ERBB2 and breast cancer: Down‐regulation of miR‐200c has been reported in many tumours and is related to the occurrence and development of different tumours.48 Here, we first report that down‐regulation of miR‐200c is much greater in the CD44+CD24− phenotype BCSCs and suspension microspheres than in normal adherent cells of HER2+ breast cancer cells and that the most significant down‐regulation occurs in HER2+ CD44+CD24− phenotype stem cells.