Physical activity reduces prostate carcinogenesis in a transgenic model.

BACKGROUND: Several epidemiological studies have reported an inverse association between physical activity and the risk of prostate cancer. To date, there are few animal studies looking at physical activity and cancer incidence, although the results are consistent with the epidemiological evidence. In general, as exercise intensity increased in the rats/mice, the likelihood that physical activity inhibited carcinogenesis increased.
METHODS: The present study used voluntary wheel running with C3(1)Tag mice that are predisposed to prostate cancer due to the directed expression of SV40 oncogenes. After 10 weeks, the prostates were collected from run and non-run mice and histopathology performed for the presence or absence of low grade or high grade PINS.
RESULTS: We found that for those mice that ran >5Km/group, 83% of the dorsolateral prostates were classified as within normal levels vs. 43% for the <5 km/day group (p = 0.16). In addition, there was a relationship between average distance run and pathologic progression to high-grade PIN and local invasion, considered to be an early event in the formation of prostate adenocarcinoma. Forty three percent of dorsalateral prostates from mice that ran less than 5 km/day were classified with advanced pathology as compared to none (0) in mice that ran more than 5.0 km/day (p = 0.05).
CONCLUSIONS: The results presented herein indicate that prostatic cancer progression is likely delayed or diminished by wheel running activity in a dose dependent manner in transgenic mice. These findings provide further evidence that exercise acts to decrease the progression of prostate cancer and they establish a transgenic animal model for future studies to define mechanism(s). Prostate 69: 1372-1377, 2009. (c) 2009 Wiley-Liss, Inc.