Vitamin A May Prevent Lung Cancer In Former Smokers A synthetic vitamin A analog appears to exert chemopreventive activity in former heavy smokers by reducing the activity of telomerase, which is important in carcinogenesis, in the lungs. "Given that 50% of new lung cancer [cases manifest in] former smokers, this may be a population that can benefit from blocking the carcinogenic process," Dr. Li Mao announced at a press briefing at the 92nd Annual Meeting of the American Association for Cancer Research. Dr. Mao and associates, of the M. D. Anderson Cancer Center in Houston, analyzed TERT, the catalytic subunit of telomerase, in 57 heavy smokers enrolled in a randomized double-blinded chemoprevention trial. Biopsies were obtained at six bronchial sites in each subject before and after 6 months of treatment with the analog, N-(4-hydroxyphenyl) retinamide (4-HPR), or placebo. At baseline, mean expression rates of TERT were 62.4% in the 4-HPR group and 65.3% in the placebo group. TERT expression was observed both in morphologically abnormal tissues and in normal-appearing bronchial epithelium. "This is the first study to demonstrate that TERT is widely expressed in bronchi of chronic smokers," Dr. Mao said. By the end of the study, TERT expression was significantly reduced to 45.6% in the 4-HPR group, while it had increased slightly to 68.1% in the placebo group. "This decrease suggests that [4-HPR] may reduce lung cancer," Dr. Mao stated. "Because the development of lung cancer spans decades, it is very difficult to use cancer incidence as an end point in initial chemopreventive trials," he said. He added that this is what makes the discovery of TERT as a sensitive biomarker for risk assessment and for evaluating the effectiveness of chemopreventive agents so exciting. Thanks to Reuters Health Comments on the 1994 Finnish CARET Study 6/03 comments by Abram Hoffer, MD Remember we are NOT Doctors and have NO medical training. This site is like an Encylopedia - there are many pages, many links on many topics. Support our work with any size DONATION - see left side of any page - for how to donate. You can help raise awareness of CAM.