ER-positive breast carcinoma with a low proliferative index showed the lowest percentage of EZH2 overexpression, whereas triple-negative breast carcinoma showed the highest percentage of EZH2 overexpression, 18.5 % (10/54) versus 90.9 % (50/55), (Chi-square, p < 0.001). This evidence concerns the gene EZH2 and triple-negative breast carcinoma.