A South Korean scientist said today he had proof his team had made patient-tailored stem cells this year but that the cells had later been badly contaminated.
Hwang Woo-suk, whose work is under intense scrutiny, told a televised news conference at Seoul National University five frozen stem cells were in the process of being thawed for analysis. He expected results in 10 days.
Hwang's team published a study on tailor-made human stem cells in May in the journal Science.
Seoul National University said it would step up an investigation into Mr Hwang, the country's top stem-cell scientist, after reports a day earlier that key parts of the paper had been fabricated.