The promising, but ultimately discredited STAP approach is neither robust nor reproducible, and any hint of reported pluripotency was due to contamination, according to two papers appearing in Nature this week.
The method, published in Nature in 2014 in two papers from Haruko Obokata, then at Riken, and colleagues could purportedly transform cells into pluripotent cells by exposing them to a strong stimulus like low pH. But, other scientists quickly uncovered flaws in the papers, which led to their retraction, findings of misconduct, and Obokata's resignation, among other fallout.
But as Nature News notes, where the pluripotent cells in the Riken team's work came from has been unclear.
A team of Boston-based researchers reports this week in Nature that seven labs attempted to replicate the Riken team's work and conducted genetic analyses on the donor and converted cells. From this, the team reports that the approach was neither robust nor reproducible.
Meanwhile, a separate Riken team also reports in Nature on its genome sequencing study of the STAP samples. It reports that the cells that had been thought to STAP-created stem cells were in fact contamination from previously established embryonic stem cell lines.
How this contamination occurred remains an open question, and Nature News notes that multiple instances of contamination would've had to have occurred to explain the errors.
"It is very difficult to reconcile the data with simple contamination or careless mislabeling," says Harvard Medical School's George Daley, one of the authors on the first paper this week examining the STAP approach.
In a related review, Daley and his colleagues also suggest that the scientific community learn from this episode. "Before publication, we encourage that researchers claiming landmark reprogramming advances first demonstrate replication by independent laboratories and incorporate forensic genomic analyses to confirm appropriate cell provenance," they write. "Science is ultimately a self-correcting process where the scientific community plays a crucial and collective role."