The clinical efficacy of an orally administered EZH2 inhibitor, tazemetostat, is under investigation in multiple clinical trials including non-Hodgkin lymphoma (NHL), INI1/SMARCB1-negative tumors, synovial sarcoma, colorectal cancer, prostate cancer, renal cell carcinoma, ovarian cancer, and mesothelioma. This evidence concerns the gene SMARCB1 and ovarian cancer.