How to report in vitro cancer studies: maitake mushroom extract doesn't "fight cancer"

ResearchBlogging.orgEarlier this week, I saw one of the best treatments of a misinterpreted story that has me thinking about how all news outlets should report in vitro laboratory studies.

Only thing is that it didn't come from a news outlet.

It came instead from a brainwashing site run by those medical socialist types - I am, of course, speaking of the UK National Health Service and their excellent patient education website, NHS Choices.

You may recall reading in the popular dead-tree or online press that investigators from New York Medical College in Valhalla published in British Journal of Urology International about maitake mushroom extract killing bladder cancer cells. The most widely cited reports came from the UK Daily Mail by Tamara Cohen entitled, "Mushroom 'shrinks cancer tumours by 75 percent,'" and "Cancer Cure: Mushrooms Can Shrink Tumors," by Jo Willey of the UK Daily Express.

Well, NHS Choices took a look at the study and detailed how the mushroom extract was only used on bladder cells in culture. Throughout their review and in the conclusion that follows, they specifically took to task the story in the Daily Express:

The findings of this study should be considered as preliminary ones that may lead to further research.

The findings that a combination of interferon alpha (a common immunotherapy for bladder cancer) and the PDF extract can reduce bladder cancer cell growth in a laboratory setting are the first step towards future studies. However, the potential benefits of PDF as a combination treatment for bladder cancer will only be established through studies to fully assess toxicity and longer-term benefits and harms. Investigating new treatments in this way is often a lengthy process, usually beginning with animal studies and only later followed by human studies.

It is too soon to claim, as the Daily Express has, that maitake mushrooms are a cure for cancer. The substance tested was only a chemical extract of the mushrooms, and this study provides no evidence that either the extract or the mushrooms themselves have health benefits in humans. People should resist the temptation for people to eat large amounts of mushrooms if they develop bladder cancer, as it is not clear from this research if any potentially active ingredients can even be absorbed through digestion. It is also unclear whether the effects of high doses in humans are harmful.

In fact, it's even worse than that. The mushroom extract only killed bladder carcinoma cells in culture following a 72 hr exposure at concentrations of 400 and 700 μg/mL, with only about 53% cell growth inhibition at the highest concentration. The 75% number came from the degree of growth inhibition by the maitake extract at 200 μg/mL together with 10,000 U/mL of interferon-α2b.

These are extremely high concentrations of a natural product extract, even when one considers that the cytotoxic or cytostatic compound(s) in the mushroom might be present at very low concentrations. Most natural products studies in the literature usually establish a cutoff of activity at 5 or 20 μg/mL and some even consider that level to be overly optimistic. Therefore, the long-term importance of this work will require some isolation and characterization of these compounds before one would even consider embarking on further studies for selective toxicity and effectiveness in animal models of human bladder cancer, much less clinical trials in patients with bladder cancer.

But I point out this post from NHS Choices not only because they criticize the irresponsible overinterpretation of scientific results in the popular press. Instead, I wanted to point out how they presented the story. (And I wish I knew the name of the author(s) so I could give them proper personal credit.).

The article starts with the title, "Mushroom extract 'fights cancer,'" to be sure to draw in search engine hits using keywords also used by the misleading stories. The article then presents the representation of the work by the Daily Express. . .

The Daily Express has reported this study poorly and has made claims that are not supported by this piece of research. The newspaper does not make it clear that this was a laboratory study, and its description of the study methods is not consistent with the research itself.

. . .and then takes it apart systematically, clearly, and concisely, using the following headers:

  • Where did the story come from?
  • What kind of research was this?
  • What did the research involve?
  • What were the basic results?
  • How did the researchers interpret the results?

This logical approach makes it easy for someone with average intelligence, especially a patient or family member interested in bladder cancer treatments, to understand the real facts of the study. The text is neither too dense nor too lengthy, yet still gets the keys points across.

The writer(s) then concluded with two links:

  • Links to the headlines
  • Links to the science

I was ecstatic to see the link directly to the abstract at the journal website. Unfortunately, this is not an open-access journal and many readers, even those at some academic institutions, might not have subscription access to the full paper. But at least the article provides one with the direct hyperlink to the primary source.

I know that dead-tree editors might say that doing so would clutter up a print story. But why could this not become common practice for any online press portal?

I thank the good people at NHS Choices for giving us a good example of how to do it right. I only hope that when all Americans are given the opportunity for basic health care that our agencies will be as informative.

In the meantime, I shall look to enjoy maitake mushroom extracts in this form (with other mushrooms, too!):

Thumbnail image for Maitake soup Tiny Urban Kitchen.jpg

Photo credit: Tiny Urban Kitchen blog by Jen, a chemist from Cambridge, MA.

Louie, B., Rajamahanty, S., Won, J., Choudhury, M., & Konno, S. (2009). Synergistic potentiation of interferon activity with maitake mushroom d-fraction on bladder cancer cells BJU International DOI: 10.1111/j.1464-410X.2009.08870.x


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Unfortunately a company selling untested and unproven mushroom extracts is the first hit you get when you google "canine cancer" for only a few hundred dollars a month you can prevent, or treat, or immunomodulate, or something, for just about all the most common types of canine cancer.
I posted about it earlier this year.

They seem to be shamelessly exploiting desperate pet owners, and I should not be surprised, but it is difficult to deal with at times.

On the other hand, I enjoy some mycophagy myself, and found some nice oyster mushrooms in the woods this fall. Too bad the monsoon in AZ was weak this year-not enough moisture for chanterelles!

Great post- will share.

@DVMKurmes - I'm learning a lot more about marketing to pet owners these days so that doesn't surprise me. You're taunting me with the beauty of Arizona, though.

@anjou - thanks very much. Was thinking of you today as I listened in via conference call on Erleichda's legendary wisdom for our program project progress meeting. I miss him a ton.

Didn't mean to taunt, and you have an open invitation to dinner if you are ever in the area.
I plan to bookmark this post for future reference as well.

By DVMKurmes (not verified) on 04 Dec 2009 #permalink

unfortunately, excessive interpretation of preliminary results by the media just adds fuel to the public-confusion fire. yes, we should by all means share interesting results that are funded with public dollars with the public. but in a way that the public understands what it realistically tells us. by making such exaggerated claims, it seems to me we're almost setting the general audience up for disappointment.

i had someone arguing vehemently with me recently using news stories of scientific research, and all i could argue back was "but that's not what the data said!"
i was, of course, not sufficiently convincing over Obscure News Outlet Website. /facepalm

Erleichda was hoping you'd be there live, up close and personal instead of via conference call. He enjoyed the meeting.

I'm almost certain that claiming to have a 'cure for cancer' is illegal. The Express might have found a loophole by claiming to be 'reporting' rather than saying that they're discovered it themselves but still, that's not just professionally unsound, it's ethically unsound as well.

Pharmaboy: Indeed, missed you at the meeting. Next one. Deserving applause to NHS Choices for their handling of the mushroom report.

By Erleichda (not verified) on 06 Dec 2009 #permalink