Gain-of-function mutations that constitutively activate EZH2 (especially missense mutations of tyrosine 641) are highly prevalent in non–Hodgkin lymphoma–type (NHL-type) B cell lymphomas of germinal center origin (13), and tazemetostat was specifically indicated for adult patients with FL with an identified EZH2 mutation based on clinical trial results. Here, EZH2 is linked to B-cell non-Hodgkin lymphoma.