Tests during the past 2 decades have indicated that retinoic acid can retard and even reverse some aberrant cell growth, a property that makes it remarkably effective against a deadly form of leukemia. The Food and Drug Administration approved that use of the compound, a chemical cousin to vitamin A, in 1995. Other tests have indicated it may also work against cancers of the mouth, skin, and lung.
Working with tumor cells, researchers in Austria now report that retinoic acid shows promise against breast cancer when introduced following a drug that thwarts a cell process called methylation. This one-two punch awakens a potent cancer-fighting gene called RAR-beta-2, which is found on chromosome 3, say the scientists.
Atom clusters called methyl groups often coat DNA. Such methylation seems to regulate certain genetic functions. When it runs amok, however, the process can silence DNA, keeping it from being transcribed into RNA to generate needed proteins. Indeed,