Correlation of Molecular Markers With Response to Therapy and Breast Cancer Behavior

This study is taking biopsy (small tissue) samples from breast cancer tumors at different points during treatment to study how cancer cells change over time in response to therapy. **You may be eligible if...** - You are 18 or older with suspected or known breast cancer (early or metastatic/spreading) - Your tumor can be safely biopsied as determined by your doctor - You are in reasonably good health (ECOG performance status 0–2) - You have adequate blood counts if a biopsy of a vital organ (lung, liver) is needed **You may NOT be eligible if...** - You have a serious medical or psychiatric condition that makes participation unsafe or inappropriate - You have dementia or a condition that prevents you from giving informed consent - You have a serious allergy to local anesthetics (such as lidocaine) - You are pregnant - You have a heart condition that makes biopsy unsafe - You have received bevacizumab or similar anti-angiogenesis drugs less than 6 weeks ago (for vital organ biopsies) or less than 2 weeks ago (for breast/skin biopsies) Talk to your doctor to see if this trial is right for you.