We examined five EWS tumor sample pairs, consisting of samples collected before and after chemotherapy using a VDC-IE (vincristine, doxorubicin, cyclophosphamide, ifosfamide, and etoposide) or VAIA (vincristine, actinomycin D, ifosfamide, and doxorubicin) regimen. This evidence concerns the gene EWSR1 and neoplasm.