ABSTRACT
This chapter discusses the amplification of HER-2 serves as both a robust prognostic and a predictive biomarker in breast cancer. Homozygous deletion of HER-2 in mice results in embryonic lethality due to defective development of cardiac trabeculae. Amplification of the HER-2 gene was identified by Southern analysis in breast, salivary, and gastric adenocarcinoma DNA in the papers describing the cloning of the HER-2 gene. To standardize HER-2 testing for both clinical practice and future clinical trials, the American Society for Clinical Oncology and the College of American Pathologists developed guidelines for HER-2 testing for use in breast cancer patients in 2007, followed by periodical updates, the most recent one just published in 2018. HER-2 amplification or overexpression has been reported as a predictive biomarker for the response to anthracyclines and taxanes. A number of studies have reported that HER-2 amplification/overexpression is associated with response to anthracyline based chemotherapy.
