The purpose of this trial is to test the safety of a vaccine made from a patient's own breast cancer cells, and determine if this vaccine will delay or stop the growth of the cancer. The vaccine is made by genetically modifying a patient's own tumor cells to secrete granulocyte-macrophage colony-stimulating factor (GM-CSF) to activate the immune response.

After the patient has given their consent to participate in the trial, a series of tests will be performed to determine if the patient is eligible. These tests may take place up to 21 days before the surgery to remove a tumor sample or cancer-containing fluid, which will be used to create the vaccines. The tumor cells or fluid is then brought to a special, certified laboratory where the vaccine is made. Specially trained laboratory technicians then use a method known as adenoviral mediated gene transfer, which adds a new gene to the cancer cells. This gene causes the cells to make GM-CSF, a powerful hormone that stimulates the immune system. The cells are then given radiation so that they will not grow. Participants will start receiving vaccine on day 1, 8, 15, 29, and then every two weeks until the supply of vaccine has run out. The amount of the vaccine depends upon the total amount of cells that are obtained from the breast cancer tumor or fluid. Each time the patient is vaccinated, they will be given injections that will be placed underneath the skin. A different place will be used for each injection. If there are enough cells from the patient's tumor sample, the patient will be given an injection of non-transduced irradiated cells (the gene was not added) . These cells will help to measure how the patient's immune system is reacting to the tumor cells. This is called Delayed-Type Hypersensitivity (DTH). With vaccine #1 and #5, the patient will also receive a DTH injection. Two to three days after the vaccine and DTH injection, skin biopsies will be taken of both sites. At week 10 in the study treatment, or earlier if necessary, the patient will have a chest, abdomen, and pelvic CT scan to determine if the vaccine therapy has had an effect on their disease. A brain MRI will be performed if there were any abnormalities on the first brain MRI or if new symptoms have developed. Patients may participate in this study until one of the following happens: All vaccine created from the tumor has been given to the patient; the patient's disease worsens; the patient experiences an unacceptable and/or harmful side effect; the patient is unable to follow the study plan; or the patient's doctor feels it is no longer in the best interest of the patient to continue.

Inclusion Criteria:

• Histologically confirmed Stage IV breast cancer
• Prior banked malignant effusion or significant malignant effusion for tumor harvest or surgically-accessible tumor nodule of at least 2cm in greatest diameter by physical exam, magnetic resonance imaging (MRI) or computed tomography (CT) scan
• Must have received at least one prior regimen of chemotherapy for metastatic disease
• Patients with HER2 positive tumors must have received at least one prior trastuzumab-based therapy in the metastatic setting, and may not receive trastuzumab therapy and vaccine treatment concurrently
• Patients may receive concurrent bisphosphonate therapy and/or erythropoetin therapy at any point while on study
• ECOG performance status 0 or 1
• Estimated life expectancy of greater than or equal to 6 months
• 18 years of age or older
• Greater than 4 weeks from immunotherapy, or systemic glucocorticoid therapy
• Adequate recovery from drug-related toxicities from prior systemic therapies
• Adequate recovery from recent surgery and radiation therapy
• Greater than 6 months since bone marrow or peripheral blood stem cell transplant

Exclusion Criteria:

• Urgent need for cytotoxic chemotherapy, radiotherapy, or surgery in the next 60 days
• Uncontrolled active infection or illness
• Psychiatric illness/social situation that would limit study compliance
• Pregnant or nursing mothers
• Evidence of HIV infection
• Previous participation in an adenovirus-based trial
• Concurrent invasive malignancy