IL2RG and Ewing sarcoma: To confirm that WNT974 inhibits expression of downstream targets of Wnt signaling and of metastasis-associated genes in vivo as well as in vitro, we implanted fragments of a Ewing sarcoma PDX, designated EWS4, as well as fragments of a xenograft derived from TC71 cells, into the pretibial space of NOD/SCID/IL-2Rγ-null (NSG) mice.