The diversity of soft tissue tumours with EWSR1 gene rearrangements: a review.

Many soft tissue sarcomas have chromosomal translocations with resultant formation of new fusion genes. Among the genes that can be rearranged, the EWSR1 gene has been identified as a partner in a wide variety of clinically and pathologically diverse sarcomas as well as some non-mesenchymal tumours. The former include Ewing sarcoma and similar (Ewing-like) small round cell sarcomas, desmoplastic small round cell tumour, myxoid liposarcoma, extraskeletal myxoid chondrosarcoma, angiomatoid fibrous histiocytoma, clear cell sarcoma of soft tissue and clear cell sarcoma-like tumours of the gastrointestinal tract, primary pulmonary myxoid sarcoma, extrasalivary myoepithelial tumours and sporadic examples of low-grade fibromyxoid sarcoma, sclerosing epithelioid fibrosarcoma and mesothelioma. EWSR1 is a 'promiscuous' gene that can fuse with many different partner genes, but sometimes this results in phenotypically identical tumours. EWSR1 can, conversely, partner with the same genes in morphologically and behaviourally different neoplasms. This paper reviews the diversity of the several soft tissue tumour types that are associated with rearrangement of the EWSR1 gene.