Two scientific papers that initially electrified biologists by describing an easy way to make stem cells were retracted on Wednesday by the journal that published them after they were found to be riddled with “critical errors.”  The papers, published in Nature in January, were a source of pride in Japan, where much of the research had been done in the government-backed Riken Center for Developmental Biology. The lead scientist, Haruko Obokata, became an instant celebrity.  But pride soon turned to embarrassment as one error after another came to light, and an internal investigation by Riken concluded that Ms. Obokata had misrepresented or altered images.  So far, independent scientists have not reproduced the work described in the papers, raising substantial doubts about whether the simple way to produce stem cells really exists.  “We apologize for the mistakes,” the authors of the two papers wrote in a retraction.  “These multiple errors impair the credibility of the study as a whole, and we are unable to say without doubt whether the STAP-SC phenomenon is real,” they wrote. “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.”  STAP-SC stands for stem cells resulting from stimulus-triggered acquisition of pluripotency. The researchers reported in January that regular cells taken from the body could be turned into stem cells by simply exposing them to stress, as by dipping them in an acid bath.  That seemed to provide an easy way to create multipurpose stem cells that could then be turned into different types of tissues, which might one day be used to treat diseases or repair injuries.  The retraction notices listed five errors that were not previously disclosed in the Riken investigation. Most of them were that images in the papers did not show what they were said to have shown. One error was that cells used in a crucial experiment did not match the mice from which the cells were supposed to have been taken.  While many of the authors of the work at Riken had previously agreed to a retraction, one holdout had been Dr. Charles A. Vacanti of Harvard University and the Brigham and Women’s Hospital, who had been Ms. Obokata’s supervisor when she was a graduate student in his laboratory and was the senior author of one of the papers.  In a statement Wednesday, Dr. Vacanti said he was “deeply saddened by all that has transpired, and after thoughtful consideration of the errors presented in the Riken report and other concerns that have been raised, I have agreed to retract the papers.”  He said that he was still hopeful that the concept of STAP cells, which he and his brother Martin had initially hypothesized, would eventually be verified.  Riken is now trying to see if it can replicate the work and prove the existence of STAP cells. Japanese news media reported that Ms. Obokata, who has denied charges of misconduct, would work on that effort for several months, with everything she does being video-recorded.  In an editorial, Nature said it had concluded that its editors and the outside scientists who had reviewed the papers before publication “could not have detected the problems that fatally undermined the papers.” It said the reviewers “quite rightly took on trust what was presented in the papers.”  Nonetheless the editorial said the episode had “further highlighted flaws in Nature’s procedures” and sloppiness among scientists. It said steps were being taken to improve the rigor of reviews of submitted papers.  A version of this article appears in print on July 3, 2014, on page B2 of the New York edition with the headline: Stem Cell Research Papers Are Retracted. Order Reprints|Today's Paper|Subscribe
The journal Nature said the papers — which detailed an easy way to create stem cells — were error-filled and had not been verified by anyone else.