Gene Expression Profile of Breast Cancer Samples After Vitamin D Supplementation

The purpose of this study is to evaluate whether calcitriol supplementation may reduce tumor cell proliferation and influence gene expression profile of breast cancer samples from post-menopausal patients.

Women affected by breast cancer present lower 1,25(OH)2D3 or 25(OH)D3 serum levels than unaffected ones. Calcitriol supplementation may be indicated to post-menopausal women to reduce bone loss. Vitamin D has antiproliferative effects in breast cancer cell lines and breast cancer xenografts.

Post-menopausal breast cancer patients will be prescribed calcitriol supplementation, in doses indicated to prevent osteoporosis, while they are submitted to biopsy, staging exams and have their breast surgery scheduled (approximately one month). Tumor dimension and proliferation rate (as determined by Ki67 expression), 25(OH)D3 and/or 1,25(OH)2D3 serum concentration, will be evaluated before and after calcitriol supplementation. Tumor gene expression will be evaluated in samples collected before and after supplementation to analyze the differential profile.

• Breast Neoplasms
• Postmenopausal Disorder

• Drug: calcitriol
  Post menopausal patients will receive Calcitriol 0.50 mcg PO per day for 1 month.
  Other Name: Rocaltrol
• Drug: Calcitriol
  calcitriol 0.25 mcg PO bid
  Other Name: Rocaltrol

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Inclusion Criteria:

• Postmenopausal women
• Invasive breast carcinoma
• Clinical conditions for breast surgery
• No previous neoadjuvant treatment for breast cancer
• Agreement to take part in the study and sign the informed consent

Exclusion Criteria:

• History of hypercalcemia or nephrolithiasis
• Current use of corticosteroids, vitamin D supplementation, HRT
• Previous chemotherapy, hormonotherapy or radiotherapy
• Parathyroid disease
• Absence of clinical condition to receive supplementation