Inclusion Criteria:

- For acquisition of existing breast cancer tissue specimens from the MSKCC Tissue
Procurement Service, the only criteria are a pathologically-confirmed diagnosis of
invasive breast cancer and the availability of corresponding nonmalignant tissue from
each case.

- For the prospective acquisition of blood or saliva from control subjects without
breast cancer, eligibility criteria include:

- Any patient with a previous diagnosis of invasive breast cancer who undergoes a
palliative procedure related to the presence of a pleural effusion is eligible for
the pleural fluid collection aspect of this protocol.

- Any female patient, or any female over the age of 18 accompanying a patient under the
care of a physician in the Department of Urology, Department of Surgery, or
Department of Medicine.

- Subjects will have no history of preinvasive (carcinoma in situ) or invasive breast
cancer.

- Subjects will be eligible without regard to racial, or ethnic status. Attending
physicians authorized to obtain informed consent may exercise discretion in excluding
individuals for appropriate medical or other (e.g., mentally impaired) reasons.

- For the prospective acquisition of blood, saliva, pleural fluid or cerebrospinal
fluid from patients who have or are suspected of having breast cancer or carcinoma
in-situ, eligibility criteria include:

- Any patient at MSKCC with a previously confirmed or suspected diagnosis of malignant
or premalignant (e.g., carcinoma in situ) breast disease is eligible for inclusion in
the blood acquisition aspect of this protocol.

- Any patient with a previous diagnosis of invasive breast cancer who undergoes a
palliative procedure related to the presence of a pleural effusion is eligible for
the pleural fluid collection aspect of this protocol.

- Any patient with a previous diagnosis of invasive breast cancer with leptomeningeal
metastasis who undergoes a routine procedure associated with the collection of
cerebrospinal fluid is eligible for the cerebrospinal fluid collection aspect of this
protocol.

- All subjects must be under the care of one or more members of the MSKCC Breast
Disease Management Team at the time of enrollment.

- Subjects may have received prior hormonal therapy, cytotoxic chemotherapy, radiation
therapy, or surgical therapy at MSKCC or another institution.

- All subjects must be 18 years or older

- Subjects will be eligible without regard to sex, racial, or ethnic status. It is
anticipated that approximately 99% of the patients will be female. Attending
physicians authorized to obtain informed consent may exercise discretion in excluding
individuals for appropriate medical or other (e.g., mentally impaired) reasons.

- If, after pathologic diagnosis, preinvasive or invasive breast disease is not found,
patients previously consented for the blood collection aspect of this protocol will
not be included.

Exclusion Criteria:

- For the prospective acquisition of blood or saliva from control subjects without
breast cancer, ineligibility criteria include:

- A first degree relative (mother, daughter, sister, father, brother or son) who
has been diagnosed with breast cancer.

- A personal history of breast cancer, lobular carcinoma in situ or atypia.