Dogs fed a diet supplemented with selenium show a lower level of DNA damage in their prostates compared with dogs fed a normal (unsupplemented) diet. The finding, which appears in the February 5 issue of the Journal of the National Cancer Institute, suggests that dietary selenium supplementation decreases cellular changes that may lead to prostate cancer.
David J. Waters, of Purdue University in West Lafayette, Ind., and his colleagues randomly assigned 49 elderly male dogs to a normal diet or one of four diets supplemented with different amounts of selenium. After 7 months, the prostates of dogs fed diets supplemented with selenium had less DNA damage than the prostates of dogs fed the normal diet. In addition, compared with dogs fed the unsupplemented diet, dogs fed the supplemented diet had a twofold increase in the number of prostate cells that had undergone apoptosis, a mechanism that can remove damaged cells.
The authors conclude that "selenium may benefit the aging prostate by decreasing the accumulation of DNA damage in epithelial cells even before these cells show cytotoxic changes suggestive of malignancy."
Retinoid May Have Potential in Chemoprevention of Lung Cancer
Treatment of former smokers with the retinoid 9-cis-retinoic acid (RA) may have the potential to prevent lung cancer, suggests a new study in the February 5 issue of the Journal of the National Cancer Institute. Jonathan M. Kurie, M.D., and Waun Ki Hong, M.D., of the University of Texas M. D. Anderson Cancer Center in Houston, and their colleagues, examined the effect of two retinoids, 9-cis-RA and 13-cis-RA plus a-tocopherol (AT), on the expression of RAR-ß in 226 former smokers. Loss of RAR-ß expression in the bronchial epithelium is considered a biomarker of premalignancy. The authors found that 9-cis-RA, but not 13-cis-RA+AT, restored RAR-ß expression and reduced squamous metaplasia.
Allele Associated with Decreased Response to Chemopreventive Agents
Former smokers who carry a specific allele of the cyclin D1 cell cycle regulatory protein may have a decreased response to chemopreventive agents, according to a study appearing in the February 5 issue of the Journal of the National Cancer Institute. Julie G. Izzo, M.D., of the University of Texas M. D. Anderson Cancer Center in Houston, and her colleagues compared cyclin D1 genotype of 31 individuals with their response to biochemopreventive treatment. The authors found that the A allele of cyclin D1 was associated with a decreased likelihood of response to biochemopreventive therapy and an increased rate of progression to upper aerodigestive tract cancer.
Note: The Journal of the National Cancer Institute is published by Oxford University Press and is not affiliated with the National Cancer Institute. Attribution to the Journal of the National Cancer Institute is requested in all news coverage.
Journal
JNCI Journal of the National Cancer Institute