PRDM9 and breast cancer: Expression profiles of hormone receptors (ER, PR), and Her-2/neu are closely associated with BC, being therefore used for prognosis and therapeutic response predictions.4 Some studies have shown that along with these parameters, Enhancer of Zeste Homolog 2 (EZH2) and CD44, molecular markers with cancer stem characteristics, have an important role in the prognosis of BC.6 EZH2 is the catalytic subunit of Polycomb repressive complex 2 (PRC2), which is a highly conserved histone methyltransferase that targets lysine-27 of histone H3.