Aven expression has recently been identified as an anti-apoptotic protein. In this study, Aven expression in 91 children with acute lymphoblastic leukemia (ALL) was investigated for possible correlation with clinical features at diagnosis and treatment outcome. Aven expression was found to be higher in patients >= 10 years old or < 1 year (P=0.003), and in patients with unfavorable cytogenetic abnormalities (P < 0.001). Aven expression was also significantly higher in relapsed patients in the standard-risk group. Aven overexpression was an independent poor Prognostic factor. These findings demonstrate that Aven expression can predict prognosis in childhood ALL. (c) 2005 Elsevier Ltd. All rights reserved.