Given the preliminary results of the phase 1/2 study showing activity of tazemetostat in INI1 deficient tumours (NCT02601950) [87], a phase 2 trial (NCT02601950) is currently ongoing to assess the activity of the drug in this group of solid cancers, including INI1-deficient epithelioid sarcoma and SS marked by the SS18-SSX1 translocation. This evidence concerns the gene SS18 and synovial sarcoma.