NEW YORK -- Scientists who reported that they'd found a startlingly simple way to make stem cells withdrew that claim Wednesday, admitting to "extensive" errors in the research.
In two papers published in January in the journal Nature, the Japanese and American researchers said that they'd been able to transform ordinary mouse cells into versatile stem cells by exposing them to a mildly acidic environment. Scientists hope to harness stem cells to grow replacement tissue for treating a variety of diseases.
While scientists have long been able to perform such transformations with a different method, the newly reported technique was far simpler, and the paper gained wide notice - and some skepticism - in the research community. It was also widely reported in the media, including by The Associated Press.
But before long, the government-funded Riken Center for Developmental Biology in Japan accused one of its scientists, Haruko Obokata, of falsifying data in the research. Obokata, the key author of the papers, defended the results during a televised news conference in April while apologizing for using wrong images in the published reports.
On Wednesday, Nature released a statement from Obokata and the other authors of the papers that withdrew the papers. The scientists acknowledged "extensive" errors that meant "we are unable to say without a doubt" that the method works. They noted that studies of the simpler method are still going on by other researchers.
Dr. Charles Vacanti of Brigham and Women's Hospital in Boston, another main author, issued a separate statement in which he said he believes the further studies will vindicate the method, which produced what the authors called STAP cells.
But another author, Yoshiki Sasai, deputy director of the Riken center, said the errors in the papers meant "it has become increasingly difficult to call the STAP phenomenon even a promising hypothesis." In a statement issued by Riken, he said he was "deeply ashamed" of the problems in the papers.
Retractions of papers in major scientific journals like Nature are rare. They can come about because of fraud or the discovery of honest mistakes that undercut the conclusions of research. Publications like Nature routinely have experts review papers submitted by scientists to look for problems. But in an editorial released Wednesday, Nature concluded that its editors and reviewers "could not have detected the fatal faults in this work."
Still, the journal said it is reviewing its practices.