A South Korean scientist who claimed to have cloned the first human embryonic stem cell is now requesting that some of his published work be retracted. But as Science News went to press, it was still unclear whether the abrupt turnaround arose from scientific fraud, a laboratory mistake, or both.
Either way, the fiasco is a setback for stem cell research, other scientists say.
In the March 12, 2004 Science, Woo Suk Hwang of Seoul National University and his team reported that they had removed DNA from a human egg, replaced it with DNA from a mature cell, and then grown the altered egg into a cluster of cells. It appeared that the researchers had thus cloned human stem cells, with the potential to develop into any cell in the body (SN: 2/14/04, p. 99: Tailoring Therapies: Cloned human embryo provides stem cells).
In May 2005, the team reported an improved process with large potential benefits (SN: 5/21/05, p. 323: Perfect Match: Embryonic stem cells carry patients’ DNA). The researchers created 11 distinct stem cell lines tailor-made to individuals. The result appeared to pave the way for customized replacement tissues.
The 2005 work, published in the June 17 Science, has now been called into question. Hwang and one of his U.S. coauthors, Gerald P. Schatten of the University of Pittsburgh, last week asked Science to retract that paper. Hwang says that there were mistakes in the 2005 report, but he hasn’t specified what they are. He acknowledged that some of the stem cell lines were contaminated with yeast cells.
However, study coauthor Roh Sung Il of MizMedi Hospital in Seoul claimed in the Korean media that Hwang had told him that some of the stem cell lines described in the paper had been replaced by fakes.
The University of Pittsburgh and Seoul National University have begun investigating the cloning research.
In a press conference in Korea, Hwang denied fabricating data but said that some of the stem cells reported as cloned might have been intentionally switched with conventional stem cells. He says that he is asking police to investigate.
“I think this is a shame,” says Leonard I. Zon, a stem cell researcher at Harvard Medical School in Boston. The controversy won’t be cleared up until other researchers replicate the work, he says. Meanwhile, Zon says that he hopes that stem cell research will proceed.
Hwang said at the press conference that he has frozen stem cells that he can use to demonstrate that his cloning procedure works.