Not only is PI3Kα the most common mutation seen in patients with HR+/HER2- advanced breast cancer, but it’s also associated with endocrine therapy resistance and more aggressive cancer growth. Given its prevalence and impact on outcomes, it’s important to know how and when to test for this mutation and how emerging targeted therapies might change our approach in clinical practice. Joining Dr. Charles Turck to share her insights on PI3Kα testing and targeted therapies for HR+/HER2- advanced breast cancer is Dr. Hope Rugo, Director of the Women's Cancers Program, Division Chief of Breast Medical Oncology and Professor of the Department of Medical Oncology and Therapeutics Research at City of Hope Comprehensive Cancer Center.