FLI1 and neoplasm: Individual Ewing cells within a tumor can express highly variable levels of the EWS-FLI1 fusion oncoprotein [14], and this variation in EWS-FLI1 expression can significantly alter tumor cell behavior, with cells harboring lower EWS-FLI1 levels showing increased capability to seed the lung [13], upregulate tenascin-C expression and metastasize [16].