A 14-year-old paper has earned an expression of concern after an anonymous whistleblower found evidence of image duplication in the work.
The authors have had images from several more papers flagged on PubPeer. The corresponding author, Kelly McMasters, is chair of the Hiram C. Polk, Jr., MD Department of Surgery at the University of Louisville School of Medicine in Kentucky.
The 2010 paper, “Adenovirus-mediated expression of truncated E2F-1 suppresses tumor growth in vitro and in vivo,” appeared in Cancer. It has been cited 12 times, according to Clarivate’s Web of Science.
The expression of concern highlights “suspected duplication of elements between figures 2b and 2c.”
The author [sic] admitted mistakes were made during preparation of the figures; however, since the paper was published in 2010, they were unable to provide the original raw data for figure 2c. Although the conclusions are not believed to be affected, the journal is issuing this expression of concern to alert readers that blots in figure 2c were inappropriately modified without disclosing the processing in the figure caption.
McMasters did not respond to our request for comment.
Carissa Gilman, director of editorial operations for Cancer, told Retraction Watch an “anonymous whistleblower” raised concerns about the paper by email. The person “said they had been aided by ImageTwin, an image integrity analytical tool,” Gilman told us.
Despite the inappropriate image modification, Gilman told us the editors did “not believe we have enough evidence that the paper should be retracted.”
The journal uses expressions of concern “if there are issues we believe cannot be resolved,” the representative continued. “In this case, since the original blot cannot be found, we cannot satisfactorily resolve this issue.”
A January 2024 comment in PubPeer from “Actinopolyspora biskrensis” on the 2010 paper points out possible duplications of signals and gel slices in the figures mentioned in the notice, as well as possible differential splicing between gel lanes.
The lead author, Jorge Gomez-Gutierrez, an associate professor at the University of Missouri School of Medicine in Columbia, Missouri, was unable to find the original blots “given the age of the paper,” according to Gilman.
Gomez-Gutierrez “agreed that the bands corresponding to actin were inadvertently duplicated during the figure preparation,” but stands by the paper “since they have been able to reproduce the same results in the intervening years multiple times using different cell lines,” according to Gilman. He did not respond to our request for comment.
McMasters has several other papers with PubPeer comments, including a second 2010 paper, “Developing adenoviral vectors encoding therapeutic genes toxic to host cells: Comparing binary and single-inducible vectors expressing truncated E2F-1.” Actinopolyspora pointed out image overlap in figure 3C of the paper.
Gomez-Gutierrez responded on PubPeer with original images. However, a second commenter, “Nerita vitiensis,” created an animation which “only confirms that Actinopolyspora biskrensis was correct – the images do indeed overlap.”
A second paper in Virology has comments on PubPeer pointing out image manipulation. Actinopolyspora noted in January that “[t]wo images in Figure 6D seem to overlap, but are described differently.”
A spokesperson from Elsevier, the publisher of Virology, has confirmed that the papers in Virology with PubPeer comments are currently “under investigation.”
In April, the MDPI journal Cancers issued a correction for “Temozolomide Enhances Triple-Negative Breast Cancer Virotherapy In Vitro,” a 2018 paper for which Gomez-Gutierrez and McMasters are corresponding authors.
The correction concerns an “error” in figure 1A of the paper, again following a PubPeer comment from Actinopolyspora. According to the correction, “the image of a crystal violet plate of MDA-MB-231 cells was inadvertently duplicated from a previous manuscript,” but a “new set of experiments was performed to replace the duplicated crystal violet plate and generate a new quantification graph.”
Another Cancers article by McMasters and Gomez-Gutierrez has PubPeer comments regarding potential image manipulation. MDPI didn’t respond to our request for comment about any plans to investigate further.
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The paragraph beginning with “The author ” should be inside quotation marks,
I would consider revising this sentence: “A second paper in Virology has comments on PubPeer pointing out image manipulation. Actinopolyspora noted in January that “[t]wo images in Figure 6D seem to overlap, but are described differently.””
I wouldn’t describe an image overlap of this type to be “image manipulation,” as it could be explained by an accidental error (one of the images may have been selected for the figure by accident), rather than an intent to mislead. My phrasing on PubPeer did not mention manipulation.