TY - JOUR T1 - Imaging Diagnostic and Therapeutic Targets: Steroid Receptors in Breast Cancer JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 75S LP - 80S DO - 10.2967/jnumed.115.157933 VL - 57 IS - Supplement 1 AU - Amy M. Fowler AU - Amy S. Clark AU - John A. Katzenellenbogen AU - Hannah M. Linden AU - Farrokh Dehdashti Y1 - 2016/02/01 UR - http://jnm.snmjournals.org/content/57/Supplement_1/75S.abstract N2 - Estrogen receptor alpha (ERα) and progesterone receptor (PR) are important steroid hormone receptor biomarkers used to determine prognosis and to predict benefit from endocrine therapies for breast cancer patients. Receptor expression is routinely measured in biopsy specimens using immunohistochemistry, although such testing can be challenging, particularly in the setting of metastatic disease. ERα and PR can be quantitatively assayed noninvasively with PET. This approach provides the opportunity to assess receptor expression and function in real time, within the entire tumor, and across distant sites of metastatic disease. This article reviews the current evidence of ERα and PR PET imaging as predictive and early-response biomarkers for endocrine therapy. ER -