TOKYO — A Japanese government-funded laboratory said Friday that it has found “inappropriate handling” of data in a widely heralded stem-cell research paper, but has yet to discover anything that amounts to misconduct.

In an interim report released Friday, the RIKEN research institute said an investigative committee did not find any misconduct in two of the six parts of the paper it is scrutinizing.

RIKEN President Ryoji Noyori, a Nobel laureate in chemistry, said the institute is looking into “significant discrepancies” in the preparation of articles about the research published in January in the journal Nature.

“It may become necessary to demand the withdrawal of the articles,” he told a packed news conference in Tokyo.

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RIKEN and Nature are investigating accusations of duplicated images of DNA fragments and partial plagiarism.

Three authors of the paper have agreed to a retraction, said Masatoshi Takeichi, head of RIKEN’s Center for Developmental Biology, but the decision hinges on a consensus of all the authors and the journal itself. Researchers in Boston and Japan conducted the experiments.

The results were seen as a possible groundbreaking method for growing tissue to treat illnesses such as diabetes and Parkinson’s disease using a simple lab procedure.

The institute emphasized that the aim of the investigation is solely to determine whether there was any misconduct, and not the veracity of the research itself. Takeichi said verification of the results depends on their reproduction by independent researchers.

The articles described a surprisingly simple method of transforming mature cells into pluripotent stem cells capable of regenerating any type of tissue in the body. The key was to stress them by soaking them in an acid bath for 30 minutes, prompting genetic changes that made the cells more flexible. The researchers dubbed their technique “stimulus triggered acquisition of pluripotency,” or STAP.

Using the technique, the researchers claimed to have fundamentally transformed mouse cells by exposing them to acid.

Concerns about the Nature articles were raised soon after their publication on the blog PubPeer, while the Knoepfler Lab Stem Cell Blog invited researchers to report on their efforts to reproduce the study’s results.

Material from the Los Angeles Times is included in this report.