As a histone methyltransferase that functions as the catalytic subunit of the polycomb repressive complex 2 (PRC2), EZH2 inhibits the functions of Th1 chemokine C-X-C motif chemokine ligand 9 (CXCL9) and C-X-C motif chemokine ligand 10 (CXCL10) and exerts a carcinogenic effect in a variety of tumors, including breast cancer, ovarian cancer, prostate cancer, non-Hodgkin lymphoma (NHL), and T-cell ALL (156–159). The gene discussed is CXCL10; the disease is ovarian carcinoma.