Prognostic significance of survivin expression in pediatric ewing sarcoma.

Survivin is an inhibitor of apoptosis protein that inhibits caspases and blocks cell death. It is undetectable in most normal adult tissues. High survivin expression has been detected in various tumors and has been correlated with therapy resistance and poor outcome. We conducted this study to examine survivin expression in pediatric Ewing sarcoma (ES) and evaluate its role in predicting clinical outcome. Formalin-fixed paraffin-embedded tumor tissues from 108 pediatric ES patients were examined by immunostaining with survivin rabbit monoclonal antibodies. Survivin was detected in tumor tissues of 72 (66.7%) patients. High expression (≥50%) was detected in 18 (16.7%) patients. High survivin expression was shown to be a significant univariate parameter for poorer overall (OS) and event free survival (EFS) with p value 0.033, and 0.037 respectively. It was confirmed as an independent factor in multivariate analysis for OS (p: 0.041; HR: 1.97 with 95% CI of 1.03-3.79) and EFS (p: 0.049; HR: 1.86 with 95% CI of 1.00-3.46). These results suggest that high survivin expression identifies a group of patients with poor prognosis and this may help to refine risk adapted treatment; however, this needs to be confirmed in prospective studies.