“An exotic mushroom could help in the fight against cancer”, the Daily Mail reported today. It said that tests show that extracts from a yellow tropical fungus, Phellinus linteus (PL), can stop blood vessels from growing and feeding breast, prostate, skin and lung cancers. It continued that studying the fungus may lead to the development of new anti-cancer drugs. It reported that the researchers believe that the mushroom extract could be used as a dietary supplement to ward off cancer in healthy individuals.
It is too early to say whether this mushroom extract will have a future role in anti-cancer treatment or whether it would be beneficial as a health supplement. As the lead researcher warned, people should not consider buying the extract until further tests demonstrate it to be safe and effective. Much further research is needed to answer this question.
Where did the story come from?
Dr D Sliva and colleagues from the Cancer Research Laboratory at the Methodist Research Institute and the Department of Medicine at Indiana University, Indianapolis, USA, carried out the research.
The study was funded by the Methodist Health Foundation, the Department of the Army Medical Research and Materiel Command, the Breast Cancer Research Training Program and by Maitake Products Inc.
The study was published in the peer-reviewed: British Journal of Cancer.
What kind of scientific study was this?
In this experimental study, the researchers aimed to demonstrate the antitumour mechanisms that occur with the mushroom Phellinus linteus (PL) – a mushroom occurring in tropical regions - and how it acts to prevent the invasive behaviour of cancer cells.
The researchers investigated the effects of PL extract on highly invasive breast cancer cells. Two types of breast cancer cells were prepared on culture plates in the laboratory and incubated in appropriate conditions. The researchers then examined how the cells grew, how they formed colonies, their life cycle, and their invasive behaviour. The cancer cells’ invasive behaviour was assessed by how they attached to certain proteins, how they migrated, and how they invaded a gel that the researchers used to mimic human tissue. This was tested on untouched cells and cells that had been treated with PL extract.
The researchers also looked at whether PL extract could inhibit new blood cell formation, and at how PL extract affected the breast cancer cells’ production of growth factors that stimulate the formation of new blood vessels.
The researchers carried out statistical comparisons of these measures of breast cancer cell growth in the control group of untouched cells and the cells that had been treated with different doses of PL extract.
What were the results of the study?
The researchers found that PL extract suppressed the growth and colony forming behaviour of highly invasive breast cancer cells grown in the laboratory. The scale of the effect was found to be dependent on the size of the dose and length of exposure, with the greatest effect being at highest concentration and with the longest period in incubation. The effects of the mushroom extract on the growth of less invasive breast cancer cells were more pronounced.
PL extract also reduced the invasive behaviour of one type of breast cancer cell by suppressing its release of a certain growth substance. It was found that the early growth of the blood vessels that feed cancer cells was prevented by PL extract both directly and by preventing the cells from secreting a vascular growth factor. The researchers found evidence that this was achieved partly by inhibiting the action of a certain enzyme (AKT) in the breast cancer cells.
What interpretations did the researchers draw from these results?
The researchers say that they have demonstrated that PL extract inhibits cell growth and colony formation of highly invasive breast cancer cells and acts to prevent the formation of new blood vessels.
They say their results suggest a potential therapeutic benefit of PL extract as a natural compound in the treatment of invasive breast cancer. However, they say that further studies in animals and patients will be needed to evaluate these effects.
What does the NHS Knowledge Service make of this study?
These are early experiments examining the effects of an extract from the mushroom Phellinus linteus on invasive breast cancer cells. Much further research would be needed in the laboratory and in animals before this extract could be considered for testing in humans.
At present, it is unclear if the treatment could be used to treat cancer. The extract was applied directly to the cancer cells, and it is not known if the effects would be the same if the extract was delivered through other routes (e.g. orally).
It is also unknown if the PL extract has any short or long term adverse effects. A careful risk and benefit analysis would be needed before this extract could be considered for use in humans.
It is too early to say whether this mushroom extract will have a future role in anti-cancer treatment. As the lead researcher warned, people should not consider buying the extract until further tests demonstrate it to be safe and effective.
Analysis by Bazian
Edited by NHS Website
Links to the headlines
Metro, 16 April 2008
Daily Mail, 16 April 2008
Links to the science
Br J Cancer 2008; 98:1348-1356