A claim of an astoundingly easy way to make pluripotent stem cells reported online in two  papers  in Nature on 29 January continues to unravel as one of the co-authors called for a temporary retraction of the papers while their data and images are verified.
The research coming under fire reported the discovery of a potentially revolutionary process called stimulus-triggered acquisition of pluripotency (STAP), in which exposing adult cells to a stress such as acid or pressure prompts them to behave like cells in early embryos , which can become any cell type in the body. But within days of the work being published, critics on the PubPeer website and other blogs pointed out problems with some of the images in the papers , including some that were very similar to those in earlier papers by first author Haruko Obokata, a unit leader at the Kobe, Japan-based RIKEN Center for Developmental Biology.
RIKEN launched an investigation into the matter on 13 February. Over the weekend, the story took another turn when critics noted that other images in the paper are very similar  to those published in Obokata’s doctoral thesis  in 2011.
And as both The Wall Street Journal  and NHK, Japan's national public broadcaster, reported today, Teruhiko Wakayama of the University of Yamanashi, Kofu, a cloning researcher and co-author of both papers, now says he has lost confidence in the papers. But he is not yet entirely dismissing them.
"Overall, there are too many issues that have become unclear,” Wakayama said in the broadcast news segment . Wakayama continues: “To some extent, confidence in the paper has disappeared. To check the legitimacy of the paper, I think it would be best to temporarily retract it, then prepare accurate data, photos, etc., and then once again, if appropriate, release the paper with confidence."
Wakayama also said that the results of RIKEN's investigation should be open so as to clarify what may have gone wrong. NHK reported that RIKEN had declined to comment.
Scientists around the world have tried to replicate the technique , but to date no one has publicly said they’ve succeeded. On 5 March, RIKEN released more detailed procedures  for the creation of the STAP cells.
Stem cell researcher Paul Knoepfler has closely followed the story on his blog , including posting scientists’ reports  of their attempts to replicate the work. In his most recent online poll, 53% of respondents indicated that they were “convinced” or “close to convinced that [STAP cells] are not real.” In an interview that Knoepfler posted  on 27 February, Wakayama asked that people “wait at least one year” to see if the technique could be replicated.