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Embattled Stem Cell Researcher Apologizes but Defends Her Work

"STAP cells exist!" said Obokata, shown here during a January press conference, today in Osaka.

On the defense. "STAP cells exist!" said Obokata, shown here during a January press conference, today in Osaka.


TOKYO—In her first appearance before the press since her claims of an astounding breakthrough in stem cell research started unraveling, Haruko Obokata, of the RIKEN Center for Developmental Biology in Kobe, Japan, apologized for the trouble she has caused her employer, her colleagues, and the scientific community. But she also firmly maintained that STAP cells, the new type of stem cells she claims to have developed, exist, and said she will not retract the two Nature papers reporting her finding.

“I sincerely apologize to RIKEN, my co-authors, and to many others for the trouble I caused through my insufficient experience and carelessness," Obokata said with a deep bow at the beginning of the press conference, which was held in Osaka. But "STAP cells exist!" she defiantly declared in response to a question. She also pledged to "go anywhere" to help any interested scientist reproduce her results.

Obokata last faced the press when she and colleagues at RIKEN and other institutions in Japan and at Harvard Medical School in Boston published a research article and a letter online in Nature on 29 January. The 30-year-old was lionized in Japan for her unexpected breakthrough, a method to create stem cells that she called "stimulus-triggered acquisition of pluripotency," or STAP. It works by subjecting mature cells to a brief acid bath and then tweaking culture conditions. But soon there were reports of doctored images and plagiarism, and to date, no one has reported replicating the first step in creating STAP cells. One co-author has called for the papers to be retracted.

A RIKEN investigating committee announced on 1 April that it had found two instances of research misconduct. RIKEN President Ryoji Noyori said at the time that Obokata would be given a chance to appeal before a disciplinary committee would be convened. Obokata's lawyers filed the appeal with RIKEN yesterday.

At the press conference, Kazuhiko Murotani, one of her attorneys, elaborated on Obokata’s previous claims that there was no intent to deceive, and that the problems in the papers do not affect the results. He did reveal a few new details. For instance, Obokata had previously admitted to using images from her doctoral thesis in the Nature papers by mistake; Murotani explained today that the images did not come directly from the thesis, but rather resulted from a mix-up of PowerPoint slides.

He also parsed the meaning of the term "fabrication," claiming it describes cases where an image is made up completely from scratch and intended to deceive. That’s not what happened in Obokata’s case, where images were inadvertently mixed up, he said. He said the investigating committee had rushed to a conclusion without giving Obokata sufficient opportunity to present her side of the story. Obokata, through her lawyers, is asking RIKEN to reinvestigate the matter and reconsider the judgment.

RIKEN released a statement confirming receipt of the appeal and saying the institute "will give due consideration to the appeal in accordance with our regulations."

Obokata answered most of the questions herself during a Q&A session that stretched the press conference to a bit over 2.5 hours. Among other things, she said that she has at least four or five lab notebooks containing the details of her experiments, not the two notebooks the investigating committee mentioned in its report; unfortunately, they are scattered among the various labs she has worked in.

She apologized several times for the errors in the papers, but also repeatedly expressed her faith in her findings. She claimed she has created STAP cells more than 200 times; retracting the Nature papers would indicate that the STAP phenomenon is not real, she added. "If I can continue in research, I want to work to realize the hopes of STAP cells as quickly as possible," she said.

In a related development, at a press conference on Monday, Hitoshi Niwa, a RIKEN senior scientist and a co-author of the papers, outlined how a RIKEN team will try to replicate every step of the experiments reported in the two papers, from the stressing of the cells and the creation of STAP stem cells to testing their pluripotency. He said he expects the effort to take a full year but promised to release interim reports on progress.