XIAP expression is post-transcriptionally upregulated in childhood ALL and is associated with glucocorticoid response in T-cell ALL

Background Resistance to glucocorticoid induced apoptosis is one of the major risk factors for relapse and poor outcome in childhood acute lymphoblastic leukemia (ALL). Overexpression of X‐linked inhibitor of apoptosis protein (XIAP) has been shown to be associated with chemotherapy resistance in several malignancies. Procedure XIAP protein and mRNA expression were determined in leukemic blasts of 51 childhood ALL patients and normal bone marrow mononuclear cells. XIAP expression was correlated with glucocorticoid response and outcome. Results XIAP protein but not mRNA expression was found to be highly increased in childhood ALL compared to control bone marrow mononuclear cells (MNC) (median: 3.5 vs. 0.14 ng/105 MNC, P