HER2-positive breast cancers may have potential chemosensitivity in combination with trastuzumab, in the neoadjuvant treatment.221 The trastuzumab treatment in neoadjuvant therapy provides significant clinical benefits and reduces the rate of distant metastasis.222 The HER2 gene amplification is shown to be related to the growth and survival of breast cancer stem cells, to some extent.223,224. This evidence concerns the gene ERBB2 and breast cancer.