RIKEN STAP cell fraud — two Nature papers retracted, supervisor dead by suicide

In January 2014, the scientific world was electrified by a discovery from Haruko Obokata, a young researcher at Japan's RIKEN Center for Developmental Biology. She claimed that subjecting ordinary cells to stress — a weak acid bath, bacterial toxins, or physical trauma — could transform them into pluripotent stem cells, capable of becoming any tissue in the body. The method was called STAP (Stimulus-Triggered Acquisition of Pluripotency). If real, it would have been radically simpler than existing stem cell techniques, and the results were published in two papers in Nature.

The excitement lasted weeks. Scientists around the world tried to replicate the results and failed. By February, RIKEN had launched an investigation into allegations of image duplication and data irregularities. By April, the investigation concluded that Obokata had falsified data on two occasions — she had manipulated gel images and used data from different experiments as if they were from the same one. Her laboratory notes were so poor that the experiments could not be traced. In June, Obokata agreed to retract both papers. The retraction was published in Nature on July 2, 2014.

The scandal devastated RIKEN. Yoshiki Sasai, Obokata's supervisor and a respected stem-cell biologist, was cleared of misconduct but criticized for inadequate supervision. On August 5, 2014, he was found dead by apparent suicide at a RIKEN facility in Kobe. He had described himself as overwhelmed with shame. Obokata maintained her innocence, but her PhD was later revoked by Waseda University for plagiarism. The scandal was seen as reflecting broader problems with research oversight in Japanese science.