Why does hormone replacement therapy lead to increased breast cancer risk?

Start Year: 2012
Finish Year: 2014
Chief Investigator: Dr Nicole Moore
Grant Type: Novel Concept Awards
Institution: University of Adelaide

Millions of women take combined oestrogen plus progestin hormone replacement therapy (cHRT) for relief of menopausal symptoms, despite cHRT being associated with an increased breast cancer risk.

A better understanding of cHRT effects in the breast and how this influences cancer development will enable patients and doctors to make better choices about cHRT. The progestin component of cHRT is implicated in promoting breast cancer. The most commonly used progestin in Australia is medroxyprogesterone acetate (MPA). MPA functions by binding to protein receptors which then influence cell growth and death, but it is not clear which receptors cause the detrimental effects of MPA in breast cells.

Dr Moore is investigating MPA action through progesterone, androgen and glucocorticoid receptors in breast tissue. Dr Moore aims to gain a better understand how MPA works at the cellular level and how it may promote breast cancer. The outcomes of this study will potentially influence policies on MPA use and reduce breast cancer risk for current and potential cHRT users.