ERBB2 and ductal breast carcinoma in situ: We found that in the HER2+ group, DCIS-Mi patients were younger than DCIS, but the difference was not statistically significant (P = 0.218).It is valuable that DCIS-Mi patients are associated with larger tumor size (P < 0.001), HR negativity (P = 0.015), higher Ki-67 index (P = 0.003) and higher TILs density (P = 0.002).There are also differences in surgical options between the two groups of BC patients.