Breast Stem Cells in Women at Average Risk and Increased Risk for Breast Cancer

* INCLUSION CRITERIA:

Women age 18 and older.

No abnormal findings in the breast by physical examination.

Average Risk: must meet all criteria below.

* Gail model index of less than 1.7% over next 5 years.
* Claus model lifetime risk less than 10%.
* BRCAPro and Couch model less than 10% of being a BRCA mutation carrier OR tested negative for documented deleterious BRCA1/2 mutation in family.

Increased risk for invasive breast cancer by one of the following:

* Gail Model risk of greater than 1.7% over 5 years from study entry.
* Claus model lifetime risk to age 79 greater than or equal to 10%.
* History of high risk pathologic lesion: lobular carcinoma in situ, atypical hyperplasia, DCIS (ductal carcinoma in situ).
* Deleterious mutations in BRCA1/2, PTEN or P53.
* Greater than or equal to 10% chance of carrying BRCA1/2 gene mutation as assessed by BRCAPro and Couch model (22, 23). If a woman has a 20% risk of carrying a BRCA1/2 mutation by either model, she will meet eligibility criteria.
* History of unilateral breast cancer either invasive or in situ, and a normal contralateral breast by physical examination.

Willing to stop NSAIDS for 3 days prior to biopsy and aspirin 7 days prior to biopsy.

If history of cancer (other than squamous or basal cell skin cancers), subject must have no evidence of disease at time of enrollment AND no history of cancer directed treatment in the 3 months preceding enrollment.

Identification of dense area of breast tissue suitable for biopsy identified on mammogram by the radiologist.

EXCLUSION CRITERIA:

Current use of hormonal therapies (e.g. tamoxifen, aromatase inhibitors, hormone replacement therapy, oral contraceptive pills, topical or vaginal hormone medications are allowed.)

Chemotherapy and radiation within 3 months prior to breast biopsy procedure.

Breastfeeding within 3 months.

Pregnancy (determined by urine dipstick).

A suspicious unbiopsied lesion by physical examination or mammography of the breast(s) which is being studied.

Bleeding disorder.

Warfarin, low molecular weight heparin, or heparin use.

History of bilateral breast radiation.