ESR1 and breast carcinoma: The most common IHC assay was for breast cancer biomarkers: estrogen receptor (100%); progesterone (92.5%); and Her2neu (87.5%). The most common treatments frequently or always available for patients with breast cancer were surgery (64.2%), chemotherapy (45.3%), endocrine therapy (34.8%), radiation (15%), and Her2neu directed therapy (< 14%).