EZH2 and triple-negative breast carcinoma: Enhancer of zeste homolog 2 (EZH2), the catalytic subunit of the polycomb repressive complex 2 (PRC2), which mediates transcriptional repression through histone H3 lysine 27 trimethylation (H3K27me3), is highly expressed in aggressive triple-negative breast cancer (TNBC).