Japanese stem-cell 'breakthrough' findings retracted
Research into one of the biggest recent stem-cell "breakthroughs" has been withdrawn because of "critical errors".
Scientists in Japan had claimed stem cells could be made cheaply, quickly and ethically just by dipping blood cells into acid.
They have now written a retraction that apologises for "multiple errors" in their report.
Nature, the journal that published the findings, is reviewing how it checks scientific papers.
Stem cells can become any other type of tissue and are already being investigated to heal the damage caused by a heart attack and to restore sight to the blind.
Researchers around the world described the acid-bath stem-cell finds as a "game changer," "remarkable" and "a major scientific discovery".
However, errors were rapidly discovered, parts were lifted from early work and presented as though it was new research, and leading scientists have been unable to produce stem cells using acid in their own laboratories.
An investigation by the Riken research institute in Japan found that scientist Dr Haruko Obokata had fabricated her work in an intentionally misleading fashion.
The retraction states: "These multiple errors impair the credibility of the study as a whole and we are unable to say without doubt whether the stimulus-triggered acquisition of pluripotency stem cells phenomenon is real.
"Ongoing studies are investigating this phenomenon afresh, but given the extensive nature of the errors currently found we consider it appropriate to retract both papers."
The affair brings back memories of the false claims by world-renowned cloning scientists Hwang Woo-suk.
He claimed he had produced embryonic stem cells from cloned human embryos, but those findings were later found to be "intentionally fabricated".
A Nature editorial stated that the public's trust in science was at stake in the latest controversy.
It added: "Although editors and referees could not have detected the fatal faults in this work, the episode has further highlighted flaws in Nature's procedures and in the procedures of institutions that publish with us."
However, it did say a review was under way to increase checking on images used in papers.
The acid-bath stem cells research has not been completely discredited and research is continuing to see if stem cells can be produced using the method.
Chris Mason, a professor of regenerative medicine at University College London, originally said the results were "a very exciting, but surprise, finding" and added: "It looks a bit too good to be true."
After the retraction, he told the BBC: "I'm surprised that Nature took so long when there was so much material showing problems with the papers. I don't understand that."
However, he said the system of peer review, in which fellow scientists critique papers before they are published, would struggle to pick up the problems in this research.
He said: "If you're a reviewer you can only review the material you're given. You have to take it on trust. You're not a detective looking for fraud.
'Good day for science'
"If you have to act as a super-sleuth, that's impossible for anyone to ever do."
He praised the way social media had uncovered and shared the errors, which could have otherwise taken years to unpick.
"I would argue this is not an embarrassing day for science, I think it's a good day for science and it shows we work well to weed out inferior publications."
Dr Dusko Ilic, a senior lecturer in stem-cell science at King's College London, said: "It is easy to be judgmental, and pointing fingers after all is over.
"Gaining knowledge is difficult. It requires both time and persistence, I hoped that Haruko Obokata would prove at the end all those naysayers wrong.
"Unfortunately, she did not. The technology, indeed, sounded too good to be true, though I still find fascinating how a 30-year-old scientist could pass scrutiny of her co-workers and multiple reviewers in Nature with a complete fabrication."
The UK Medical Research Council's Prof Robin Lovell-Badge added: "The stem cell community has been expecting these retractions to come for a while.
"This story illustrates how the stem cell field can rapidly detect bad science and reject it.
"It also illustrates both the problems and benefits of hype, this was potentially important research because of the novelty of the claims in an important field, but it was hyped far beyond reality, by some of the authors and by their perhaps willing victims, the media."