Vitamin D3 Treatment Influences PGE2 and TGFβ in Normal and Increased Breast Cancer Risk Women.

Background/aim: We reported that vitamin D3 increased transforming growth factor (TGF)β2 and decreased prostaglandin (PG)E2 in the breast of normal-risk women, suggesting a protective effect. We determined if the findings held for higher risk women. Patients and

Methods: Seventy-eight women received daily for one month/menstrual cycle: placebo, 400 international units (IU) vitamin D3, 2,000 IU vitamin D3 or 2,000 IU vitamin D3/400 mg celecoxib. Nipple aspirate fluid (NAF) and/or serum were analyzed for PGE2, TGFβ1,-2, vitaminD binding protein (DBP) 25(OH)D; and plasma for celecoxib.

Results: 25(OH)D increased (p<0.001) in women receiving 2,000 IU vitamin D3. Two thousand IU vitamin D3 lowered NAF PGE2 in normal-risk women (p=0.029), whereas 2,000 IU vitamin D3/celecoxib lowered NAF PGE2 in high-risk women (p=0.063). Serum TGFβ1 was influenced by treatment (p=0.011). NAF TGFβ2 increase correlated with increase in 25(OH)D. DBP serum levels were higher than matched NAF, regardless of race, and did not appreciably change with treatment.

Conclusion: Vitamin D3 influenced TGFβ1 and -β2 expression. PGE2 response to vitamin D3 treatment was influenced by a participant's breast cancer risk. The implications of these observations regarding breast cancer risk should be further evaluated.