In the early 2000s,
Charles Vacanti and Martin Vacanti conducted studies that led them to the idea that stem cells—
spore-like cells—could be spontaneously recovered from ordinary tissues that are stressed via mechanical injury or increased acidity. The technique for producing STAP cells was subsequently studied by Obokata at the
Brigham and Women's Hospital (BWH), while she was studying as a post doc under Charles Vacanti, and then at the
RIKEN Center for Developmental Biology in
Japan. In 2008, while working at
Harvard Medical School, she verified at the request of Charles Vacanti that some of the cultured cells she was working with shrank to the size of stem cells after being mechanically injured in a
capillary tube. A series of experiments, first turning a mouse embryo green by fluorescently tagging STAP cells, then videotaping the transformation of T-cells into pluripotent cells, finally convinced skeptics that the results were real. To address the problem of reproducibility in other laboratories, Obokata published some technical 'tips' on the protocols on March 5 while promising that the detailed procedure would be published in due course. On March 11, Teruhiko Wakayama, one of Obokata's coauthors, urged all the researchers involved to withdraw the articles, citing many "questionable points". Charles Vacanti said he opposed their retraction and posted a "revised protocol" for creating STAP cells on his own website, which was taken down after he resigned his BWH post. On March 14, RIKEN released an interim report of the investigation. Out of the six items being investigated, the committee concluded that there was inappropriate handling of data on two items, but did not judge the mishandling as research misconduct. On April 1, RIKEN concluded that Obokata had engaged in "research misconduct", falsifying data on two occasions. The co-authors were cleared of misconduct, but bore "grave responsibility" for not verifying the data themselves. RIKEN also announced that an internal group had been established to verify whether the ‘stimulus-triggered acquisition of pluripotency’ is reproducible. Obokata maintained her innocence and said she would appeal the decision. In the wake of the controversy, observers, journalists, and former members of RIKEN have stated that the organization is riddled with unprofessional and inadequate scientific rigor and consistency, and that this is reflective of serious issues with scientific research in Japan in general. RIKEN commissioned a team of scientists to attempt to verify Obokata's original results and asked Obokata to participate in the effort. On August 5, 2014, Obokata's supervisor and co-author of the original paper,
Yoshiki Sasai, was discovered dead by apparent suicide by hanging in a building at the RIKEN facility in Kobe, Japan. On September 24, 2015, the RIKEN scientists reported that Obokata's STAP cells came from embryonic stem cell contamination, while on the same day, research groups who had attempted to reproduce the STAP protocol jointly reported that they had found it irreproducible. ==Implications==