HER2 Vaccine for Locally Advanced Breast Cancer

This study is testing a vaccine targeting HER2 — a protein overexpressed in some breast cancers — for patients with HER2-positive breast cancer that is at high risk of returning. The vaccine is designed to train the immune system to recognize and attack cancer cells. **You may be eligible if...** - You are 18 years or older - You have been diagnosed with HER2-positive breast cancer (confirmed by lab testing) - Your cancer is considered high-risk — either it is locally recurrent, stage III, inflammatory, or there was cancer remaining after chemotherapy before surgery - You have already received at least some standard treatment including trastuzumab (Herceptin) **You may NOT be eligible if...** - Your cancer has spread to the brain or spinal fluid - You have active autoimmune disease - You have HIV, active hepatitis B or C, or serious uncontrolled infections - You are pregnant or breastfeeding Talk to your doctor to see if this trial is right for you.