Earlier this year, Marc Halushka, a pathologist at Cleveland Clinic in Ohio, came across a review titled simply “MicroRNA,” an unusually short title in a big field. Looking deeper into the review, published in the Journal of Allergy and Clinical Immunology in 2018, Halushka found it had been cited more than 2,000 times. He thought this number “shockingly high,” given the article’s brevity and content.
Other, older reviews on microRNA from leaders in the field have been cited far more often, some even tens of thousands of times. But when searching “microRNA” on Google Scholar, the review with that single term as its title is the first result.
Halushka doesn’t think anything in the paper is wrong or out of date. But the citation was among those in a paper he was asked to review that he thought “was clearly a paper mill paper,” he told Retraction Watch. He suspects when people “who know nothing about microRNAs because they are just in the paper mill business” need to cite a review on the topic, they just use the top search result.
Such a scenario is a strong possibility. An analysis by David Robert Grimes, one of Retraction Watch’s first Sleuths in Residence, found that of the 2,046 papers citing the “MicroRNA” review in Elsevier’s Scopus database, 18 of them have been retracted. Many of the retraction notices describe recycled data and peer review concerns as reasons for the decision, which publishers often use to suggest paper mill activity. Six retractions came from Hindawi, an open-access publisher Wiley bought, then shut down, after it became clear paper mills had run amok in its journals.
In 2021, we covered the retraction of one of the papers that cited the review. “The authors stated that they published the paper without completely studying their work,” according to the notice.
The microRNA literature is a hotspot for paper mill activity, and researchers have quantified higher rates of retraction for papers on microRNA than related topics.
Marc Rothenberg, director of the Division of Allergy and Immunology at Cincinnati Children’s Hospital in Ohio, and the corresponding author of the review, declined to comment for this story. He is an associate editor of the Journal of Allergy and Clinical Immunology.
Grimes also analyzed the journals in which papers citing the “MicroRNA” review appeared. Most citations – 52 – came from articles in the International Journal of Molecular Sciences, an MDPI title. The journal with the next most papers citing the review, 39, was Bioengineered, a Taylor & Francis title which lost its standing in Clarivate’s Web of Science index earlier this year amid struggles to purge paper mill content from its pages. The journal suspended new submissions in July.
The remaining journals in the top five titles citing the “MicroRNA” review are all from the open-access publisher Frontiers.
In Grimes’ analysis of the affiliations of the authors citing the review, he found the 20 most frequent universities were all located in China. Just over 80 percent of the citations came from authors based at Chinese research centers.
We reached out to the authors of 20 papers citing the review to ask why they had done so. Only one responded.
“We included it because it is a concise, widely-read overview of microRNA biology in the context of immune and allergic diseases, which we felt would be helpful as a background primer for readers less familiar with the field,” Bailin Niu, of Chongqing University, told us. He and his colleagues had cited it in a review of the role of microRNAs in liver damage from sepsis published earlier this year in Pharmacological Research.
Jennifer Byrne, director of biobanking for New South Wales Health in Australia and a paper mill researcher, told us entities churning out scientific papers for pay could have incorporated a citation to the review into a reusable template, but “it’s difficult to be sure.”
If a citation to the review has been included in a template, the papers that cite it may have unexpected similarities, or there could be many papers citing the review in which “the citation seems unjustified,” she said.
Because the review is “quite technical,” citations would seem more relevant “when justifying experimental methods or discussing possible limitations of results,” Byrne said, not as a general overview of microRNA research.
“That said, if authors are simply opportunistically selecting this review as an accessible example of a miRNA review, we might also expect to see tangentially relevant citations, outside of any involvement of paper mills,” she said.
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