The admission on March 14 by the prestigious government-backed Riken research institute that there were “grave errors” in two papers on a possible new method to create pluripotent stem cells is most regrettable.
A group of 14 Japanese and U.S. researchers headed by Dr. Haruko Obokata, at Riken’s Center for Developmental Biology in Kobe, conducted the potentially groundbreaking stem cell research. Since Obokata and two co-authors from Riken are looking into the possibility of retracting the papers after consultation with other co-authors, there is the possibility that the findings themselves will come to naught.
In that case, serious doubt would be cast on the credibility of Riken itself as a science research institute, raising questions such as whether Japanese researchers are faithfully following basic rules in carrying out experiments and writing papers. It is imperative that Riken examine its system of reviewing papers written by its researchers and overhaul it if necessary.
In the papers published in Nature magazine toward the end of January, the 14 researchers said they had soaked lymph corpuscle taken from 7-day-old mice in mildly acidic liquids for about 30 minutes, cultured a few cells that survived, then transplanted them into mice. They said they found that the cells developed into nerve and muscle tissues. They named this new way of reprogramming adult cells into pluripotent cells “stimulus-triggered acquisition of pluripotency,” or STAP.
Since February, questions and suspicions have been raised about the papers, the most serious of them being a claim that STAP cells cannot be produced when the experiment is replicated. As a result, Riken set up an investigative committee to examine six questionable items in the papers.
The committee found “inappropriate handling” of research data in two of the six items but said no malice was involved. Regarding the “unnatural appearance of colored cell parts,” the report said the “process of preparing these images did not constitute fabrication within the context of research misconduct.” It also said that there was no malice found in the resemblance of two supposedly different images of mice placenta, and said that it saw “nothing to contradict the explanation that one of the figures had inadvertently been left undeleted during the process of manuscript creation.”
But even if malice was not involved, it is clear that basic rules for writing a scientific paper were violated.
The committee said the four remaining items require further investigation. The most crucial of these is the close resemblance between photos that appeared in Nature magazine and photos Obokata used in her Ph.D. dissertation submitted to Waseda University in 2011. The former shows that a STAP cell can grow into various cell types while the latter shows differentiation of a cell produced through a method different from the STAP method.
A simple question is why papers with so many problems were produced. Obokata’s relatively young age, 30, cannot be used as an excuse. Riken must carry out a thorough investigation to find out who made mistakes at what stage, then establish a rigorous system to prevent the recurrence of such problems.
Now the researchers involved face the challenge of re-enacting the experiment and producing STAP cells. In addition to this endeavor, Riken must disclose enough information to enable replication of the experiment so that outside researchers can examine whether STAP cells can be really produced.