A gene believed to suppress the growth of tumors may be switched off in the early stages of breast cancer, according to results of a new study. But a two-pronged treatment that includes a form of vitamin A may help prevent or treat cancer by reactivating the tumor-suppressing gene, researchers report. A gene called RAR-beta-2, which is believed to stop tumors from growing, is switched off in several types of tumors, including breast cancer. Since substances called retinoids, which are similar in structure to vitamin A, are thought to interact with this gene, Dr. Martin Widschwendter from the University of Innsbruck, Austria, and colleagues studied the effects of a retinoid called ATRA on breast cancer cells. Suspecting that the RAR-beta-2 gene was deactivated by a process called methylation, the researchers treated several types of breast cancer cells with a substance that reverses this process, a demethylating agent. Then the cells were exposed to ATRA. In several of the 16 varieties of breast cancer cells tested, the RAR-beta-2 gene was reactivated after the two-pronged treatment, the researchers report in the May 17th issue of the Journal of the National Cancer Institute. In another line of cells in which the gene was already activated, or expressed, before the treatment, the expression increased. In other types of cells, the activation of the gene either did not increase or did not occur at all, according to the report. In another experiment involving breast tumors as well as a sample of normal breast tissue, the investigators found that the activation of the RAR-beta-2 gene was linked with cancer. While the researchers did not detect signs of methylation--the process that switches off the gene in normal breast tissue--they did detect them in six of the eight tumors studied. And later-stage tumors were more likely to have the gene switched off, according to the report. The study's authors point out that drugs that reverse the methylation process have been beneficial in animals with cancer. Based on the research, they conclude that reversing this process and giving retinoids may help prevent cancer. The vitamin A clones eventually may have a role in cancer treatment, according to Dr. Michael B. Sporn, of Dartmouth Medical School in Hanover, New Hampshire. But not yet, since the drug used in the study to switch the gene back on is too toxic to use in people, he notes in an editorial that accompanies the study. SOURCE: Journal of the National Cancer Institute 2000;92:780-781, 826- (per Reuters Health) 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.