BMI-1 expression inversely correlates with differentiation but not clinical outcome or CDKN2a expression in Ewing sarcoma family of tumors.

摘要

Ewing sarcoma family tumors (ESFT) are highly undifferentiated bone and soft tissue tumors that primarily affect children. Metastatic disease at diagnosis portends a worse prognosis and remains the only reliable predictor of outcome. The polycomb protein BMI-1 is associated with worse clinical outcome in some human cancers. This study evaluates the clinical and biologic significance of BMI-1 expression in ESFT.;Using immunohistochemical analysis, 80% of ESFT were found to robustly express BMI-1 in all tumor cells, while 15% lacked BMI-1 expression. Analysis of 79 tumors revealed no association between BMI-1 and clinical presentation, outcome, loss of p16 or mutation of p53. Significantly, however, BMI-1 levels were highly inversely correlated with markers of neural crest differentiation. Together these findings demonstrate that ESFT cells nearly universally express BMI-1 and suggest that high-level expression of BMI-1 underlies the highly undifferentiated phenotype that characterizes this tumor family.