Did Dr Hayes misunderstand or misrepresent Séralini’s study in claiming the authors made a "definitive" link to cancer? No such claim is in the paper and the word “cancer” does not appear in the paper.

On 10 December 2013 Dr Hayes defended his decision to retract the Séralini study in a published statement[1] which appeared to contradict his previous statement[2] in which he wrote that the results reported in the Séralini study were “not incorrect”. In his more recent justification, Dr Hayes wrote that the retraction was in line with COPE guidelines, since the study was an example of unreliable findings due to “error”. Specifically, he wrote:

“The data are inconclusive, therefore the claim (i.e., conclusion) that Roundup Ready maize NK603 and/or the Roundup herbicide have a link to cancer is unreliable… it is the entire paper, with the claim that there is a definitive link between GMO and cancer that is being retracted.”

This statement is problematic from two points of view.

First, Dr Hayes wrongly attempts to equate inconclusiveness with error. The two concepts are not synonymous. And while error may in some cases be grounds for retraction, inconclusiveness is not.

Second, Dr Hayes misunderstands or misrepresents Séralini’s study. The authors never inferred or claimed that the GM maize NK603 and/or the Roundup herbicide had a “definitive link” to “cancer”. In fact, they do not even use the word “cancer” in the paper, though some of the analyzed tumours are identified as being of cancerous types and a few are identified as metastatic.

Instead, Séralini’s team simply observed and recorded the rate and timing of tumours (which are not, by definition, synonymous with “cancer”) in the various groups of animals. This is in line with the internationally accepted norm of the OECD chronic toxicity guideline 452, which requires that in a chronic toxicity study, all “lesions” (which would include tumours) are recorded.[3] According to this OECD standard, it would be scientifically reprehensible, even fraudulent, to ignore the tumours.

An objective reading of the paper would show the care taken by the authors to avoid definitive claims. Instead they recommend that further studies should be carried out. The only person claiming definitiveness in the Séralini paper is Dr Hayes.

Dr Hayes does not, however, specify any unjustified or “definitive” claims in the published study. Under the guidelines of the Committee on Publication Ethics (COPE) to which FCT subscribes, the editor could request the authors to publish a correction or clarification of any specific unjustified claims.[4] Even if such claims had somehow escaped the attention of the peer reviewers and were identified, however, this would not be grounds for retraction.


[1] Hayes AW (2013). Food and Chemical Toxicology editor-in-chief, A. Wallace Hayes, publishes response to Letters to the Editors. 10 Dec. http://www.elsevier.com/about/press-releases/rese...

[2] Hayes AW (2013). Letter to Professor GE Séralini. 19 Nov. Available at: http://www.gmwatch.org/files/Letter_AWHayes_GES.p...

[3] Organisation for Economic Cooperation and Development (OECD) (2009). OECD guideline no. 452 for the testing of chemicals: Chronic toxicity studies: Adopted 7 September 2009. http://bit.ly/LxJT1Z

[4] COPE (2009). Retraction guidelines. http://publicationethics.org/files/retraction%20g...

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