The risk of developing breast cancer increases as women age and reach menopause. Many women who have, or are at risk, for breast cancer take tamoxifen.
The drug prevents approximately half of breast cancers in women who are likely to develop the disease. However, when women take tamoxifen, they cannot take hormone replacement therapies to relieve menopausal symptoms.
Their options are limited to taking antidepressants that can have complications, enduring uncomfortable menopausal symptoms, or trying the black cohosh.
"Hopefully, this study will provide evidence that black cohosh is safe to use for breast cancer patients. Currently, there is little reliable information guiding women in how they can use foods and botanical supplements to enhance their treatment or improve their quality of life," said Rachel Ruhlen, a postdoctoral researcher in the MU School of Medicine.
In order to study how black cohosh and tamoxifen interact, Ruhlen will use a group of rats prone to breast cancer, known as ACI rats.
Previous studies have found that human breast cancer is associated with life-time exposure of estrogen.
ACI rats, like humans, develop mammary tumours after exposure to estrogen. In a previous study, Ruhlen found that when ACI rats were treated with the human breast cancer drug tamoxifen, mammary tumour mass was reduced by 89 percent.
"Many animal models of breast cancer differ in important ways from humans with breast cancer," Ruhlen said.
"These models are useful in studying how human tumours grow and spread to other parts of the body, but fall short because of the difference in how human tumours begin.
"However, mammary tumours in ACI rats share several key features with the majority of human breast cancers, particularly in how tumours start. Because the ACI rats develop tumours and can be treated in a way similar to humans, it is a relevant model for human breast cancer," Ruhlen added.