NCIt definition : A synthetic peptide derived from the protein ESW/FLI1 type 2 with potential use in
cancer immunotherapy. EWS/FLI1 is a fusion protein frequently found in patients with
Ewing's sarcoma or primitive neuroectodermal tumors (PNET). Vaccination with EF-2
peptide may stimulate the host immune response to elicit a cytotoxic T-cell response
against tumor cells that express this EWS/FL1 type 2 fusion protein.;