2 AUGUST 2007
All things considered, the war against cancer is going better than that other war in progress at the moment -- even though cancer research gets a lot less money. Survival rates for many forms of cancer have been going up, and molecular biologists keep finding out more about the genetic conspiracies that induce cancerous cells to grow out of control.
Still, the cancer war is far from won. Some scientists think success would come sooner by forging a stronger alliance with China.
This alliance has nothing to do with poisoned dog food or DVD piracy. It would
be an alliance not with today's Chinese government, but with the 
Chinese sages
of ages past who rooted out a medicinal armamentarium from native Chinese plants.
Traditional Chinese medicine, focusing on the use of healing herbs, is still widely practiced in China, especially in rural areas. While modern Western medicine has invaded Chinese cities, plant extracts remain an important source of therapeutic drugs even in urban hospitals.
That should not be surprising -- after all, herbology is not magic (except, of course, at Hogwarts). Many of the drugs used in Western medicine originated from molecules found in plants or from other natural sources (such as insects or minerals). "Half of all anti-cancer drugs approved internationally between the 1940s and 2006 were either natural products or their derivatives," Thomas Efferth of the German Cancer Research Center in Heidelberg and collaborators write in an article to appear in Trends in Molecular Medicine.
In fact, plants make many more drugs than you'll find at Walgreens or CVS. Plants need to defend themselves against disease, too -- not to mention insects and parasites. So plant chemical weaponry has evolved to be pretty sophisticated, and recent research suggests that some of those weapons might be useful in fighting human cancer. Using plants to provide new drugs, or at least the starting materials for designing new drugs, has thus become more popular, leading to more interest in the
old Chinese methods.
To be sure, traditional Chinese medicine differs from the Western World's approach. For one thing, Chinese treatments are "holistic," based on the health of the whole body. Western doctors are generally more interested in the specifics of the disease, preferring the molecular battlefront where drugs and pathogens tangle atom-a-atom.
Another difference is the Chinese preference for a mixture of herbs, rather than single pure drugs. When the herbs work, it is hard to know which ingredient in which herb was the source of the benefit. And sometimes the other herbs may have provided additional help, perhaps boosting the effectiveness of the primary active ingredient or countering that substance's side effects.
Nevertheless, Chinese medicine sometimes works. So scientists are now exploring the anti-cancer properties of many traditional Chinese herbal preparations.
The goal is finding weapons that can attack cancer where it is vulnerable. Cancer's strategy is to unleash cell division, so that cells multiply uncontrollably, forming tumors. And then cancerous cells escape from the original tumor and spread to other parts of the body, initiating more tumor growth. Anti-cancer drugs might attack DNA, where the initial order for a cell to divide originates, or they might attack protein molecules involved in implementing cell division. Other natural drugs can help a damaged cell, destined to become cancerous, to commit suicide.
A drug from the Madagascar periwinkle, for instance, blocks the assembly of tiny microtubules, which provide a scaffolding for the separating and recombining of chromosomes when a parent cell divides to form two daughters. The assembly and disassembly for this purpose must be kept in balance; when a drug disturbs that balance, the cell commits suicide rather than embark on the road to tumor growth.
Numerous other plant-derived drugs have the ability to attack cancer's weak points. Derivatives of one chemical, from the Chinese "happy tree" Camptotheca acuminate, are already being used to treat ovarian and colon cancer. Artesunate, derived from molecules in the Chinese plant Artemisia annua (aka sweet wormwood), fights tumors with the advantage of evading some cancer cell counterattacks that render them resistant to many other drugs. Homoharringtonine, found in various Chinese evergreen shrubs, seems especially good at killing cells in leukemia.
In short, plants offer a lot of promise for combating cancer. And so far only about 5,000 plant species have been seriously studied for their anti-cancer chemistry, leaving perhaps 250,000 more species to explore.
Yet the natural product approach to cancer has its problems. Natural chemicals are still chemicals; if they have the power to cure, they have the power to kill. A good deal of artificial human chemistry may be needed to tweak the molecules that nature provides in order to focus their attack on cancerous cells while sparing those that are healthy.
In other words, winning the war on cancer will need to involve cooperation -- the molecular methods of modern Western science collaborating with the ancient wisdom of Chinese herbology. It just could become the coalition that sends the same message to cancer that Harry Potter sent to Voldemort.
E-mail: tsiegfried@nasw.org
