We predicted that EWS-FLI1 ‘low’ cells would be more susceptible to T-cell mediated killing compared to EWS-FLI1 ‘high’ cells given that: 1) EWS-FLI1 ‘low’ cells demonstrate greater basal and IFN-γ inducible ICAM-1 expression, 2) tumor cell ICAM-1 has been shown to enhance T-cell activation in multiple cancers [19–21] and 3) blocking tumor ICAM-1 reduces T-cell mediated Ewing tumor cell apoptosis in our system. This evidence concerns the gene FLI1 and Ewing sarcoma.