Recent studies have examined the implications of ESR1 mutations in metastatic breast cancer and found that ESR1 mutations predict poor response to subsequent endocrine therapy. These acquired mutations also correlate with aggressive disease and, by extension, worse prognosis. Dive further into these findings from various studies and how they might impact the way we treat patients with metastatic breast cancer with Dr. Pavani Chalasani and Dr. Marcela Mazo Canola, Assistant Professor at UT Health San Antonio’s Mays Cancer Center.