EZH2 and ovarian cancer: Enhancer of zeste homolog 2 (EZH2) is a catalytic subunit of polycomb repressive complex 2 (PRC2), which represses genes involved in tumorigenesis (e.g., hMLH1, ARHI and RASSF1A in ovarian cancer) via methylation of lysine 27 of histone 3 (H3K27) [11].