The subsequent breast cancer was ER+/PR+ DCIS in one patient and invasive breast cancer in the remaining nine; the invasive breast cancers were 6 HR +/HER2-, 1 HR+/HER2+ , 1 HR-/HER2-, and 1 HR+/HER2 unknown. This evidence concerns the gene ERBB2 and ductal breast carcinoma in situ.