The current study is a case control study involving comparisons of tissue interstitial fluid from breast cancer and adjacent non-cancerous tissue as well as that from benign breast lesion and its adjacent non-diseased tissue for a distinguishable breast cancer profile. The purpose of this research is to collect fresh breast nodule/cancer and surrounding non-cancerous tissue for proteomic studies of the interstitial fluid to identify a profile distinguishing breast cancer which will also permit future research on stored interstitial fluid, blood or tissue samples. Specific markers identified from interstitial fluid study will be investigated in blood samples to develop serum markers for breast cancer diagnosis and prognosis. Additionally, we will perform both prospective and retrospective research on breast cancer involving clinical, demographic, epidemiologic information, treatment, follow-up and outcomes on breast nodule/cancer cases collected.

Inclusion Criteria:

• All subjects ≥ 18 years of age undergoing surgery for indeterminate breast nodules, breast tissue reduction, prophylactic mastectomy, and all subjects with newly diagnosed invasive breast cancer will be eligible to participate. If invasive breast cancer or suspicion of invasive breast cancer, target lesion must measure ≥ 1.0 cm on breast imaging before core biopsy.

Exclusion Criteria:

• Anyone < 18 years of age.
• Multiple synchronous primary malignancies from different organ systems.

All patients who are receiving or seeking medical care at the UPMC St. Margaret for breast cancer will be invited to participate in the research study. Patients undergoing surgery for breast nodules suspected of being cancer or high risk lesions, breast tissue reduction, or prophylactic mastectomy will also be asked to participate.