HER-2 gene (proto-oncogene human epidermal growth factor receptor 2 gene), i.e. C-erbB-2 gene, has tyrosine kinase activity and is an important prognostic factor for breast cancer. HER-2(+) means that there is overexpression or amplification of HER-2 gene. The detection methods are immunohistochemistry, Fish, etc. Currently, there are drugs that target the inactivation of this gene, such as trastuzumab, patuximab and pirotonib.