Overcoming resistance to conventional drugs in Ewing’s sarcoma and identification of molecular predictors of outcome.

The improvement of Ewing's sarcoma (EWS) therapy is currently linked to find strategies to select patients with poor and good prognosis at diagnosis and to generate modified treatment regimens. In this study, we analyze the molecular factors governing EWS response to chemotherapy in order to identify genetic signatures that may be used for risk-adapted therapy. Keywords: Gene Expression Analysis. Affimetrix platform was used for profiling 30 primary tumors of patients that were classified according to event-free survival and 7 metastasis. NED: no evidence of diseaase (event-free); REL: relapse; MET: metastasis. For selected genes, Real-Time PCR was applied in 42 EWS primary tumors as validation assay. MTT test was used to evaluate in vitro drug sensitivity.