Soy Food Consumption Reduces Recurrence Of Breast Cancer

Could the consumption of soyfood reduce the recurrence of breast cancer in some women? New findings presented at the American Association for Cancer Research (AACR) Annual Meeting 2015 suggest that eating soy foods or soy-based supplements could help, according to researchers at Georgetown University.

"I am concerned that some patients may start taking soy supplements when they shouldn't and that others will stop eating soy foods when they could really benefit from them," Leena Hilakivi-Clarke, lead investigator of the study, said in a news release.

Soy can stimulate the growth of breast cancer cells and disrupt anti-estrogen treatment stems from mice studies that use mice that do not have immune cells known as cytotoxic T cells, known to attack breast cancer, which led scientists to advise their breast cancer patients not to eat soy foods.

However, in a previous study conducted by Hilakivi Clarke and Xiyuan Zhang, the lead author of the current study, confirmed that rats that consumed genistein, an isoflavone found in soybeans, fava beans and soy milk, among other soy foods, throughout their lifetimes responded better to anti-estrogen treatment than did control rats.

For the study, researchers examined previous findings that explained changes in tumor immune responses. The T cells can attack tumor cells while the other immune cells disable the ability of the T cells to recognize the tumors that are present and allowing breast cancer to grow unchecked in the immune system.

Researchers found that the T cell immune response was already activated in rats fed genistein before puberty with tamoxifen. The tumor's attempt to hide from an immune system attack had also been thwarted during the treatment.

"Our results suggest that genistein's ability to activate anti-tumor immune responses and reduce expression of immunosuppressive mechanisms may explain why lifetime genistein intake reduces risk of breast cancer recurrence," Hilakivi-Clarke concluded.