Last year, Boris Ratnikov was reading a paper and saw a familiar image.
He quickly realized: The image was from a 2012 paper he’d written, but wasn’t cited. The 2016 Cell Metabolism paper he was reading had copied a figure from his 2012 PLOS ONE paper without referencing it.
In September 2016, Ratnikov, who is based at Sanford-Burnham-Prebys Medical Discovery Institute, in La Jolla, California, emailed an editor at Cell Metabolism to express his concern about the duplication and omitted citation.
Although the journal told us it “carefully investigated Dr Ratnikov’s concerns,” the editors ultimately did not think the literature needs correcting.
Does failing to cite a paper constitute plagiarism?
Ratnikov would say it does, though the journal would disagree. According to Ratnikov, the 2016 paper copied original materials from his 2012 PLOS ONE paper and thus “plagiarized our work by not citing it.”
The editors at Cell Metabolism, however, believe that the figure in question was meant as “a general overview,” rather than “an adaptation” of the figure from Ratnikov’s paper, and thus citing the 2012 paper was not necessary.
Here are the figures in question (click to enlarge; post continues below):
To cite or not to cite?
Forwarded email correspondences between Ratnikov, the journal, and the corresponding author on the Cell Metabolism paper, Jeffrey Settleman, provide further insights about what went on.
According to Ratnikov, the PLOS ONE paper, “Functional Specialization in Proline Biosynthesis of Melanoma,” published in September 2012, was the first to define and characterize a particular pathway that promotes tumor cell growth. Ratnikov and his co-authors depicted how that pathway works in Figure 5 of the paper. In the 2016 Cell Metabolism paper, “Proline Starvation Induces Unresolved ER Stress and Hinders mTORC1-Dependent Tumorigenesis,” the authors depicted the same pathway in Figure 2A.
In July 2017, Ratnikov also informed the journal:
Before I contacted Cell Metabolism with my inquiry I had consulted with the Office of intellectual property at our institution and they agreed that lack of referencing of our work in Dr. Settleman’s paper was a clear breach of scientific ethics and recommended I contacted Cell Metabolism to rectify the situation.
To rectify the situation, Ratnikov told us that Cell Metabolism could simply include a direct reference to the PLOS ONE paper where appropriate or the authors could modify “their figure 2A and the relevant text to exclude the information that can only be found in our work and not in the review article they used for citation.”
In October 2016, a senior editor at Cell Metabolism, Anne Granger, responded to Ratnikov’s initial complaint, explaining that “it may be hard at times to include all the relevant literature in a paper as space is limited.” The editor asked Ratnikov to contact the corresponding author of the Cell Metabolism paper, Settleman, to discuss the matter further.
In March 2017, Ratnikov contacted Settleman, a researcher at a biotech company in San Francisco, Calico Life Sciences, about the oversight. Settleman attempted to explain why he had not referenced Ratnikov’s article in his 2016 Cell Metabolism paper:
We are certainly aware of your study. As you have probably noticed, our publication was in the Short Article format for Cell Metabolism. As such, the number of references allowed is quite limited. In fact, our initial submission included many references that ultimately had to be excluded.
Settleman explained why Ratnikov’s article did not make the cut. Given the limited space for references, Settleman said that he and his co-authors decided to reference a review in Frontiers in Oncology, published in June 2012, which cites Ratnikov’s PLOS ONE study:
…we referenced a review article, which includes a citation that directs readers to the relevant work from your group. In my experience, this is very often how primary scientific findings are referenced.
The PLOS ONE paper has been cited 23 times, according to Clarivate Analytics’ Web of Science, and the work was supported by a grant from the National Institutes of Health. The Frontiers in Oncology review, “The proline regulatory axis and cancer,” has been cited 36 times.
A case of plagiarism?
When citing previous work, what’s appropriate? According to Miguel Roig, a professor of psychology at St. John’s University who has written about plagiarism and duplication in academic writing:
… that scenario would, in my view, probably constitute plagiarism (it always depends on the exact details of the case).
Roig — a member of the board of directors of our parent non-profit organization — explained:
In this type of case, the question for me is this: In writing a portion of a literature review, why would an author misappropriate material from the primary source to summarize that work, but then only cite the review article that describes the same work? I think the answer is obvious.
If an author copies verbatim, or even paraphrases/summarizes, from primary source A, that author has an ethical obligation to cite source A, period. The same applies if the author in question is writing about a novel idea described in source A. Even if no verbatim copying has taken place, source A must be credited with that idea. Citing only source B, which had also summarized A (and, presumably, cited it) misleads the reader as to the true source of the author’s material.
He also noted:
When writing literature reviews some authors may simultaneously rely on review articles, which may help the author place the work in question in a broader context, as well as on the primary work. In such cases, authors must cite both works as both served as sources for the author’s literature review.
In March, Ratnikov emailed the editors at Cell Metabolism again and on June 2, the senior editor, Granger, addressed Ratnikov’s concerns:
While we see where you are coming from, based on our evaluation of Figure 5 from your paper and figure 2A of their paper and our editorial discussions, our impression is that the Settleman figure was meant as a general overview of the entire proline biosynthesis pathway, rather than an adaptation of the figure from your paper. We also note that metabolic diagrams frequently bear some similarity to each other and are often embedded within figures in order to assist the reader as an overview. Although our preference at the journal is for citing the primary literature whenever possible, we feel that a reference to a review article which covers the different aspects of proline biosynthesis rather than several articles each covering individual aspects of the pathway is sufficient in this particular case.
Ratnikov quickly responded, again explaining that “the entire proline biosynthesis pathway was characterized in our paper and nowhere else.”
On June 26, Ratnikov received an email from the editor-in-chief of Cell Metabolism, Nikla Emambokus:
I have reviewed the figures from both Dr. Settleman’s and your PLoS One paper, “Functional specialization in proline biosynthesis of melanoma”, and discussed your conceptual concern with an external expert in the field, as well as our legal counsels. Based on our investigation, we do not see a case of publishing ethics infringement either on the part of Dr. Settleman or of Cell Metabolism.
Ratnikov responded the same day, asking for more information about the decision.Emambokus wrote back the next day:
We consider this matter closed.
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