An EBC/Plasma miRNA Signature Discriminates Lung Adenocarcinomas From Pleural Mesothelioma and Healthy Controls

Our plain-English summary of An EBC/Plasma miRNA Signature Discriminates Lung Adenocarcinomas From Pleural Mesothelioma and Healthy Controls, by A. Faversani, C. Favero, L. Dioni, et al (Frontiers in Oncology, 2021).

The study

• Authors: A. Faversani, C. Favero, L. Dioni, A.C. Pesatori, V. Bollati, M. Montoli, V. Musso, A. Terrasi, N. Fusco, M. Nosotti, V. Vaira, A. Palleschi
• Journal: Frontiers in Oncology
• Published: 2021;11:643280
• Cited by: 18 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Background: Despite significant improvement in screening programs for cancers of the respiratory district, especially in at-risk subjects, early disease detection is still a major issue. In this scenario, new molecular and non-invasive biomarkers are needed to improve early disease diagnosis.

Methods: We profiled the miRNome in exhaled breath condensate (EBC) and plasma samples from fourteen patients affected by lung AdCa, nine healthy subjects. miRNA signatures were then analyzed in another neoplasia of the respiratory district, i.e. pleural mesothelioma (n = 23) and subjects previously exposed to asbestos were used as controls for this cohort (n = 19). Selected miRNAs were analyzed in purified pulmonary neoplastic or normal epithelial and stromal cell subpopulation from AdCa patients. Finally, the plasmatic miRNA signature was analyzed in a publicly available cohort of NSCLC patients for data validation and in silico analysis was performed with predicted miRNA targets using the multiMiR tool and STRING database.

Results: miR-597-5p and miR-1260a are significantly over-expressed in EBC from lung AdCa and are associated with AdCa. Similarly, miR-1260a is also up-regulated in the plasma of AdCa patients together with miR-518f-3p and correlates with presence of lung cancer, whereas let-7f-5p is under-expressed. Analysis of these circulating miRNAs in pleural mesothelioma cases confirmed that up-regulation of miR-518f-3p, -597-5p and -1260a, is specific for lung AdCa. Lastly, quantification of the miRNAs in laser-assisted microdissected lung tissues revealed that miR-518f-3p, 597-5p and miR-1260a are predominantly expressed in tumor epithelial cells. Validation analysis confirmed miR-518f-3p as a possible circulating biomarker of NSCLC. In silico analysis of the potentially modulated biological processes by these three miRNAs, shows that tumor bioenergetics are the most affected pathways.

Conclusions: Overall, our data suggest a 3-miRNAs signature as a non-invasive and accurate biomarker of lung AdCa. This approach could supplement the current screening approaches for early lung cancer diagnosis.

Copyright © 2021 Faversani, Favero, Dioni, Pesatori, Bollati, Montoli, Musso, Terrasi, Fusco, Nosotti, Vaira and Palleschi.

In plain English

This Milan study looked for small RNA molecules (microRNAs) in exhaled breath condensate and blood plasma that might signal lung adenocarcinoma. In 2015 and 2016 the authors recruited 14 male current or former smokers with early-stage lung adenocarcinoma scheduled for surgery, plus 9 matched healthy volunteers. In breath samples, miR-597-5p and miR-1260a were higher in patients than in controls (fold changes 2.4 and 9.9). In plasma, miR-1260a and miR-518f-3p were among those raised in patients. In tumor tissue, these three were found mostly in tumor cells. The authors then checked earlier data from 23 people with malignant pleural mesothelioma and 19 cancer-free people previously exposed to asbestos. The three raised microRNAs were not changed in mesothelioma breath samples, but let-7f-5p was lower in mesothelioma plasma. The article does not report quantitative measurements of asbestos exposure. The authors concluded that the three-microRNA signature could be specific for lung adenocarcinoma. They named small patient numbers as a limitation. The text says a validation check confirmed plasma miR-518f-3p, but the cited table prints p = 0.73 for its adjusted odds ratio.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Small case-control biomarker study (microRNA profiling of breath condensate and plasma), with comparison to a previously published mesothelioma dataset and a public lung cancer dataset
• Who was studied: 14 male patients with early-stage lung adenocarcinoma recruited from 2015 to 2016 at Fondazione IRCCS Ca' Granda, Milan, Italy, and 9 age- and gender-matched healthy volunteers. For comparison, an earlier series of 23 malignant pleural mesothelioma patients and 19 asbestos-exposed, cancer-free controls. Also a public dataset of 86 male NSCLC patients and 71 male controls.
• Exposure: The article reports no quantitative asbestos exposure measurements, fiber types or doses. Prior asbestos exposure is used only to describe the mesothelioma comparison controls as cancer-free people previously exposed to asbestos. The variables studied were microRNA levels in breath condensate, plasma and lung tissue.
• Main results:
  • In breath condensate, miR-597-5p and miR-1260a were higher in lung adenocarcinoma patients than in healthy controls (fold change 2.4 and 9.9).
  • Breath levels of these two microRNAs were associated with lung cancer: OR = 1.31 (SE 0.11, p = 0.019) for miR-597-5p and OR = 1.1 (SE 0.02, p = 0.031) for miR-1260a.
  • In plasma, miR-302b-3p, miR-518f-3p and miR-1260a were at least 4-fold higher in patients than in healthy controls. Twelve microRNAs, including let-7f-5p, were at least 2-fold lower.
  • In the validation step, the authors stated they confirmed significant changes in plasma miR-130b-3p, miR-302b-3p and miR-518f-3p, citing Table 2. Table 2's p values, which refer to odds ratios adjusted for age, smoking and BMI, are p = 0.03 for miR-130b-3p, p = 0.08 for miR-302b-3p and p = 0.73 for miR-518f-3p.
  • No microRNA was associated with the patients' tumor features, including tumor size or nodal metastasis.
  • In microdissected tissue from 13 of the 14 patients, miR-518f-3p, miR-597-5p and miR-1260a were more abundant in tumor cells than in the surrounding stroma or normal tissues.
  • In the public NSCLC dataset, let-7f-5p and miR-518f-3p showed only a trend in identifying lung adenocarcinoma patients.
  • In the malignant pleural mesothelioma cohort, miR-1260a, miR-518f-3p and miR-597-5p were not changed in breath condensate of patients compared with the asbestos-exposed controls.
  • In the mesothelioma cohort, plasma let-7f-5p was significantly lower in mesothelioma patients than in the asbestos-exposed controls.
  • A computer-based (in silico) analysis of predicted targets pointed to tumor energy metabolism (bioenergetics) as the pathway most affected by the three microRNAs.
• The authors' conclusion: The authors concluded that the three-microRNA signature (miR-1260a, miR-597-5p, miR-518f-3p) could be specific for lung adenocarcinoma. They concluded that lower let-7f-5p also characterizes malignant pleural mesothelioma.
• Limitations the authors state:
  • Small number of patients enrolled.
  • Larger cohorts and prospective studies on pre-diagnostic samples from at-risk people are needed before clinical use.
  • Breath condensate microRNAs could not be analyzed for two of the 14 adenocarcinoma patients because of poor RNA quality.

Topics

Medical terms in this study, explained in our Lexicon: Lung Adenocarcinoma, Pleural Mesothelioma, Biomarker, Lung Cancer.

Related studies

• Plasmatic extracellular vesicle microRNAs in malignant pleural mesothelioma and asbestos-exposed subjects suggest a 2-miRNA signature as potential biomarker of disease — T. Cavalleri, L. Angelici, et al. (2017)
• Four-miRNA Signature to Identify Asbestos-Related Lung Malignancies — L. Santarelli, S. Gaetani, et al. (2019)
• Serum Proteomics and Plasma Fibulin-3 in Differentiation of Mesothelioma From Asbestos-Exposed Controls and Patients With Other Pleural Diseases — S. Tsim, L. Alexander, et al. (2021)
• Asbestos and renal adenocarcinoma: a case-control study — M. Maclure (1987)
• Cigarette smoking associated with lung adenocarcinoma in situ in a large case-control study (SFBALCS) — P.M. Bracci, J. Sison, et al. (2012)
• Immunocytochemistry of CD146 is useful to discriminate between malignant pleural mesothelioma and reactive mesothelium — A. Sato, I. Torii, et al. (2010)

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