In vivo expression of survivin and its splice variant survivin‐2B: Impact on clinical outcome in acute myeloid leukemia

Survivin, a member of the inhibitor of apoptosis protein family, is expressed in most human cancers, but undetectable in normal differentiated adult tissue in vivo. Because of this cancer‐related expression, survivin is a promising target for cancer therapy. To determine the expression and prognostic role of survivin in acute myeloid leukemia (AML), we investigated the mRNA expression pattern of survivin and of the splice variants survivin‐2B and survivin‐ΔEx3 in adult (n = 74) and children (n = 31) with de novo AML using RT‐PCR. Survivin was the predominant transcript variant in AML cells, whereas significantly lower levels of survivin‐2B and survivin‐ΔEx3 were observed (p ≤ 0.0001). Neither expression of survivin nor of any splice variant correlated with maturation stage (FAB subtypes, immunophenotype) or cytogenetic risk groups. For AML cases treated according to AMLCG92 (adult) and AML‐BFM93 (children) protocols, respectively, expression patterns were correlated with clinical data: In adult AML (n = 51), low expression of survivin‐2B correlated with a better overall survival (p = 0.05; mean survival time 19 months vs. 9 months) and a better eventfree survival (p ≤ 0.01; 27 months vs. 10 months). In childhood AML (n = 31), high survivin‐ΔEx3 expression was associated with a shorter overall survival (p ≤ 0.05; 24 months vs. 43 months). We conclude that certain survivin splice variants have potential prognostic impact for long‐term therapy outcome in adult as well as childhood de novo AML. © 2006 Wiley‐Liss, Inc.