Abstract PD3-6: ConvertHER: Evolution of genomic alterations from primary to metastatic breast cancer

Abstract Background: Changes in breast cancer receptor status over disease progression and treatment have been described to a point that could alter response to therapy. There is growing interest in delivering biomarker/genomically-based targeted therapies. We aimed to determine the concordance of genomic alterations between primary (P) and metastatic (M) breast cancer in a prospective collection study. Methods: Targeted capture and next-generation sequencing was performed on formalin-fixed paraffin-embedded (FFPE) samples, profiling 202 cancer relevant genes in 61 pairs (primary and corresponding recurrence/metastasis). Tumors were classified at baseline as [hormone receptor (HR)+/HER2-, H…