The purpose of this study is to find out if there is a link between cigarette smoking, inflammation and the spread of breast cancer to the lung. We think that women who are current or former smokers may be at increased risk for breast cancer spreading to the lung compared to women who have never smoked. Smoking causes inflammation in the lung in some women. Researchers at Memorial Sloan-Kettering (MSKCC) think that smoking-related lung inflammation may increase the chance of breast cancer spreading to the lung. In order to find out whether inflammation plays a role in breast cancer spreading to the lung, we will measure a urinary marker of lung inflammation. This will allow us to determine if this marker is more commonly elevated in women with breast cancer that has spread to the lung compared to those without breast cancer in the lung. We will also collect DNA from blood to have the opportunity to determine if there are differences in DNA in women with or without breast cancer that has spread to the other sites including the lung. We will also collect blood to determine if we can identify risk factors for the spread of breast cancer to the lungs.

Inclusion Criteria:

• Registered patient at MSKCC
• Histologically proven breast cancer. It is not necessary that pathology be reviewed at MSKCC
• Age ≥18 years Group 1 (A and B)
• Diagnosed with metastatic breast cancer on biopsy or imaging study.
• Patients will be considered to have lung metastases, and will be assigned to group 1A if any of the following criteria are met, otherwise patients will be assigned to group 1B "No known Lung Metastases," Biopsy-proven lung metastasis.
• Pleural effusion with cytologic evidence of malignancy.
• Pleural effusion, exudative in character, without alternative explanation and attributed, in the opinion of the clinician to metastatic disease.
• Symptoms attributable to lung metastases and a radiological pattern interpreted by a radiologist as suspicious for metastatic disease.
• Any pulmonary nodule on chest radiograph, CT scan, PET-CT or MRI, which is interpreted by the clinician and radiologist to be metastatic in etiology, whether or not a biopsy was performed, and regardless of symptoms.
• A radiographic pattern interpreted by a radiologist as consistent with lymphangitic carcinomatosis.

Group 2 (Controls)

• History of early breast cancer and currently no evidence of disease

Exclusion Criteria:

• Inability to provide written informed consent.
• Inability to complete smoking and NSAID questionnaire.
• Steroid use within the previous 4 weeks.
• Radiotherapy to the breast, chest wall or axilla within the previous 3 months.
• Men with breast cancer.

All patients who meet the above inclusion and exclusion criteria will be approached by a member of the study team and be asked to participate.