Washington: Scientists have revealed that lifelong exposure to genistein, a bioactive component in soy foods, protects against colon cancer by repressing a signal that leads to accelerated growth of cells, polyps, and eventually malignant tumors.
"In our study, we report a change in the expression of three genes that control an important signaling pathway," Hong Chen, a University of Illinois professor of food science and human nutrition, said.
The cells in the lining of the human gut turn over and are completely replaced weekly, she said.
"However, in 90 percent of colon cancer patients, an important growth-promoting signal is always on, leading to uncontrolled growth and malignancies. Our study suggests that the aberrant Wnt signaling during the development of colon cancer can be regulated by soy-rich diets," she said.
"The good news is that a diet rich in soy genistein represses those signals through epigenetic modifications at the regulatory regions of those genes," Yukun Zhang, a doctoral student in Chen`s laboratory, said.
Chronic exposure to genistein, a soy isoflavone, reduced the number of pre-cancerous lesions in the colons of laboratory rats exposed to a carcinogen by 40 percent and reduced Wnt signaling to normal levels, she said.