Results of an attempt to reproduce the STAP phenomenon

This reports the results of an attempt by Haruko Obokata to replicate the phenomenon of stimulus-triggered acquisition of pluripotency (STAP), which was first reported in a pair of papers authored by Obokata and colleagues in 2014. The most conclusive evidence for the pluripotency of so-called STAP cells was their purported ability to contribute to chimera formation. In the follow-up trial presented here, putative STAP cells prepared by Obokata were injected into 1154 embryos, of which 671 were recovered. However, the injected cells made no significant contribution in any tissue in any of the embryos developed.