In contrast to reports on EWSR1:PATZ1-fused sarcoma [3, 7, 27, 52], there was no appreciable or distinguishing expression of CD99 or desmin (Supplementary Table 2; Supplementary Fig. 3, online resource) or other muscular markers such as MYOD1, myogenin, CALD1, or SOX10 in the present series (not shown). Here, EWSR1 is linked to sarcoma.