FLI1 and neoplasm: In contrast, salEPv>Gal4-driven expression is sufficient for pEWS-FLI1 to cause wing imaginal disc tumours, and nub>Gal4-driven expression of pEWS-FLI1+Gal80@25 yields even larger tumours in the rare escapers (figure 3b, rows 2 and 3).