Adjuvant endocrine therapy as well as other forms of targeted therapy such as HER2 inhibitors and antiangiogenic agents reduce the risk of recurrence and improve survival among women with hormone receptor positive breast cancer. However, a significant percentage of women who receive targeted therapy as adjuvant or metastatic treatment do not benefit from this therapy, while a number of women who initially respond will eventually develop disease progression and relapse while on therapy. The observed variability in treatment response to targeted breast cancer treatment could be partly explained by pharmacogenomics. This paper reviews evidence on the role of pharmacogenomics of breast targeted therapy focusing on the clinical relevance of genetic variation. In particular, this article reviews the role of pharmacogenomics of tamoxifen, aromatase inhibitors, HER-2 inhibitors and anti-angiogenic agents. In addition, recent patents in the field are presented that provide promising steps in the field of personalized treatment of breast cancer, although future studies are needed for determining the clinical benefit of the proposed inventions. Finally, we present a testable hypothesis to aide the search for biologically meaningful genetic variation Specifically, we suggest the publication of negative results in the field of pharmacogenomics and pharmacoproteomics, will benefit future research in the field.
Keywords: Breast cancer, targeted therapy, pharmacogenomics, tamoxifen, aromatase inhibitors, anastrozole, exemestane, estrogen receptors, rastuzumab, anti-angiogenetic agents, bevacizumab, CYP2D6 polymorphisms., VEGFA