Scientists fretted Friday that a spectacular cloning fraud that hid in plain sight has set back legitimate stem cell work around the world.
Cloning experts and stem cell scientists said research in the potentially revolutionary field of regenerative medicine will continue unabated. But they said public confidence in their work had been weakened by a sham branded by experts as the most visible case of scientific fraud they could recall.
Scientists also struggled to explain how they didn't earlier catch the charismatic South Korean veterinarian's claim in a Science paper published in May that he cloned 11 human embryos to produce stem cells.
"That's a difficult one," said Keith Campbell, the University of Nottingham researcher who helped clone Dolly the sheep in 1997. "Scientists are asked to referee a lot of papers and to a certain extent we have to believe each other as to the validity of the data."
A disgraced Hwang Woo-suk resigned from Seoul National University on Friday after the school said the researcher fabricated groundbreaking cloning and stem-cell research that had raised hopes of new cures for hard-to-treat diseases.
When Hwang published findings in February 2004 and again in May, it was believed he had developed a new cloning method that enabled him to accomplish something no one else had.
Hwang chalked up much of the success to South Korean government support and dedicated researchers working around the clock. He also credited his workers' dexterity with chopsticks; stem cell researchers visited from around the world and rushed back to their labs to try the new technique.
The journal Science said it would retract the May paper and investigate Hwang's 2004 paper that claimed the first cloned human embryo.
'Stain on the whole field'
"It's a stain on the honor and integrity of the whole field," said Dr. Robert Lanza, a cloning expert at the biotechnology company Advanced Cell Technology. "It has sent a lot of scientists on a wild goose chase and down false paths."
Stem cells are created in the first days after conception and mature into every cell in the human body. Scientist hope to use stem cells as replacement parts for failing organs and to treat diabetes, Parkinson's and other diseases.
Researchers want to harvest stem cells by cloning the DNA of sick people, so they could turn the cells into tissue that genetically matches a patient. That way, the patient wouldn't have to take the anti-rejection drugs used in organ transplants today. Also, researchers hope to use cloned stem cells to study how diseases begin and develop.
No researcher in the United States is known to be actively trying to a clone a human embryo, though two teams at Harvard University have asked school officials for permission.
Doug Melton, who leads one of the Harvard cloning projects, vowed Friday that the work will continue despite the scandal.
"This sad news from Korea in no way weakens our belief in all the demonstrably valid experiments indicating that stem cell science holds the promise of eventually providing the basis of treatments and cures for numerous presently intractable chronic diseases," Melton said in an e-mail. "It simply means that we still need to take important steps we thought had already been taken."
Not biggest fraud, but perhaps most visible
Two experts in scientific misconduct called the Hwang scandal the most visible case of scientific fraud they could think of.
That's because unlike many other cases, Hwang's purported achievement drew so much public attention in the first place, said Nicholas Steneck of the University of Michigan.
"His research was front-page research, and then it was discovered that he falsified. Most of the other ones, it's that they falsified that made it front-page research," he said.
The controversy over embryonic stem cells made Hwang's claims so newsworthy, said Fred Grinnell, founder of the ethics in science and medicine program at the University of Texas Southwestern Medical Center in Dallas.
"This is a case where lots of people have been talking about stem cells and embryos and whether it's right to do it or not to do it, and how the U.S. is falling behind, and how there's great work going on in Korea. And all of a sudden it appears to be all fake," Grinnell said.
Both men said other fraud cases have been more extensive.
Grinnell cited the case of Eric Poehlman, once a professor at the University of Vermont College of Medicine, who made up research between 1992 and 2000 in areas including menopause, aging and hormone supplements to get millions of dollars in federal grant money.
"To me, that's the worst case of this kind that I've ever heard of" because he got away with it for so long, Grinnell said.
Similarly, Steneck noted the case of Jan Hendrik Schon, who had become a star at Bell Labs but then was fired in 2002 for falsifying data from electronics experiments. An investigatory committee concluded that he made up or altered data at least 16 times between 1998 and 2001.
In contrast, Steneck said, only one paper by Hwang has been shown to be fraudulent, at least so far.