Integrated Testing Strategy for Simultaneous Detection of ESR-1 and gBRCA Mutations Via Liquid Biopsy in HR+/HER2- Metastatic Breast Cancer (mBC) Patients,

This study is testing a blood-based genetic test (liquid biopsy) that can simultaneously detect two important gene mutations — ESR1 and BRCA — in women with hormone receptor-positive, HER2-negative metastatic breast cancer. These mutations help guide which treatments work best. **You may be eligible if...** - You have confirmed estrogen and/or progesterone receptor-positive (ER+/PR+) breast cancer - Your tumor tests negative for HER2 - Your disease is advanced or metastatic - You are either about to start treatment for metastatic disease or have progressed after CDK4/6 inhibitor therapy **You may NOT be eligible if...** - You do not meet the hormone receptor positive and HER2-negative criteria - You are not in an advanced or metastatic setting Talk to your doctor to see if this trial is right for you.