EZH2 and lymphoma: Although these have shown antitumor effects in lymphomas with enzyme-activating mutations of EZH2 [22, 23] and in ovarian cancer cells with inactivating mutations of ARID1A [24], some cancers appear resistant to EZH2 methyltransferase inhibition but sensitive to genetic depletion of EZH2, raising the possibility that EZH2 promotes tumorigenesis via methyltransferase-independent mechanisms.