It's a pillar of the scientific method: Fraud or errors in a scientific finding from one lab are exposed when other labs can't confirm the work. But that process has been hobbled in the stem-cell research scandal in South Korea, some scientists say. The reasons include the technical challenges of the work and restrictions by the U.S. government.
Researcher Hwang Woo-suk of Seoul National University resigned his post Friday after investigators concluded he had faked results in a headline-grabbing report published in May.
The original study said Hwang's lab had created 11 lines of embryonic stem cells genetically matched to individual patients. The investigators concluded that at least nine of those lines were bogus.
The fraud findings cast doubt on Hwang's other work, including his claim in February 2004 to have been the first to clone human embryos and extract stem cells from them.
Nobody has yet published a success in duplicating or extending that experiment. Scientists say such follow-up work is key to rooting out errors and falsehoods in scientific findings. If nobody can duplicate or extend the results of an experiment, then questions about the original findings arise.
But the failure to confirm the 2004 Hwang research doesn't necessarily mean it was bogus, cautions Dr. Curt Civin of Johns Hopkins University Medical School, editor of the journal Stem Cells. He pointed to several obstacles to trying to do such followup work.
Such attemps are off-limits in many U.S. labs because the government restricts federal money for human embryonic stem cell experiments, he said. Labs that depend on federal money cannot use it to create new embryonic cell lines as Hwang claims he did.
The federal policy dampens the possibilities for followup work in other countries because "a lot of countries look to us for guidelines on what they should do," Civin said.
What's more, few labs are prepared technically to do such work.
"If it were something that was important and could be done by many labs, and was not prohibited," he said, many scientists would have attempted it by now.
John Gearhart, also a Hopkins researcher, said another impediment is that Hwang's lab has not shared enough details of its technology to allow other labs to duplicate it. And apart from technical acumen, few labs in the world have permission to do work that would build on the Korean report.
Maybe some labs have tried and failed but kept quiet about it, Civin said, because the scientists "didn't feel like saying they weren't as good as the South Koreans."
Indeed, the technical expertise of Hwang's lab has often been mentioned as a crucial ingredient in its reported success. Hwang has attributed his lab workers' dexterity to lots of practice with steel chopsticks, the USA Today reports.
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