In a scandal that rocked Japan's scientific establishment, Riken -- the research institute that sponsored the study -- launched an independent experiment in April to verify research published by scientist Haruko Obokata and her colleagues earlier this year.
But the failure to replicate the experiment casts further doubt on the existence of stem cell-like cells, what the researchers called Stimulus-Triggered Acquisition of Pluripotency (STAP) cells.
"Researchers have conducted 22 experiments thus far, but we could not confirm the emergence of cells in the conditions described in (Obokata's) papers," Riken said in an interim report issued today.
The researchers will continue their experiments under more diverse conditions while also considering data obtained by Obokata herself, Shinichi Aizawa, a special adviser at Riken, told a lengthy press conference.
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Obokata was feted after unveiling findings that appeared to show a straightforward way to re-programme adult cells to become stem cells -- precursors that are capable of developing into any other cell in the human body.
Identifying a readily manufacturable supply of stem cells could one day help meet a need for transplant tissues, or even whole organs, meaning that any advance in the field is met with excitement in the scientific community.
Leading science journal Nature withdrew the flawed stem-cell study after Obokata agreed in June to retract the papers.
Nature said it would tighten procedures to vet future studies submitted for publication.
It said the decision was taken after mistakes were discovered in some data published in two papers, photograph captions were found to be misleading, and the work itself could not be repeated by other scientists.
Earlier this month Obokata's co-author, stemcell scientist Yoshiki Sasai, hanged himself, further shaking Japan's scientific establishment.