Obokata's work, originally conducted in RIKEN's Center for Developmental Biology (CDB) and published in January 2014 in two separate Nature papers, described a phenomenon known as stimulus-triggered acquisition of pluripotency (STAP) and claimed to reprogramme adult cells into an embryonic stem-cell status using an acid bath.
But soon after the publication of this thought-to-be groundbreaking concept, the data were questioned, triggering controversy. A number of mistakes, including misleading photograph captions and plagiarism, were found in the two publications leading to their retraction after six months (see BioNews 757).
Later, in October 2014, Waseda University started processes to revoke Obokata's doctoral thesis according to their degree guidelines. With the major issue being the plagiarised content and scientific inaccuracies, Obokata was asked to revise her doctoral work within a year, and to retrain in thesis-writing and research ethics.
At the end of this deadline in October 2015, Waseda reported that although they offered adequate help to Obokata for submitting the reviewed thesis, the required level of revision was not achieved. The University president, Professor Kaoru Kamata, announced the finalised decision of the graduate dean's committee to revoke Obakata's PhD.
Obokata criticised the decision as unfair and her lawyer, Mr Hideo Miki, said the University reached this position through social pressure rather than academic reasons.
Earlier, a team of scientists from RIKEN's CDB, using a whole-genome sequencing approach for analysing the samples of the study, found that, in the original studies, the cells had been contaminated with embryonic stem cells.
RIKEN had previously concluded that 'this was an act of research misconduct involving fabrication'. Obokata, without giving up her position that the STAP cells exist, publicly apologised at the time.
An international effort to reproduce the STAP phenomenon, amounting to more than 100 attempts, has been unsuccessful and scientists are now fully convinced that an acid bath cannot reprogramme cells into an embryonic stem-cell fate (see BioNews 831).