Tazametostat, a potent and selective inhibitor of histone methyltransferase EZH2 (enhancer of zeste homolog 2), with some activity against EZH2 gain-of-function mutations (including Y646X and A687V, as well as EZH1), received FDA approval for use in advanced epithelioid sarcomas characterized by the loss of INI1/SMARCB1 based on positive results from the open-label, multicenter trial (Study EZH-202, NCT02601950) [73]. Here, EZH1 is linked to epithelioid sarcoma.