Soy protein prevents skin tumors in mice, researchers report

By Sarah Yang, Public Affairs

Nutritional Sciences Professor Ben de Lumen heads the lab where soy protein’s anti-cancer properties were first discovered. Jane Scherr photo

07 November 2001 | New research may add yet another boost to the healthy reputation of the humble soybean. A study published Oct. 15 in the journal Cancer Research shows that mice with the soy protein lunasin applied to their skin had significantly lower rates of skin cancer than mice without the lunasin treatment.

More than two years ago, the same Berkeley researchers discovered that injecting the lunasin gene into cancer cells in a culture stopped cell division. In their latest work, they tested whether the lunasin protein could prevent normal cells from becoming cancerous in both cell cultures and in mice.

In the study, varying doses of lunasin were applied to groups of mice over a period of 19 weeks. They were compared with a control group that had received no lunasin treatments.

“In the high dose group, some mice did develop some tumors, but there were fewer tumors per mouse and there was a two-week delay in their appearance compared with the control group,” said Ben de Lumen, nutritional sciences professor in the College of Natural Resources and principal investigator of the study.

De Lumen is a member of the Health Sciences Initiative, a partnership among biomedical sciences and technology programs geared towards advancing research into today’s major health problems. He heads the lab where lunasin’s anti-cancer properties were first discovered, and where Alfredo Galvez, lead author of the study, worked as a post-doc researcher.

“The chemical changes that occur in normal cells before and during cancer formation signal lunasin,” said de Lumen. “We believe lunasin is like a watchdog; it’s out there sniffing. When it sees a normal cell transforming, it gets in there and attacks the cell.”

Studies on the health effects of soy products have been building over the years. Epidemiological studies in Japan and China, where soy-rich diets are common, show people in those regions have significantly lower rates of certain cancers and heart disease than people in Western countries, where typical diets contain little to no soy.