EWSR1 and Ewing sarcoma: These include chromosome 11, resulting in the EWSR1::FLI1 chimera, which is pathognomonic for Ewing sarcoma, as well as q13 segments of chromosome 12 that, when fused to the q12.2 locus of chromosome 22, result in the genesis of another chimeric gene, the EWSR1::ATF1 [13,14,15].