Cody Ramin, Ph.D., Sc.M.

Postdoctoral Fellow

National Cancer Institute

Breast density is one of the strongest known breast cancer risk factors. Recent research suggests that there may be racial differences in breast density; some studies have found that Black women are more likely than White women to have higher breast density. However, factors that influence breast density and the underlying biological mechanisms by which density influences breast cancer risk are not well understood, and how these associations may differ by race remains unclear.

Growing evidence suggests that endogenous hormones (hormones produced by the body), which have been implicated in the development of breast cancer, may also affect breast density. Prior studies have found that increased endogenous estrogen levels are linked to increased breast density, but data on other endogenous hormones, including progesterone and androgens, are limited. The use of exogenous hormones (hormone therapy), however, further supports a hormonal basis for breast density. For example, tamoxifen, a selective estrogen receptor modulator with antiestrogenic effects in the breast, has been shown to reduce breast density, particularly among premenopausal women and those with high breast density. Declines in breast density after tamoxifen therapy are associated with improved breast cancer outcomes and may be a marker of treatment response. However, no studies to date have examined whether changes in endogenous hormones after tamoxifen therapy are associated with subsequent declines in breast density and, if so, whether this association varies by race.

Dr. Ramin proposes to examine the association between endogenous hormones and breast density before and after tamoxifen treatment among a racially diverse study population. Understanding how endogenous hormones influence breast density after tamoxifen therapy and whether there are differences by race may provide information about both breast cancer causes and racial disparities in breast cancer survival.