When does ambition or the will to believe begin to look more like fraud?
The biggest criticism from both reviews is that Seralini and his team used only ten rats of each sex in their treatment groups. That is a similar number of rats per group to that used in most previous toxicity tests of GM foods, including Missouri-based Monsanto's own tests of NK603 maize. Such regulatory tests monitor rats for 90 days, and guidelines from the Organization for Economic Co-operation and Development (OECD) state that ten rats of each sex per group over that time span is sufficient because the rats are relatively young. But Seralini's study was over two years --- almost a rat's lifespan --- and for tests of this duration, the OECD recommends at least 20 rats of each sex per group for chemical-toxicity studies, and at least 50 for carcinogenicity studies.
Moreover, the study used Sprague-Dawley rats, which both reviews note are prone to developing spontaneous tumors. Data provided to Nature by Harlan Laboratories, which supplied the rats in the study, show that only one-third of males, and less than one-half of females, live to 104 weeks. By comparison, its Han Wistar rats have greater than 70% survival at 104 weeks, and fewer tumors. OECD guidelines state that for two-year experiments, rats should have a survival rate of at least 50% at 104 weeks. If they do not, each treatment group should include even more animals --- 65 or more of each sex.
''There is a high probability that the findings in relation to the tumor incidence are due to chance, given the low number of animals and the spontaneous occurrence of tumors in Sprague-Dawley rats,'' concludes the EFSA report. In response to the EFSA's assessment, the European Federation of Biotechnology --- an umbrella body in Barcelona, Spain, that represents biotech researchers, institutes and companies across Europe --- called for the study to be retracted, describing its publication as a ''dangerous case of failure of the peer-review system.."
Yet Seralini has promoted the cancer results as the study's major finding, through a tightly orchestrated media offensive that began last month and included the release of a book and a film about the work. Only a select group of journalists (not including Nature) was given access to the embargoed paper, and each writer was required to sign a highly unusual confidentiality agreement, seen by Nature, which prevented them from discussing the paper with other scientists before the embargo expired.
Hyped GM maize study faces growing scrutiny [Oct 2012]