Dr Hwang and the stem cell swindle

It is not often that a country issues a commemorative stamp in honour of a living scientist. But, in South Korea, Hwang Woo-suk became an instant national hero when he claimed to have grown stem cells from the world's first cloned human embryos.

The 220-won stamp in question depicted a nucleus being extracted from a human egg cell, placed alongside a paraplegic in a wheelchair who, in a series of Darwinian-like stages, rises tentatively to his feet before leaping and embracing a loved one.

Dr Hwang's breakthrough – creating human embryonic stem cells – offered to be the saviour of anyone with multiple sclerosis, Parkinson's disease, motor neurone disease, and a host of other devastating illnesses.

But soon after the stamp was issued in February 2005, Dr Hwang's brilliant career began to unravel. The story of his downfall ended in a South Korean court yesterday, where he was convicted of embezzling research funds, illegally buying human eggs, and of other serious charges related to his fraudulent research.

Dr Hwang, 56, was spared a custodial sentence by Judge Bae Ki-yeol of Seoul Central District Court although prosecutors had asked for four years in prison. Judge Bae said he had shown remorse and gave him a suspended sentence. But for the former scientific superstar of Seoul National University, the court's ruling was the final disgrace in a career that had taken him, in three years, from relative obscurity to international pariah via a brief interlude of global fame.

Dr Hwang burst on to the international scientific stage five years ago with a study claiming to have generated the world's first cloned human embryos by fusing human skin cells with unfertilised human eggs that had had their nucleus removed. It was the same technique that created Dolly, the famous cloned sheep.

A year later he published a second study, claiming to have generated 11 different "lines" of embryonic stem cells tailored from the skin cells of 11 people of various ages, sexes and stages of health. These embryonic stem cells were supposedly proof that patients could supply their own regenerative tissue for transplants without fear of rejection.

Both studies, which were published in the top scientific journal Science, have now been retracted after some of the results were shown to be fabricated. Dr Hwang was also found to have engaged in scientific misconduct after it emerged he had lied about taking eggs from his own junior researchers – a serious breach of medical ethics.

But despite having both studies thrown out in their entirety, Dr Hwang made some important contributions to science. It is now clear, for instance, that he was the first person to clone a dog, an Afghan hound named Snuppy – a breakthrough other cloning scientists have hailed as an important achievement.

It is also clear that whatever Dr Hwang did or did not do in the two retracted studies, he at least got to a stage of embryonic development that other researchers have found difficult to emulate.

He also managed to produce stem cells from a human egg that underwent spontaneous development in a process known as parthenogenesis – "virgin birth" – even though he had mistakenly claimed it was via cloning.

His downfall began when doubts were raised over the source of the human eggs he had used. He claimed they came from volunteers who had not been paid for their efforts, apart from expenses. He also said he used 427 human eggs in his cloning research, but it later emerged he had access to more than 2,200 – including those taken unethically from his female colleagues.

In press conferences in Britain and the US, he evaded questions by journalists about the source of his eggs, hiding behind his inadequate English. However, the issue emerged in public for the first time in a report in the journal Nature in May 2004, when one female student working in his lab admitted she had donated eggs, only to retract the admission later on.

In December 2005, an investigative TV programme in South Korea repeated similar accusations, and the "nagging questions" about Dr Hwang's egg supply exploded into the public domain. He finally admitted members of his team had donated eggs, but said he had only lied about it to protect their privacy.

Politicians and the public in South Korea came to his defence. The president, Roh Moo-Hyun, attacked the television station, the Munhwa Broadcasting Corporation, which was forced to apologise. The programme, PD Notebook, was taken off air.

However, photographs used in one of Dr Hwang's studies were later found to be duplicated from another study, and questions were raised about critical DNA fingerprints which purported to show the cloning had worked. Crucially, one of his American colleagues, Professor Gerald Schatten of Pittsburgh University, who had been one of his staunchest supporters and a joint "corresponding author" of the 2005 study, wrote to Science voicing his own concerns. Within weeks Dr Hwang was found by his own university to have fabricated data.

The shock waves of his downfall were felt around the world. Many of the most skilled cloning experts were left wondering whether they had wasted their efforts – and research funds – on trying to replicate Dr Hwang's work.

The journal Science has since launched its own investigation on what can be done in the future to prevent, or at least limit the damage of, deliberately fraudulent research.

Dr Hwang's name was once synonymous with scientific success and probity. He has now become a busted flush.

Stem cells: A medical revolution

*Embryonic stem cells have the potential to develop into any one of the scores of specialised tissues of the body, from heart muscle to brain cells.

*Scientists would like to make stem cells from cloned human embryos derived from skin cells, which would overcome problems of tissue rejection.

*Newcastle University has also produced cloned human embryos but has not been able to extract "lines" of stem cells for medical use.

*An alternative to embryonic cloning, called iPS, is seen as potentially more useful than relying on a supply of human eggs.