HARUKO OBOKATAStimulus-triggered acquisition of pluripotency (STAP) cells “are likely to have been obtained by combining two kinds of different cells,” The Japan Times reported today (June 4), neither of which were those lead author Haruko Obokata and her colleagues claimed to have used in two January Nature papers, according to RIKEN’s Takaho Endo. Performing an independent analysis of the STAP studies, Endo found evidence to suggest that the cells Obokata’s team created were not from an F1 mouse, but perhaps instead were from B6 and CD1 mice. He even suggested that the mix-up was intentional. “It is quite unlikely that this happens as a result of an accident or mistake,” Endo told reporters.
Meanwhile, Obakata—who was previously found by her institution to be guilty of research misconduct and last month (May 28) green-lighted the retraction of one of the two STAP papers—has agreed to retract the second publication, according to the Japan Daily Press. “She has agreed to retract both articles,” a RIKEN spokesperson told reporters.
Citing unnamed sources, The Asahi Shimbun reported that coauthor Charles Vacanti from Harvard Medical School and Brigham & Women’s Hospital “has also contacted the co-authors and expressed his intention to withdraw the article.”
For its part, Nature has said that it typically tries to get all authors to agree on a retraction before issuing one.
Update (June 4): A spokesperson for Nature said that “the authors are now in discussion with Nature with regard to retraction of both papers,” the Nature News blog reported. “Nature does not discuss retractions until final decisions are made.”