Men with early-stage prostate cancer who exercise vigorously at least three hours a week have more than 180 genes that are expressed differently in the prostate gland than those who did not exercise as intensively. These genes include known tumor suppressor genes and DNA repair pathways, suggesting that a better understanding of the molecular effects of exercise may guide development of strategies to prevent or delay cancer progression.

The results of the study confirming the effects of vigourous excercisewere presented at the fourth annual Genitourinary Cancers Symposium, being held February 2-4, 2012, at the San Francisco Marriott Marquis in San Francisco, Ca, USA.

Patients fare better
?We previously reported that prostate cancer patients who exercise tend to fare better after a diagnosis of prostate cancer, and now we are trying to understand why,? said senior author June Chan, ScD, associate professor, epidemiology and biostatistics and urology, and the Steven and Christine Burd-Safeway Distinguished Professor at the University of California, San Francisco. ?These preliminary findings give us several good leads on which molecular mechanisms may be influenced by physical activity and involved in prostate cancer progression and should be studied more closely in a larger scale study. We hope such data can be used to identify new gene signatures that predict progression and prognosis, which would have a broad impact on many aspects of prostate cancer care.?

Benefits of physical activity
In two separate studies last year, Chan and her colleagues reported links between exercise, especially vigorous activity or a brisk walking pace, and a lowered risk of disease progression and death among men with prostate cancer. Physical activity has been reported to offer benefits for other cancers as well, including breast and colorectal cancer. To explore potential molecular mechanisms behind this protective effect, the researchers examined possible correlations between exercise and prostate gene expression patterns in men with low-risk prostate cancer who were undergoing ?active surveillance,? rather than active treatment. They used data on gene expression from normal prostate tissue samples in 70 men obtained from an earlier study that had examined the effects of nutritional supplements on the normal prostate. As part of that study, the men completed a questionnaire about their exercise habits, including the amount and intensity of exercise.

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BRCA1 and BRCA2
The investigators observed 184 significant genes that were expressed differently between those men who participated in more vigorous exercise ? such as jogging, tennis or lap swimming ? for at least three hours a week and those who reported less intense physical activity, such as walking at any pace. Genes that were more highly expressed in the vigorous activity group included both well-known tumor suppressor genes associated with breast cancer, BRCA1 and BRCA2. Greater expression of molecular pathways involved in cell cycle and DNA repair were also observed in the group participating in more versus less physical activity.

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DNA repair
?This was a small study with provocative findings that should be interpreted cautiously and warrant confirmation in a larger study. These preliminary data suggest that DNA repair in the prostate gland is one mechanism through which vigorous physical activity may protect against prostate cancer progression, and there are potentially more,? Chan said. ?If our findings are substantiated, and we can determine which molecular differences really matter for disease recurrence, then these signals could be used to improve monitoring of prostate cancer and its response to any intervention.?

Patient education
Chan?s team hopes to confirm its findings in a larger group of men on active surveillance, as well as examine the effects of physical activity among men who have already experienced cancer recurrence. The investigators are also collaborating to develop new patient education strategies that reinforce the value of physical activity and other healthy lifestyle practices that may improve prostate cancer outcomes.

For more information:
Mendoza Magbanua MJ, Richman EL, Sosa EV, Jones L, Simko J, Shinohara K, Haqq CM, Carroll P, Chan JM. Physical activity and prostate gene expression in men with low-risk prostate cancer. Abstract #189

General Poster Session C
Senior Author: June Chan, MD
When:Friday, February 3, 2012; 12:15 PM – 01:45 PM PT

The Genitourinary Cancers Symposium is co-sponsored by the American Society of Clinical Oncology (ASCO), the American Society for Radiation Oncology (ASTRO) and the Society of Urologic Oncology (SUO).

Illustration published with permission from American Society of Clinical Oncology (ASCO)

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