Breast Cancer Proteomics and Molecular Heterogeneity

This study collects tumor tissue and blood samples from people with breast cancer — whether newly diagnosed, recurrent, or metastatic (spread) — to study the molecular diversity of breast tumors and identify patterns that predict treatment response. **You may be eligible if...** - You are 18 or older and have been diagnosed with primary breast cancer, recurrent breast cancer, or newly diagnosed stage 4 (metastatic) breast cancer - You are scheduled for surgery or a biopsy to remove or sample tumor tissue - You are able to provide informed consent **You may NOT be eligible if...** - There are no additional specific exclusion criteria listed beyond being unable to give consent Talk to your doctor to see if this trial is right for you.