This week, Nature revisits one of the most controversial scientific episodes in recent years: the now-retracted discovery of a claimed new way to reprogram cells, stimulus-triggered acquisition of pluripotency (STAP). On our website we publish two Brief Communications Arising (BCAs) that relate to the retraction. And on page 469 we publish a related Review on pluripotency.

One BCA details the efforts made by many laboratories to reproduce the STAP phenomenon without success (A. De Los Angeleset al.Nature;2015). The other presents the results of a genomic analysis of the claimed STAP cells, performed as part of a 2014 investigation by Japan’s RIKEN institute but not previously published (D. Konnoetal.Nature;2015). Using sequencing-based approaches, this analysis shows that all of the claimed STAP cell lines were contaminated with embryonic stem cells, and that this contamination affected the results. De Los Angeles and colleagues’ BCA also includes an analysis of sequencing results published in the original papers, and reaches similar conclusions regarding contamination.

The Review, written by a collaboration of leading scientists who work with pluripotent stem cells, offers a state-of-the-art summary of the field, and provides a checklist that researchers can use to determine whether a cell has pluripotent capacity.

Why is Nature publishing these pieces? The main reason is to update the scientific record. The wording of the STAP retraction notices left open the possibility that the phenomenon was genuine. It said: “Multiple errors impair the credibility of the study as a whole and we are unable to say without doubt whether the STAP-SC phenomenon is real.” The two BCAs clearly establish that it is not.

It is also important to recognize and highlight the community-driven effort to reproduce the findings. The negative results of some of these efforts were made public informally during the controversy, but for some lengthy experiments this was not possible. Science-in-the-making can be made public immediately. But, ultimately, reproducibility efforts should be peer reviewed.

Another reason why Nature has chosen to publish this trio of pieces is to address some of the indirect questions posed by the high-profile controversy, which provoked discussions in both the stem-cell field and the broader research community. The Review, in particular, is intended to offer guidance from the community to help researchers, editors and reviewers to decide how best to evaluate future claims as well as how to view those already published in the scientific literature. Comparing the genotypes of reprogrammed pluripotent stem cells with those of parental cells, it points out, can check their provenance.

The stem-cell field holds enormous promise for therapy. As a result, all claims of considerable importance should be verified with utmost care before being made public. The Review suggests that such claims in the field of reprogramming and pluripotency should be demonstrated in more than one experimental model, and encourages their independent replication.

Nature will endeavour to help the field to achieve its promise, and is looking at ways to support and encourage this reproducibility enterprise. For example, we ask authors to include more details about the methods developed in their studies. We strongly encourage our authors to deposit step-by-step protocols on freely accessible platforms, such as Protocol Exchange ( — this may be requested for extraordinary claims, at the editor’s discretion. We encourage our authors to verify the origin of the cell lines they use, as we do for cancer cell lines (see Nature 520, 264; 2015).

The Review concludes: “Science is ultimately a self-correcting process where the scientific community plays a crucial and collective role.” In this case, the stem-cell community has excelled in that role and should be congratulated.