A-PBX1, which predicts isolated central nervous system relapse in patients with ALL. However, further research on the search for new molecular markers related to prognosis of patients with childhood leukemia is required. Such studies need the integration of different disciplines, including epidemiology. Epidemiological studies are needed not only to accelerate the discovery of new molecular markers and new biological signals as to the etiology and pathophysiology of cancer, but also to evaluate the clinical impact of these findings in well-defined populations.