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South Korean Scientist Denies Faking Stem Cell Data
He said the Hwang-Schatten paper had not been rushed into print but had in fact been analyzed in detail because its findings marked a major first.
"Obviously . . . a paper that apparently achieves a result that others have tried to get and failed gets subjected to especially careful scrutiny, and I think our peer reviewers gave it that," Kennedy said in a conference call with reporters.
The allegations of fraud relate to some of the most notable biomedical research findings of the past several years, in which Hwang described his team's successful derivation of prized embryonic stem cells from cloned human embryos.
Stem cells, which grow inside days-old embryos, have the capacity to morph into virtually every kind of cell in the body and hold promise as all-purpose replacement parts for patients ailing from any number of diseases. Although many teams around the world have isolated stem cells from conventional human embryos created through the fusion of sperm and egg, no one had done so with cloned human embryos.
Cloned embryos, made by the fusion of a person's skin cell and a donated egg whose own DNA has been removed, are genetically identical to the person who donated the initial skin cell. Scientists suspect that since stem cells derived from such embryos would be genetically matched to the person -- presumably a patient who could benefit from a stem cell transplant -- they would be less likely to be rejected by that person's immune system.
No evidence has been presented to call into question those basic findings, described in a 2004 Science article that launched Hwang to global prominence and made him a folk hero in Korea. Nor has anyone raised substantive doubts about another of Hwang's historic achievements -- the first cloning of an adult dog, reported this summer.
The current storm involves a report published in May that claimed the creation of 11 new stem cell cultures, or lines, from cloned embryos with success rates much higher than in the 2004 report -- an improvement in efficiency crucial to the approach becoming medically practical. Among the potential problems are photographs purporting to show different cell lines that instead appear to be copies of a single photo, and mechanical tracings that appear to have been altered or hand drawn.
Earlier this week, Roh claimed that Hwang ordered underlings to fake the photographic evidence and other data. He also claims that most or all of the 11 cell lines do not exist. Hwang has already conceded that some photos were mistakenly substituted for others, but he has repeatedly denied any effort to overstate his accomplishments.
Yesterday, Hwang said that some but not all of his cell lines had succumbed to a fungus infection. He suggested that Roh or another co-worker who had been trying to salvage the dying cells may have secretly swapped other, conventional stem cell lines for the cloned ones after the cloned ones died.
"I am suspecting that my [personalized] cells may have been replaced by MizMedi's cells," Hwang said. "I am truly concerned as to who did such a thing like this for what purpose."
Roh called his own televised news conference after Hwang's, in which he called Hwang a "liar" looking for a scapegoat. Hwang "tries to beat truth with hypocrisy and cheap tricks," Roh was quoted as saying in the International Herald Tribune. "Dr. Hwang is a narrow-minded man who doesn't have the courage to admit that his paper was made with fabrication."
Pittsburgh's Schatten, who first raised alarms about Hwang by abruptly and publicly breaking off their 20-month collaboration in November, continued his weeks-long silence on the matter yesterday.
On Monday, Schatten asked Science to retract his name from the paper, which had listed him as a senior author. Science responded that he could not disassociate himself from the group effort.
"It's a 'sauce for the goose, sauce for the gander' proposition," Kennedy said yesterday. "You have to take the fall if it's wrong."
Special correspondent Joohee Cho in Seoul contributed to this report.