Predicting Response and Toxicity in Patients Receiving Paclitaxel and Avastin for Breast Cancer

Inclusion Criteria:

* Histologically or cytologically confirmed adenocarcinoma of the breast with measurable locally recurrent, locally advanced (that is not amenable to resection with curative intent), or metastatic disease.
* Patients must consent to have a biopsy performed to obtain fresh tissue or be able to identify a FFPE tissue block in which tissue samples can be obtained to complete the testing for this study.
* Planned chemotherapy regimen of paclitaxel and Avastin for the treatment of metastatic breast cancer.
* Females age \> 18 years
* Written informed consent and HIPAA authorization for release of personal health information.

Exclusion Criteria:

* Patients must not have had chemotherapy for locally recurrent or metastatic breast cancer.
* Hormonal therapy for locally recurrent or metastatic disease must have been discontinued at least 2 weeks prior to study entry.
* Patients must not have had adjuvant or neoadjuvant taxane therapy within 12 months prior to study entry.
* Breast cancer overexpressing HER-2 (gene amplification by FISH or 3+ overexpression by immunohistochemistry) are not eligible unless they have received prior therapy with Herceptin.
* Patients must not have had a major surgical procedure within 4 weeks prior to study entry. (Placement of vascular access device, and breast biopsy, will not be considered major surgery.)
* Patients must not have had a minor surgical procedure, placement of an access device, or fine needle aspiration within 7 days of starting protocol therapy.
* Patients must not have had radiation within 2 weeks prior to study entry.
* Previously radiated area(s) must not be the only site of disease for study entry.
* Patients must not have a history of bleeding diathesis or have used anticoagulant therapy within 10 days of study entry. (Low dose anticoagulant therapy to maintain patency of a vascular access device is allowed.)
* Patients with a history of deep vein thrombosis or pulmonary embolism are not eligible.
* Aspirin usage (\> 325 mg/day) or other nonsteroidal anti-inflammatory medications known to inhibit platelet function daily are not allowed within 10 days prior to study entry.
* Patients currently using any of the following drugs known to inhibit platelet function are not eligible: dipyridamole (Persantine), ticlopidine (Ticlid), clopidogrel (Plavix) and cilostazol (Pletal).
* Patients must not have a history of TIA or CVA within 6 months prior to study entry.
* Patients must not have a history or radiologic evidence of CNS metastases including previously treated, resected or asymptomatic brain lesions or leptomeningeal involvement (head CT or MRI must be obtained within 6 weeks prior to study entry).
* Patients must not have a non-healing wound or fracture.
* Patients must not have a hypersensitivity to paclitaxel or drugs using the vehicle Cremophor, Chinese hamster ovary cell products or other recombinant human antibodies.
* Females must not be pregnant or breastfeeding. Females of childbearing potential must use an accepted and effective method of contraception (hormonal or barrier method of birth control; abstinence) while on treatment and for a 3 month period thereafter.
* Females of childbearing potential must have a negative pregnancy test within 7 days prior to being registered for protocol therapy. Subjects are considered not of child bearing potential if they are surgically sterile (they have undergone a hysterectomy, bilateral tubal ligation, or bilateral oophorectomy) or they are postmenopausal.
* History of abdominal fistula, gastrointestinal perforation, or intra-abdominal abscess within 6 months prior to study entry
* Urine protein: creatinine (UPC) ratio \> 1.0 at baseline or urine protein dipstick \> 2+.