> Quoting April's article
For some tailored medicine for cancer does already exist. A breast cancer drug called Herceptin is already known to work in patients with an overactive HER2 gene.
A knowledge of the genetic basis behind a cancer means that it can potentially be attacked more specifically. For example, in the breast cancers that overproduce HER2, a monoclonal antibody has been developed that causes selective killing of cancer cells, without affecting normal cells which do not overproduce HER2.This extraordinary technology will gradually become commonplace, enhancing the efficacy of some drugs, minimising side effects of others (familiar to anyine being treated for aspergillosis), cutting waste of drugs that will be ineffective in some people and in the above case enabling the use of specialised drugs that will only be active in a specific group of patients - perhaps eventually down to the individual level in some cases.