A purported stem cell advance that generated both excitement and skepticism upon its announcement nearly a year ago—and gave rise to nagging questions, retractions of published articles, findings of scientific misconduct, and even a suicide in the months that followed—has now suffered what may amount to its ultimate debunking. The would-be breakthrough, called stimulus-triggered acquisition of pluripotency (STAP) cells, prompted a five-month-long replication attempt that failed, announced officials at the RIKEN Center for Developmental Biology in Kobe, Japan.
RIKEN scientist Haruko Obokata, who led the initial STAP studies, was among those attempting to replicate the work she and her colleagues described in a pair of articles that appeared in Nature. Obokata, professing confusion and dismay at having failed to repeat the STAP phenomenon, announced her resignation through a statement presented by RIKEN officials this morning.
As quoted in the Asahi Shimbun, a Japanese newspaper, Obokata expressed both consternation and contrition: “I regret that I had to conduct my work (for verification tests) within limitations that were much greater than I had anticipated and therefore was not able to do the examination to the fullest. But, under the given circumstances, I tackled the work to the limit of my soul. Now, I am exhausted. I am extremely perplexed by such a result (of my verification tests).
“Due to my immaturity, I caused difficulties to many people, including those in Riken, concerning the retraction of my articles. I can't apologize enough for that.”
For its part, the RIKEN accepted Obokata’s resignation while indicating that it still intended to pursue disciplinary actions to address the scandal. In addition, the RIKEN said it would discontinue efforts to replicate the STAP results that had been reported by Obokata and colleagues.
STAP promised a surprisingly simple means of producing stem cells—subjecting stem cell precursors to slightly adverse conditions, such as a mild acid bath. The approach generated intense interest and close scrutiny, and soon researchers around the world began finding discrepancies in the STAP articles. Problems included irregularities in the articles' illustrations. Most damaging, however, were reports that STAP resisted attempts at replication.
Starting last July, Obokata attempted to replicate STAP while under close scrutiny. Also, an independent group of scientists at RIKEN pursued their own verification efforts. Summarizing the outcome of these efforts, RIKEN scientist Shinichi Aizawa, as reported by the Japan Times, said, “We were unable to replicate the STAP phenomenon. We’ll end our verification experiments at this point.”