

Study linking GM maize to rat tumours is retracted - feelthepain
http://www.nature.com/news/study-linking-gm-maize-to-rat-tumours-is-retracted-1.14268

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ryanatkn
Seems the main criticism is sample size - what was it?

> showed “no evidence of fraud or intentional misrepresentation of the data”,
> said a statement from Elsevier, which publishes the journal. But the small
> number and type of animals used in the study means that “no definitive
> conclusions can be reached”.

The type of animal is the same as used in the compared Monsanto study, so that
seems shaky.

~~~
grammaton
For starters, the breed of rat used - Sprague-Dawley - is one that routinely
develops cancer and tumors, and is, in fact, used in cancer research for
exactly this reason. So the fact that they developed tumors is about as
surprising as a sunrise, and the study in question did not have any controls
or statistical compensation whatsoever for this fact. Then, of course, there's
also the sample size.

~~~
josephlord
[http://ac.els-
cdn.com/S0278691512005637/1-s2.0-S027869151200...](http://ac.els-
cdn.com/S0278691512005637/1-s2.0-S0278691512005637-main.pdf?_tid=031027b4-5914-11e3-8060-00000aab0f26&acdnat=1385743003_c29458b2a2716542f38d07dcb7c8f5c9)

I haven't read the full paper but the abstract does mention controls. I have
no idea if they were for some reason inadequate or there were methodological
errors but you are incorrect to say that there were no controls.

~~~
grammaton
Let me rephrase: by control, what I mean is not "control group," but
"statistical control." Their statistical analysis did not properly account for
the immensely increased likelihood of cancers given the breed of rat they
chose.

~~~
darkmighty
From their abstract, they don't cite the breed of mice they use, but they do
cite that control groups had tumors and cites the tumor rate as compared to
control in addition to absolute rates. To me that makes this a non-issue
considering the target audience.

~~~
grammaton
Stop reading the abstract and _go read the paper._

"but they do cite that control groups had tumors"

Yes, of course they did - they were the same breed of rat, and as I've already
mentioned, they almost invariably get tumors.

"cites the tumor rate as compared to control in addition to absolute rates"

So what? The problem is that with a single trial, and such a small sample
size, there is _no evidence that any differences in observed cancer rates were
not simply due to random variation._

"To me that makes this a non-issue considering the target audience."

No offense, but no one really cares how it seems _to you._ The whole purpose
of the scientific method is to get around individual biases. And what do you
mean by "the target audience?" What does that have to do with anything? It
doesn't matter who the target audience is - that doesn't excuse a poorly
designed study. Seralini's study had a small sample size - one sixth the
minimum recommended by accepted guidelines for studies of this type using this
kind of animal. He's repeatedly refused to make his full data set publicly
available. There's some evidence that rat feed may have been contaminated with
GMO derived soy products, which would, of course, invalidate the results
completely. There's also some question of multiplicity effects as well. In
short, there are plenty of problems with this study, and your cursory
examination of an abstract isn't going to dig up some smoking gun that
invalidates all of the well deserved criticism.

------
lukeman
Maaize… ohhhh.

