Modulation of Breast Cancer Risk Biomarkers by High Dose Vitamin D

Protocol Objectives:

To determine if high dose vitamin D3 given to premenopausal women who initially have
insufficient levels of 25-hydroxy vitamin D (<30 ng/ml) will raise 25(OH)D levels above the
50 ng/ml level considered to be required for breast health. If so, will certain risk
biomarkers for development of breast cancer be reliably and favorably modulated? The primary
endpoint will be a decrease in mammographic breast density (percent area considered at
increased density). Change in proliferation (a decrease as assessed by Ki-67) will also be
examined. Modulate of expression of genes important in breast cancer risk or reflective of
vitamin D's mechanism of action will be studied using quantitative real time polymerase
chain reaction (qRT-PCR).

Study Design:

The study is a single-arm open label clinical trial. Women who are high risk for development
of breast cancer on the basis of family or personal history will undergo random periareolar
fine needle aspiration (RPFNA) to acquire breast cells for assessment of gene expression by
qRT-PCR. Women with mammographic density >10% will be eligible for enrollment. All subjects
will receive high dose vitamin D3 (3 capsules of 10,000 IU of vitamin D3 every week for 6-8
months). At that time, a repeat RPFNA and mammogram will be performed. Measurement of serum
levels of 25(OH)D will be performed at baseline, 3 months, and 6 months.

Inclusion Criteria:

- Subjects must be premenopausal women age 55 or younger, and actively menstruating
with 4 or more periods per year.

- Subjects may be using barrier contraceptive, an intrauterine device, a Nuvaring, or
similar non-oral contraceptive; or oral contraceptives.

- Subjects must be at increased risk for breast cancer on the basis of at least one of
the following criteria:

- five-year Gail risk of 3X the average risk of the age group;

- a first degree relative with breast cancer under the age of 60 or multiple
second degree relatives with breast cancer;

- prior biopsy exhibiting atypical hyperplasia (AH), LCIS, DCIS, RPFNA evidence of
hyperplasia with atypia within the last three years;

- Chest or neck radiation before age 30;

- Breast density equals or exceeds 50 percent.

- If previously on a chemoprevention agent or prevention trial, subjects must have
completed study participation at least 6 months prior to baseline biomarker
assessment.

- If subject has a history of AH, LCIS, or ER-positive DCIS by diagnostic biopsy, must
have been counseled about appropriate standard prevention therapies such as tamoxifen
and is either not eligible or is not interested in standard prevention therapies.
Women with DCIS must have had appropriate local therapy (lumpectomy plus radiation or
mastectomy).

- Subject must have had a mammogram performed at the University of Kansas Breast
Imaging Center with estimated visual breast density of greater than 10 percent.

- Subject must have had within six months prior to entering the study, an RPFNA during
the follicular portion (day 1-10) of the menstrual cycle with material for
cytomorphology, Ki-67 and qRT-PCR; in addition to serum obtained and banked.

- Subjects must have 25(OH)D level < 30 ng/ml as measured within 8 weeks of starting
intervention. Subjects may have been identified as having low vitamin D levels
through participation in HSC 11313, Osteopenia/Osteoporosis in Pre-menopausal Women
at High Risk for Development of Breast Cancer, but low level must be confirmed within
8 weeks prior to starting study agent Subject must be willing to continue the same
hormonal milieu present at baseline throughout trial.

- Subjects must be willing to undergo measurement of height, weight, and BMI at
initiation of intervention.

- Subjects must have participated in HSC 11313, and have had a DEXA scan for bone
density and body fat analysis on the GE Lunar Prodigy Advance research unit in the
Breast Cancer Survivorship Center.

- Subjects must be willing to sign an informed consent for the entire study and
separate consent for repeat RPFNA.

Exclusion Criteria:

- Women that have had a metastatic malignancy of any kind.

- Women that have had prior invasive breast cancer If subject has had a DCIS, at least
two months must have elapsed from surgery and/or radiation therapy to the involved
breast. Only the contra-lateral (uninvolved breast) will be studied by FNA. The
subject may not have had any radiation therapy to the contra-lateral breast to be
studied.

- Women who are pregnant or nursing.

- Women who have taken a SERM, aromatase inhibitor or participated in a chemoprevention
or other investigational drug study within six months prior to baseline FNA.

- Women who have used fertility drugs within six months prior to baseline aspiration.

- Women with a history of sarcoidosis, hypercalcemia, hyperparathyroidism, or renal
stones.

- Women who are receiving treatment for rheumatoid arthritis or other connective tissue
diseases.

- Women who have an elevated blood calcium level at baseline; defined as any elevation
above the institutional normal range.