In two previous studies, we found that human epidermal growth factor receptor 2 (HER2)-enriched high-grade DCIS was a high-risk subtype because it was strongly linked to having invasive components (8) and low progesterone receptor (PR) levels, correlated with HER2 overexpression and the presence of invasive components (9). Here, ERBB2 is linked to ductal breast carcinoma in situ.