PAK4 and Ewing sarcoma: It should be mentioned that the antitumor activity of KPT-9274 in rhabdomyosarcoma, Ewing sarcoma, multiple myeloma, breast cancer, pancreatic ductal adenocarcinoma, colon carcinoma, and melanoma was shown to be substantially driven by PAK4 inhibition [158,161,195,196,197,198,199].