By Karla Gale
NEW YORK (Reuters
Health) - Comprehensive diet and lifestyle modifications alter gene expression in prostate tissue of men with low-risk prostate cancer, investigators report in a prospective pilot study. The results showed that expression of genes involved in tumorigenesis were down-regulated.
"Simple changes in diet and lifestyle have a powerful impact on gene expression," Dr. Dean Ornish, from the Preventive Medicine Research Institute in Sausalito, California, told reporters in a press briefing.
"Two years ago, (we) published the first randomized controlled trial showing that intensive lifestyle changes may slow, stop or even reverse the progression of early stage prostate cancer, and perhaps breast cancer as well," he continued. "At that time, we did not understand the mechanisms by which those changes occurred."
The Gene Expression Modulation by Intervention with Nutrition and Lifestyle (GEMINAL) study was designed to explore the molecular mechanisms involved, he added.
The trial included 30 men with early stage, nonaggressive prostate cancer, with stable prostate specific antigen (PSA) levels and Gleason scores of 6 or less. The patients had elected to forego conventional treatment while undergoing surveillance for tumor progression, according to the report, published in the June 17th Proceedings of the National Academy of Sciences.
The 3-month lifestyle intervention involved "low-fat, whole-foods, plant-based nutrition; stress management techniques; moderate exercise; and participation in a psychosocial support group."
Needle biopsies of prostate tissue were taken at baseline and after 3 months, from which RNA was extracted for gene expression array analysis of 40,000 genes.
Results showed that 48 genes were up-regulated and 453 were down-regulated. "Pathway analysis identified significant modulation of biological processes that have critical roles in tumorigenesis, including protein metabolism and modification, intracellular protein traffic, and protein phosphorylation," the authors report.
Significant improvements in
cardiovascular disease risk factors were also observed, including reductions in BMI, blood pressure, waist circumference, and lipid levels.
"It is striking that there were so many changes to such a degree," co-author Dr. Christopher M. Haqq, from the University of California San Francisco, said during the press conference.
"If this had been a drug that we tested, with that degree of change, it would be a block-buster home-run for a drug company," he added.
"These findings may be an antidote to 'genetic nihilism,'" Dr. Ornish said. "Our genes represent our predisposition but not our fate. Knowing that these mechanisms are much more dynamic than we once realized may help capture people's imagination and motivate them to make beneficial lifestyle changes."