PT - JOURNAL ARTICLE AU - Gebhart, Geraldine AU - Flamen, Patrick AU - De Vries, Elisabeth G.E. AU - Jhaveri, Komal AU - Wimana, Zena TI - Imaging Diagnostic and Therapeutic Targets: Human Epidermal Growth Factor Receptor 2 AID - 10.2967/jnumed.115.157941 DP - 2016 Feb 01 TA - Journal of Nuclear Medicine PG - 81S--88S VI - 57 IP - Supplement 1 4099 - http://jnm.snmjournals.org/content/57/Supplement_1/81S.short 4100 - http://jnm.snmjournals.org/content/57/Supplement_1/81S.full SO - J Nucl Med2016 Feb 01; 57 AB - Since the approval of trastuzumab, a humanized monoclonal antibody against the extracellular domain of human epidermal growth factor receptor 2 (HER2), 3 other HER2-targeting agents have gained regulatory approval: lapatinib, pertuzumab, and trastuzumab–emtansine. These agents have revolutionized the management of HER2-positive breast cancer, highlighting the concept that targeted therapies are successful when patients exhibit tumor-selective expression of a molecular target—in this case, HER2. However, response prediction and innate or acquired resistance remain serious concerns. Predictive biomarkers of a response—which could help in the selection of patients who might benefit from a selected targeted therapy—are currently lacking. Molecular imaging with anti-HER2 probes allows the noninvasive, whole-body assessment of HER2 tumor burden and has the potential to improve patient selection, optimize the dose and schedule, and rationalize assessment of the response to anti-HER2 therapies. Furthermore, unlike biopsy-based HER2 assessment, this approach can reveal inter- or intratumoral heterogeneity as well as variations in HER2 expression over time. This review summarizes the available literature and the current status of molecular imaging as a tool for the assessment of HER2 (target) expression or the prediction of an early treatment response in early and advanced HER2-positive breast cancer.