EWSR1 and Ewing sarcoma: Genetically, Ewing’s sarcoma is characterised by fusion of the EWSR1 genes, typically with the ETS gene, such as FLI1 in 90% or ERG in 5%; mergers with rarer partners are FEV, ETV1, and ETV4, but detection of these mergers alone is not diagnostic [18,48,49].