On August 7, 2026, Gotham City Research LLC published a report titled "Sumitomo Chemical and Sumitomo Pharmaceutical: Part Ⅱ CiRA, Dr Yamanaka, and the undisclosed history of image duplication concerns." We hereby present the position of Professor Shinya Yamanaka, CiRA Foundation, and the Center for iPS Cell Research and Application, Kyoto University (CiRA) regarding its contents.

The current report lists ten papers together as being associated with CiRA or with Professor Yamanaka. However, Professor Yamanaka's role in each paper, the nature of the issue raised, and the status of the subsequent response differ substantially from paper to paper. Below is a summary of the facts.

Of the ten papers, there are three - Nos. 1, 2, and 7 listed in the table of the report - for which Professor Yamanaka bears direct responsibility for the research as either the first author or corresponding author. For Papers 1 and 2, the concerns were investigated and reviewed when they were raised previously, and the necessary actions have already been completed. With regard to Paper 7, Professor Yamanaka reviewed the matter in response to the current report and concluded that the two images alleged to be similar are not identical, and that this does not constitute duplicate use or misidentification of an image.

For Papers 4, 5, 6, 8, and 9, Professor Yamanaka was included as a co-author because he provided research materials, such as iPS cells or knockout mice. For Papers 8 and 9, the corresponding authors have already reviewed the relevant issues and made the necessary corrections. Regarding Papers 4, 5, and 6, upon receiving the current report, the corresponding authors or other relevant authors were contacted and confirmed that they would review the matters and address them appropriately.

For Papers 3 and 10, researchers affiliated with CiRA are authors, but Professor Yamanaka is not an author. Paper 3 was found to involve research misconduct while Professor Yamanaka was serving as Director of CiRA. Following an investigation, the paper was retracted, and disciplinary action was taken against the first author who had fabricated data. As Director of CiRA at the time, Professor Yamanaka took the matter very seriously and implemented measures to help prevent recurrence. Although the current report notes that the details of disciplinary action against Professor Yamanaka were not disclosed, Kyoto University discloses disciplinary actions only when they constitute formal disciplinary sanctions (chōkai) or higher in accordance with its standards, and Professor Yamanaka was not subject to any such action. Regarding Paper 10, Professor Jun Takahashi, the corresponding author, is currently reviewing the concerns raised and proceeding with appropriate action.

Thus, the ten papers listed in the report include matters that were reviewed and resolved in the past, matters that corresponding authors are currently reviewing and addressing, papers on which Professor Yamanaka was a co-author because he provided research materials, and papers on which Professor Yamanaka was not an author at all. Treating these different cases collectively as though they demonstrate an ongoing pattern of research misconduct by Professor Yamanaka or by CiRA disregards the facts specific to each case and is completely unacceptable.

Science advances through criticism and verification. We therefore do not object to specific questions being raised about data or figures in scientific papers. On the contrary, authors should respond to well-founded concerns sincerely and transparently.

At the same time, raising scientific questions must be clearly distinguished from assigning responsibility for research misconduct to an individual researcher without sufficient evidence. It is not a scientifically fair assessment to place resolved cases and ongoing reviews, corresponding authors and co-authors who provided research materials, and even papers on which the individual is not an author side by side without distinction, and then characterize them collectively as a "pattern" of research misconduct. We strongly object to statements that, without sufficient basis, damage a researcher's integrity or reputation.

August 9, 2026
Shinya Yamanaka
Center for iPS Cell Research and Application, Kyoto University
CiRA Foundation