In the present study, we compared the effect of OA on proliferation and migration in two human DCIS cell lines, MCF10DCIS.COM (estrogen receptor; ER, progesterone receptor; PR and HER2-negative) and SUM-225 (HER2 overexpressed) cells, and investigated the different action of OA on the cellular behavior of the distinct subpopulations (ALDHhigh and ALDHlow) isolated from MCF10DCIS.COM cells. This evidence concerns the gene ERBB2 and ductal breast carcinoma in situ.