Similarly, in mice inoculated with human EWS/FLI-1 clone #16 coexpressing KRAB/FLI-1, no tumours were observed at day 27; however, tumours formed in nine out of 10 mice inoculated with the same clone expressing mutant KRAB/FLI-1 with a mean volume of 147±32 mm3. This evidence concerns the gene EWSR1 and neoplasm.