The multiple fusion partners of EWSR1 gene associated with Ewing sarcoma are FLI1, ERG, ETV1, ETV4, FEV and ZSG. Interphase FISH is rapid and can serve as a first line assay to detect the gene rearrangement in the routine pathological diagnostic workup of bone and soft tissue tumours. The gene discussed is ERG; the disease is Ewing sarcoma.