Genetically Engineered Mouse Model in Ewing Sarcoma.

Modeling Ewing sarcoma is challenging, since overexpression of EWSR1::FLI1 induces apoptosis and is not sufficient for tumor induction. It is therefore important to obtain the cell-of-origin of Ewing sarcoma that is tolerant of EWSR1::FLI1 expression. Here we describe the generation of the EWSR1::FLI1-expressing mouse model for Ewing sarcoma by selecting embryonic chondrogenic progenitor, eSZ cells that contain Ewing sarcoma precursors.