A new study has reported that dietary blueberry reduces triple negative tumor growth and metastasis in a mouse model of breast cancer. Triple negative is a subtype of breast cancer that is estrogen receptor negative (ER-), progesterone receptor negative (PR-), and human epidermal growth factor receptor 2 negative (HER2-). The authors previously demonstrated that blueberry extract exhibited antitumor activity against MDA-MB-231 triple negative breast cancer cells and reduced the cells' metastatic potential. In the present study, female mice were implanted with MDA-MB-231 triple negative breast cancer cells. The mice were fed whole blueberry powder, comprising either 5% or 10% of the diet, or a blueberry-free control diet.

Compared to control mice, tumor volume was found to be 75% lower in mice fed the 5% blueberry diet and 60% lower in mice fed the 10% blueberry diet. Tumor cell proliferation was lower in both groups of blueberry-fed mice and cell death was greater in the 10% blueberry-fed mice. The authors also performed gene analysis of tumor tissues from the 5% blueberry-fed mice, which showed significantly altered expression of genes important to inflammation, cancer development, and metastasis. The authors also conducted a second study to evaluate the ability of the 5% blueberry diet to inhibit MDA-MB-231-luc-D3H2LN metastasis in vivo. This triple negative cell line has a heightened tendency to metastasize. In this study, mice fed 5% blueberry developed 70% fewer liver metastases and 25% fewer lymph node metastases than control mice.

Please see our article on what triple negative breast cancer patients should eat for more information.