In this study, EWS/FLI-1 exon combinations 7/6 (type I) predominated over 7/5 (type II) in localised ET (14 versus 1) and were more abundant in tumours affecting the long bones (9 versus 0), whereas in central axis tumours and metastatic disease there was only little difference in the frequency of the two types. Here, EWSR1 is linked to metastatic neoplasm.