Diagnostic potential of miR-126, miR-143, miR-145, and miR-652 in malignant pleural mesothelioma

Our plain-English summary of Diagnostic potential of miR-126, miR-143, miR-145, and miR-652 in malignant pleural mesothelioma, by M. Andersen, M. Grauslund, J. Ravn, et al (The Journal of Molecular Diagnostics, 2014).

The study

• Authors: M. Andersen, M. Grauslund, J. Ravn, J.B. Sørensen, C.B. Andersen, E. Santoni-Rugiu
• Journal: The Journal of Molecular Diagnostics
• Published: 2014;16(4):418-30
• Cited by: 57 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Malignant pleural mesothelioma (MPM) is difficult to distinguish from reactive mesothelial proliferations (RMPs). It is uncertain whether miRNAs are useful biomarkers for differentiating MPM from RMPs. Thus, we screened with a quantitative RT-PCR (RT-qPCR)-based platform the expression of 742 miRNAs in formalin-fixed, paraffin-embedded, preoperative diagnostic biopsy samples, surgically resected MPM specimens previously treated with chemotherapy, and corresponding non-neoplastic pleura (NNP), from five patients. miR-126, miR-143, miR-145, and miR-652 were significantly down-regulated (≥twofold) in resected MPM and/or chemotherapy-naïve diagnostic tumor biopsy samples. The miRNA expression pattern was validated by RT-qPCR in a cohort of 40 independent MPMs. By performing binary logistic regression on the RT-qPCR data for the four miRNAs, the established four-miRNA classifier differentiated MPM from NNP with high sensitivity and specificity (area under the curve, 0.96; 95% CI, 0.92-1.00). The classifier's optimal logit(P) value of 0.62 separated NNP and MPM samples with a sensitivity of 0.95 (95% CI, 0.89-1.00), a specificity of 0.93 (95% CI, 0.87-0.99), and an overall accuracy of 0.94 (95% CI, 0.88-1.00). The level of miR-126 in MPM was inversely correlated with that of the known target, the large neutral amino acid transporter, small subunit 1 (r = -0.38; 95% CI, -0.63 to -0.06). Overall, these results indicate that these four miRNAs may be suitable biomarkers for distinguishing MPM from RMPs.

Copyright © 2014 American Society for Investigative Pathology and the Association for Molecular Pathology. Published by Elsevier Inc. All rights reserved.

In plain English

This laboratory study from Copenhagen University Hospital, Denmark, looked for small molecules called microRNAs that might help pathologists tell malignant pleural mesothelioma apart from non-cancerous (reactive) growth of the pleural lining. The authors first measured 742 microRNAs in tissue from five patients with epithelioid mesothelioma. They compared tumor biopsies, surgically removed tumor, and non-cancerous pleura from the same patients. They then checked selected microRNAs in tumor tissue from 40 patients, non-cancerous pleura from 14 of them, biopsies from 12 patients before chemotherapy, and pleura from 5 people with pneumothorax. Four microRNAs (miR-126, miR-143, miR-145 and miR-652) were significantly lower in mesothelioma samples than in non-cancerous pleura. Combined into one test, they correctly sorted 51 of 54 tumor and non-cancerous pleura samples (sensitivity 0.95, 95% CI 0.89 to 1.00; specificity 0.93, 95% CI 0.87 to 1.00). This combined test was not reported on the pneumothorax samples. A protein called LAT1 was higher in tumors and was inversely correlated with miR-126. The authors concluded these microRNAs may be promising diagnostic markers, but said a larger study and an independent blinded test are needed. The article did not report patients' asbestos exposure.

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: Laboratory diagnostic biomarker study: microRNA screening in a small set of tissue samples, followed by validation in a larger set of tissue samples, plus immunohistochemistry of two proteins
• Who was studied: Patients diagnosed and treated at Rigshospitalet, Copenhagen University Hospital, Denmark, 2004 to 2012. The screening set came from 5 patients (2 women, 3 men, aged 46 to 70) with epithelioid malignant pleural mesothelioma, stages II to IV. The validation set included surgical tumor specimens from 40 patients and matched non-neoplastic pleura from 14 of them. It also included preoperative diagnostic biopsies from a separate group of 12 chemotherapy-naive patients and pleural specimens from 5 patients with reactive mesothelial proliferation due to pneumothorax.
• Exposure: Not studied. The article measured microRNA and protein levels in tissue samples and did not report the patients' asbestos exposure.
• Main results:
  • In the screening of 742 microRNAs in the five-patient learning set, 14 microRNAs differed significantly in expression between tissue groups.
  • In the validation set, miR-126, miR-143, miR-145 and miR-652 were significantly lower in surgical mesothelioma samples and diagnostic biopsies than in non-neoplastic pleura.
  • In the 14 patients with matched tumor and non-neoplastic pleura, tumor tissue showed lower levels of all four microRNAs: miR-126 down 2.66-fold (P less than 0.05), miR-143 down 2.33-fold (P less than 0.05), miR-145 down 6.55-fold (P less than 0.001), and miR-652 down 2.28-fold (P less than 0.01).
  • Each microRNA alone separated mesothelioma from non-neoplastic pleura with these areas under the ROC curve: miR-126 0.78 (95% CI 0.64 to 0.92), miR-143 0.76 (95% CI 0.61 to 0.90), miR-145 0.93 (95% CI 0.85 to 1.02 in the text; 0.85 to 1.00 in Table 2 and Figure 4), and miR-652 0.89 (95% CI 0.80 to 0.99 in the text and Figure 4; 0.80 to 0.90 in Table 2).
  • The combined four-microRNA classifier separated mesothelioma from non-neoplastic pleura with an area under the ROC curve of 0.96 (95% CI 0.92 to 1.00 in the text; 0.91 to 1.00 in Figure 5).
  • The classifier correctly assigned 51 of 54 samples: 38 of 40 mesothelioma samples tested positive and 13 of 14 non-neoplastic pleura samples tested negative. Sensitivity was 0.95 (95% CI 0.89 to 1.00), specificity 0.93 (95% CI 0.87 to 1.00), and overall accuracy 0.94 (95% CI 0.88 to 1.00).
  • Among 36 mesothelioma patients analyzed for survival, a low classifier score was associated with poorer overall survival (P less than 0.05, log-rank test).
  • Biphasic mesotheliomas (22) showed significantly higher miR-126 and miR-145 and lower miR-193a-3p than epithelioid mesotheliomas (18).
  • The protein LAT1 had a median H score of 2 in mesothelioma samples, significantly higher than the median of 0.5 in non-neoplastic pleura. The difference from the pneumothorax samples (median 1) was not significant.
  • Across non-neoplastic pleura, mesothelioma and pneumothorax samples, LAT1 levels were inversely correlated with miR-126 levels (Spearman r = -0.38; CI -0.63 to -0.06 as printed in Figure 8).
• The authors' conclusion: The authors concluded that the four microRNAs can be combined into a diagnostic classifier for malignant pleural mesothelioma. They believe microRNAs may be promising diagnostic biomarkers, and that an assay combining microRNA detection with protein staining of their targets may improve the distinction between mesothelioma and reactive mesothelial proliferation.
• Limitations the authors state:
  • The number of samples was limited, and a larger study is needed to confirm the results.
  • The classifier needs further validation in an independent blinded test set.
  • Preliminary data (not shown) indicated that accuracy dropped significantly in samples with less than 50% tumor cell content.
  • LAT1 has not been confirmed as a target of miR-126 in mesothelioma; experiments in mesothelioma cell lines are needed.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Lung cancer, Mesothelioma.

Medical terms in this study, explained in our Lexicon: Pleural Mesothelioma, Biomarker, Biopsy, Chemotherapy, Pleura.

Related studies

• Are differentially expressed microRNAs useful in the diagnostics of malignant pleural mesothelioma? — M. Andersen, M. Grauslund, et al. (2012)
• MicroRNA signature of malignant mesothelioma with potential diagnostic and prognostic implications — S. Busacca, S. Germano, et al. (2010)
• miR-193a-3p is a potential tumor suppressor in malignant pleural mesothelioma — M. Williams, M.B. Kirschner, et al. (2015)
• ZIC1 is silenced and has tumor suppressor function in malignant pleural mesothelioma — Y.Y. Cheng, M.B. Kirschner, et al. (2013)
• Increased circulating miR-625-3p: a potential biomarker for patients with malignant pleural mesothelioma — M.B. Kirschner, Y.Y. Cheng, et al. (2012)
• miR-1 induces growth arrest and apoptosis in malignant mesothelioma — Y. Xu, M. Zheng, et al. (2013)

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