Gene expression analysis of paediatric acute lymphoblastic leukaemia. Homo sapiens

We addressed the clinical significance and mechanisms behind in vitro cellular responses to ionising radiation (IR)-induced DNA double strand breaks in 74 paediatric ALL patients. We found an apoptosis-resistant response in 36% of patients and an apoptosis-sensitive response in the remaining 64% of leukaemias. Global gene expression profiling of 11 apoptosis-resistant and 11 apoptosis-sensitive ALLs revealed abnormal up-regulation of multiple pro-survival pathways in response to IR in apoptosis-resistant leukaemias and differential post-transcriptional activation of the PI3-Akt pathway was observed in representative resistant cases. It is possible that abnormal pro-survival responses to DNA damage provide one of the mechanisms of primary resistance in ALL . Keywords: Gene expression profiling; response to irradiation Overall design: Twenty two B-precursor ALL tumours (11 responsive to IR-induced DNA damage and 11 resistant) were analysed before and 8 hours after exposure to 5 Gy IR, using the Affymetrix HG_U133A (GPL96) platform.