Stem Cell Researcher Defends His Work

SEOUL, South Korea, Dec. 16, 2005 — -- Stem cell researcher Hwang Woo Suk denied allegations made by his close colleague that he faked results in a paper published in the journal Science, but admitted that there was "irretrievable human error" in the process.

The colleague, Dr. Roh Sung Il, an executive at MizMedi Hospital in Seoul, surprised scientists worldwide by announcing Thursday that Hwang had told him nine or even possibly all of the 11 patient-specific embryonic stem cells reported in the Science article earlier this year did not exist.

Hwang defended his work at a news conference on Friday, saying he could prove the existence if given more time. He also struck back by raising concerns that "someone might have switched the original stem cells to a fake one from Roh's laboratory."

Immediately after Hwang's nationally televised live news conference, Roh emotionally rebutted Hwang's suspicions, saying he would not be a "sacrificial lamb" while Hwang tried to escape from the crisis.

Hwang's research has been the center of global controversy because it involves humanly created and destroyable human embryos. In theory, if the technology becomes viable, biological "replacement parts" of a patient donor could be generated, which has been the ultimate hope for patients with rare neurological diseases and spinal cord injuries.

Prior to this and other allegations, Hwang was revered by scientists for his recent work that uses a cloning method called somatic-cell nuclear transfer to create lines of genetically identical stem cells.

Hwang's Seoul National University lab and Roh's MizMedi Hospital worked closely together on the project. Hwang was in charge of the nuclear transfer and Roh in charge of collecting eggs for nuclear injection in the primary stage and later generating stem cells from the nucleus.

In the midst of the blame game between the two sides, both agreed to retract the article from Science after agreement from the rest of the coauthors. The journal's editorial staff released a statement Friday morning saying they had been contacted by Hwang and his former colleague, University of Pittsburgh biomedical researcher Gerald Schatten, about a retraction, but that they would only honor the request if all 25 authors agreed to have their names removed.

Hwang says his request to withdrawal was not because he faked the stem cells, but because his 11-page study was tarnished by mistakes made in taking photographs and in the preservation of stem cells.

Among the series of suspicions questioning the validity of Hwang's research: South Korean scientists' concluding that some photos of the 11 stem cell colonies in the May article depicted the same group of cells.

Kim Sun-Jong, a junior researcher, told the South Korean broadcast network MBC that he was "told (by Hwang) to make pictures of 11 cells out of two" to make it appear "that there were more than there really were."

Hwang, however, said that he merely asked Kim to "take many photographs and allocate the best ones" for submission to Science, not to fabricate them.

Supporters of Hwang are holding out hope since Kim confirmed to a television network Friday that he believed the embryonic stem cells existed because he and seven other researchers cultured and successfully harvested eight stem cells, and three more were in the process.

Hwang believes that "someone with some purpose" may have switched his original patient-specific embryonic stem cells with fake ones, in the process of trying to recover from a fungus contamination at his laboratory, which damaged all six cells the team had at that time.

Hwang's team had delivered the damaged cells to Roh's MizMedi lab, which failed to recover them, but had two new different cells in storage. Hwang's team continued to culture those cells while creating the additional nine, but "recently we found that that some of these stem cells were not ours," he said.

Hwang, on Friday, requested an official investigation to clarify whether his cells were tampered with or replaced.

In spite of these allegations, Hwang pleaded that he would prove the existence of the original stem cells, announcing that he had already begun to defrost five stem cells that had been in storage.

These cells would be ready for a DNA authenticity test in about 10 days.

Hwang also suggested that he could replay the whole process as he kept the research diary and microfilms of the original research. But if none of the defrosted cells proved to be authentic, Hwang said he would be confident that the cells were purposely switched in the process.

"If all of those five cells turn out to be MizMedi's, I can only translate that my cells were all switched in the first stage," he said.

Roh also told reporters that MizMedi Hospital would conduct its own investigation with two remaining and frozen stem cells.