BioEd Online

The credibility of work by Woo Suk Hwang, South Korea's high-profile cloning researcher, has again been called into question. News stations across Korea have broadcast allegations from a collaborator that the pioneering work in deriving stem cells tailored to individual patients, published by Science in May 2005, was based on fabricated data.

Hwang, who works at Seoul National University, has not commented on the reports, and Nature has been unable to verify or refute any of the allegations.

The allegations are based on television interviews with Sung Il Roh, a fertility expert at MizMedi Hospital in Seoul, who co-authored a landmark paper with Hwang and his colleagues¹. The paper described the generation of embryonic stem cells that were matched to specific patients - an important step towards using such cells in therapy. On 15 December, Roh told the Munhwa Broadcasting Company and two other television stations that Hwang had told him "there are no cloned embryonic stem cells".

According to Roh, Hwang said he had cloned six cell lines, but that these were lost to a fungal infection and so were not reported upon. As a result, Roh questions whether any of the eleven cell lines reported in the Science paper were real. Two of the lines are said to be frozen and so may be available for investigation.

The general public seems to accept the latest revelations, says Young Mo Koo, a bioethicist at the University of Ulsan: "Everybody is very disappointed." But at present there is no evidence for the claims other than the television and newspaper interviews.

Seoul National University's Wang Jae Lee, who was pegged to lead an investigation into the Science paper at Hwang's request, told the Korean Herald: "Hwang's research team admitted that there were no embryonic stem cells which it claimed [it] had created...Today is the most shameful day for Korea's science community." Nature is trying to reach Hwang and other team members to verify the allegations.

Newspapers have also reported that Hwang has contacted Science and requested that the paper be retracted. As of 11:20 a.m. eastern standard time on 15 December, Science released a statement saying that neither Hwang nor any of the co-authors have requested a retraction.

If the allegations turn out to be true, the impact on the stem-cell science community will be huge. Other evidence of cloned human cells, produced by Hwang's group in 2004, could also be called into question. "We must wonder about the whole lot," says Alan Colman, chief executive at ES Cell International in Singapore.

"The effect on the hopes of the people and the financing of science in the area would be huge. It would leave a stain on all research in this area and lead to a lot of soul searching," says Colman.

Nature is following this story to see if and when any conclusions can be drawn.