Update: 22.07.2008
Tobacco 'could help treat cancer'
The tobacco plant - responsible for millions of cancer cases - may actually offer the means to treat one form of the disease, a study suggests.
US scientists used the plant to "grow" key components of a cancer vaccine.
The National Academy of Sciences study suggests they could be used to tackle a form of lymphoma.
UK specialists said while "potentially exciting", more research would be needed to test how well the vaccine actually worked.
The ironic new role for tobacco is the work of researchers from Stanford University in California.
They are using the plants as factories for an antibody chemical specific to the cells which cause follicular B-cell lymphoma, a type of non-Hodgkin's lymphoma.
These antibodies are put into a patient newly-diagnosed with the disease, to "prime" the body's immune system to attack any cell carrying them.
If successful, this would mean the body would then recognise and destroy the lymphoma cells.
However, every patient's antibodies are different, and would need to be produced quickly once the diagnosis was made.
The idea is not a new one - attempts have already been made to grow these antibodies inside animal cells, with mixed success.
However, a plant-grown vaccine would be much cheaper and in theory could carry less risk to the patient, as animal cells might hold unknown viruses.
So far, the experimental vaccine has only been tested on a handful of patients to check for any side-effects of using plant-produced antibodies, so its effectiveness at fighting the disease is uncertain.
'Infected' plants
Dr Ronald Levy, who is leading the research, said: "It's pretty cool technology - and it's really ironic that you would make a treatment for cancer out of tobacco. That appealed to me."
The technique is relatively straightforward. Once a patient's cancer cells are isolated in the laboratory, the gene responsible for producing the antibody is extracted and added to the "tobacco mosaic virus".
The plants are then "infected" with the virus, and as it spreads through the cells, the added gene starts the process of producing large quantities of the antibody.
After just a few days a few leaves are taken, ground up, and the antibody extracted from them.
Only a few plants are needed to make enough vaccine for a patient.
Professor Charles Arntzen, from Arizona State University, said that the sheer speed of the production process could convince patients to wait for their own tailored vaccine rather than undergoing other treatment.
A spokesman for Cancer Research UK, said: "While these results could potentially be very exciting, this was a small and early-stage trial and it did not look at whether this vaccination strategy reduced the size of the tumours."
"This is a good foundation for future work, but a larger study will be needed to test the success of this plant-made antibody in fighting non-Hodgkin's lymphoma."
Smoking causes up to 30 percent of cancer deaths in the United States and Canada, making tobacco smoke the most lethal carcinogen in North America. Smoking is associated with cancer in the lungs, esophagus, respiratory tract, bladder, pancreas, and probably cancers of the stomach, liver, and kidneys. The risk of cancer increases depending on the number of cigarettes smoked per day, the cigarette’s tar content, and how many years a person smokes. Starting to smoke while young significantly increases the risk of developing cancer.
Each year in the United States, about 3,000 nonsmoking adults die of lung cancer caused by exposure to the smoke of others’ cigarettes, called secondhand smoke or environmental tobacco smoke. Nonsmoking spouses of smokers are 30 percent more likely to develop lung cancer than those married to nonsmokers. Breathing secondhand smoke also increases the risk of cancer in the children of smokers and in nonsmokers who work in smoky places, such as restaurants and bars.
Cigars, pipes, and smokeless tobacco have also been implicated in increased risk for cancer. Cigars contain most of the same cancer-producing chemicals as cigarettes, and people who smoke cigars have a 30 percent higher risk of developing cancer than nonsmokers. Oral cancers occur more frequently in people who use smokeless tobacco, or snuff. Snuff users, for example, are 50 times more likely to develop cancers of the cheek or gum than nonusers.
|
