ESR1 and cancer: To comprehensively characterize tumor biopsy tissue, clinical assays were performed within the OHSU Knight Diagnostic Laboratories that are CLIA-licensed/CAP-accredited, including IHC (ER, PR, HER2, AR, and PD-L1), a targeted next-generation sequencing (NGS) panel covering 125 genes (GeneTrails© Comprehensive Solid Tumor Panel), whole transcriptomic sequencing (Illumina TruSeq RNA exome), and a multiplex protein analysis of 22 key cancer proteins and phosphoproteins (the Intracellular Signaling Protein Panel) developed on the NanoString Vantage 3DTM Solid Tumor Panel.