In 2012, Séralini et. al. published their study (Long term toxicity of a Roundup herbicide and a Roundup-tolerant genetically modified maize) claiming to show an association between cancer in rats and corn genetically engineered to be resistant to glyphosate (including some groups to which he actually fed glyphosate). The scientific community at large quickly condemned the study due to numerous obvious failures in its methods, and the Wakefieldian, (Or Ponz and Fleschmannian if you prefer) style of the researchers in manipulating the press before the scientific community at large had a chance to evaluate the study.
Let’s revisit some of that criticism, shall we?
From Dr. Lúcia de Souza and Dr. Leila Macedo Oda, Vice-President and President of the Brazillian National Biosafety Agency:
These animals were maintained for 24 months and fed ad-lib. This specific breed of rats is well known to be prone to develop cancer with age and especially when there is no dietary restriction.
[...]the authors seem to consider the bits that supported their own beliefs and forgot to question their own contradicting results. [...] Actually, due to the high incidence of spontaneous cancer under the conditions of the study, any conclusion based on such a small group is basically impossible.
From Prof. Peter Langridge at Australian Centre for Plant Functional Genomics
There are other confusing sentences that also reflect poor editorial work, for example “Up to 14 months, no animals in the control groups showed any signs of tumors whilst 10–30% of treated females per group developed tumors, with the exception of one group (33% GMO + R).” I was left wondering if anyone had really read the paper carefully.
At the scientific level there are also major problems with this manuscript. These problems include: the absence of any statistical analysis of the data, the peculiar treatment of controls, the biased interpretation of the results (for example, the males feed high doses of GM maize appeared to show reduced tumour rates but this is ignored [albeit without statistical assessment]) and the failure to adequately reference other studies that have reached different conclusions.
from Dung Le Tien and Ham Le Huy, Agricultural Genetics Institute, Pham Van Dong Str., Hanoi, Viet Nam:
…we would like to call on your action to request a complete release/publication of the data from the authors of Seralini et al. for a rigorous re-evaluation and if further supporting ground could not be established, an editorial retraction must be made.
from Professor Sir Colin Berry MD, DSc , Emeritus Professor of Pathology at Queen Mary College, London:
No images of tumours in control animals are shown and the illustrations in test animals appear typical for aged SD rats (although they would not normally be allowed to be so badly affected before termination, on ethical grounds, in most laboratories where I have worked).
What, precisely, is tested? There are no data on diet composition, nothing to ensure an attempt at iso-caloric matching and no information on homogeneity, stability or concentration of glyphosate in drinking water formulations. The actual doses of GM maize and glyphosate consumed are not reported.The dietary incorporation rate reported for the GM maize of 11%, 22% or 33% is a quantitatively surprising statement since PCR measurements can barely distinguish between 11% and 22%, or between 22% and 33% trait.
from Prof. Anthony Trewavas FRS:
Seralini’s whole results depend totally on an inadequate number of control rodents. To do this research properly several thousand rodents at least would be needed. There is nothing in these results except random error and any competent referee would have picked up that immediately.
I also question the absence of control photographs and whether it is ethical to keep rodents in those conditions just to provide pictures that can be used as frankly nothing more than propaganda. Science requires the dispassionate presentation of information-this paper and this journal have dealt the value of evidence-based knowledge a serious blow and it can only be rectified if the paper is withdrawn by the authors with an apology for misleading the public and the scientific community alike.
From Frederic Schorsch’s paper, entitled: Serious inadequacies regarding the pathology data presented in the paper by Séralini et al. (2012)
This article attracted great attention within the scientific and regulatory community. Substantial gaps in the study design, fundamental flaws in the data analysis and erroneous interpretation of results have been pointed out by individual scientists and administration bodies. Upon request by the European Commission, the European Food and Safety Authority (EFSA) reviewed the study and concluded that the design, reporting and analysis of the study as presented in Food and Chemical Toxicology are inadequate and that this contribution is of insufficient scientific quality to be relevant in the safety assessment process
From the European Food Safety Authority:
Considering that the study as reported in the Séralini et al. (2012) publication is of inadequate design, analysis and reporting, EFSA finds that it is of insufficient scientific quality for safety assessment. Therefore, EFSA concludes that the Séralini et al. study as reported in the 2012 publication does not impact the ongoing re-evaluation of glyphosate, and does not see a need to reopen the existing safety evaluation of maize NK603 and its related stacks. EFSA will give the authors of the Séralini et al. (2012) publication the opportunity to provide further information on their study to EFSA.
Kritisiert wird an der Studie insbesondere die zu kleine Anzahl an Tieren pro Gruppe, die nicht den international anerkannten Standards für Langzeitstudien entspricht.
[ This study was criticized especially for its small count of animals per group, which doesn't reflect the international recognized standards for long term studies. ]
Additional links to stories about how this study was a massive disgrace:
From Darwinius to GMOs: Journalists Should Not Let Themselves Be Played – Carl Zimmer, The Loom
One sees several common threads in discussion about this paper, most notably the laughably small sample size for each group (10). The writers maintain that their sample size was okay because that’s what Monsanto used in their study… which makes absolutely no sense to me. If you really wanted to prove a real effect, why not do a better study than Monsanto did instead of doing a similarly crappy one?
Also brought up are the ethics in letting the mice live longer than research like this normally should, in order to get propaganda photos, (which have been used to great effect on pseudoscience-supporting anti GE misinformation mills like Natural News and INFOwars. ) statistical games and omissions, and reporting results not consistent with their own data which is plainly in the same paper.
In short, this paper is completely useless as anything other than an example of bad, biased science and how the scientific consensus works. Anyone linking to it as proof of anything in a discussion probably has no idea what they’re talking about.