Ki-67 (or Ki67) is used as a measure of the proliferative activity of breast cancer cells. Ki-67 can often, but not always, be found on breast cancer pathology reports. High Ki-67 has been linked to unfavorable breast cancer outcomes in numerous breast cancer studies. Please see our article on Ki-67 and breast cancer for more information.
Below we focus on foods that have been shown to reduce or increase proliferation of breast cancer cells in the laboratory.

Foods that have been shown to lower proliferation

The following foods have also been shown to reduce breast cancer cell proliferation, but there is not enough other positive evidence concerning their chemopreventive effects to put them on our recommended list:
Women with type 2 diabetes tend to have tumors with higher Ki-67 than non-diabetics. However, the anti-diabetes drug metformin has been shown to reduce proliferation.

Foods and supplements that have been shown to increase proliferation

The following foods and supplements have been found to increase breast cancer cell proliferation in the laboratory:
The U.S. beef, veal and lamb industries use zeranol (Ralgro), a non-steroidal formulation with estrogenic activity, as a growth promoter. Zeranol has been found to stimulate human breast cancer cell growth and proliferation.
Exposure to bisphenol A (BPA) has been shown to increase proliferation of HER2+ and triple negative breast cancer cells.
Please see our article on how to optimize your breast cancer diet for information on what to eat during all stages of treatment and recovery. Below are links to recent studies on inflammation. For a more complete list of studies, please click on the tag Ki-67.