To investigate the role of DAX1 in the reduction in Ewing's sarcoma cell viability by K‐234 and its derivatives, we compared the EWS‐FLI1‐related gene expression after EWS‐FLI1 knockdown with FLI1‐targeting siRNA (Figure 3A) and after treatment with PTC299 (Figure 3B). Here, EWSR1 is linked to Ewing sarcoma.