BRE-04: Window of Opportunity Trial of Preoperative Low Dose Azacitidine in High-Risk Early Stage Breast Cancer

This trial is testing whether a low dose of a drug called azacitidine (which can reactivate silenced genes) given before surgery can improve the immune response to breast cancer. This is a 'window of opportunity' study, meaning the drug is given for a brief period before the tumor is surgically removed so researchers can study its effects on the tumor. **You may be eligible if...** - You are 18 or older with a confirmed diagnosis of invasive breast cancer (early stage, not yet spread) - Your cancer is one of: triple-negative breast cancer (TNBC), HER2-positive, or estrogen receptor-positive with high-risk features (node-positive, HER2-positive, poor prognosis profile, or PR-negative) - You have not yet received any treatment for this breast cancer diagnosis - You have adequate blood counts and organ function - You are not pregnant or breastfeeding **You may NOT be eligible if...** - You have already received any chemotherapy, immunotherapy, or radiation for this breast cancer - You have breast implants - You have an active serious infection, uncontrolled HIV/AIDS, or active viral hepatitis - You are pregnant or nursing Talk to your doctor to see if this trial is right for you.