Previous studies revealed that EZH2 was up-regulated in DCIS and even morphologically normal breast epithelial cells from patients with increased risk of breast carcinoma [26, 27], and EZH2 was reported as a molecular marker for identifying a precancerous state in morphologically normal breast, but these studies did not reveal the relationship of EZH2 and triple-negative breast carcinoma and its in situ components [26, 27]. Here, EZH2 is linked to ductal breast carcinoma in situ.