THE NEW CANCER FIGHTERS.

This article focuses on the development of drugs and therapies to fight cancer. There are more than 200 different types of cancer affecting humans, and scientists expect no single cure will ever be found. In 1998, Patrick Lee, working out of the University of Calgary, published a groundbreaking study which showed that a common cold virus, called the reovirus, is capable of killing cancer cells. In the process, he helped open what is fast becoming the newest front in the war against one of the world's most deadly diseases. The problem is it takes only a small amount of virus to cause a cold, but, to treat cancer, hundreds of millions of viral particles have to be injected into the bloodstream or the tumour itself. On the survival front, the broad prognosis today is much improved over a generation ago, especially for women with breast cancer and men with prostate cancer, two of the most common forms of the disease. The same holds true for a variety of other cancers, including melanoma, Hodgkin's disease and cancer of the uterus, cervix, thyroid, testis and male bladder. There are only a handful of these medications approved for clinical use in Canada, though others are being tested in trials. Iressa, as well as earlier drugs like Gleevec (for chronic myeloid leukemia), target a chemical receptor called EGFR that helps the cancerous cell grow and spread. Herceptin, also a targeted monoclonal antibody, is used to treat breast cancer. However, in 2000, Genentech, Herceptin's manufacturer, wrote health-care providers to warn them of 62 post-marketing reports of serious adverse reactions, including 15 patients who died, some after experiencing an acute reaction in their lungs. INSETS: TRACKING TUMOURS WITH A FORENSIC MIND;THE ODDS;THE BIG ONES;BREAKING THE CHAIN