Exploration of identifying novel serum biomarkers for malignant mesothelioma using iTRAQ combined with 2D-LC-MS/MS

Our plain-English summary of Exploration of identifying novel serum biomarkers for malignant mesothelioma using iTRAQ combined with 2D-LC-MS/MS, by H. Xia, L. Feng, L. Lin, et al (Environmental Research, 2021).

The study

• Authors: H. Xia, L. Feng, L. Lin, Z. Jiang, J. Chen, W. Shi, S. Ying, M. Yu, L. Ju, L. Zhu, L. Shi, X. Zhang, J. Lou
• Journal: Environmental Research
• Published: 2021;193:110467
• Cited by: 4 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Malignant mesothelioma (MM) is an aggressive cancer linked to asbestos exposure. Its poor prognosis makes early diagnosis extremely important, which would provide an opportunity for early treatment and potentially changing outcomes. This study aimed to explore the underlying mechanisms of MM and discover novel noninvasive biomarkers for the diagnosis of malignant mesothelioma. Using Isobaric tags for relative and absolute quantitation (iTRAQ) combined with two-dimensional liquid chromatography/tandem mass spectrometry (2D LC-MS/MS), a total of 145 differentially expressed serum proteins were identified between MM patients and healthy controls. The identified proteins were further analyzed by bioinformatics, out of which three candidate biomarkers (Filamin A (FLNA), Fibulin 1 (FBLN1) and Thrombospondin-1 (TSP-1)) were validated in large cohorts of patients with asbestos-related diseases including MM patients by ELISA assay. Receiver operating characteristic (ROC) curve analysis showed that serum FLNA, FBLN1 and TSP-1 had high diagnostic values in distinguishing MM patients from healthy controls, individuals with asbestos exposure (AE), and patients with pleural plaques (PP) or asbestosis. Meanwhile, serum FBLN1 and TSP-1 possessed good diagnostic values in distinguishing asbestosis patients from healthy controls and individuals with AE. The combination of FLNA, FBLN1, and TSP-1 proteins had higher sensitivity and specificity in discriminating patients with MM, PP and asbestosis. Our findings indicated that analysis of serum proteome using iTRAQ is a feasible strategy for biomarker discovery, and serum FLNA, FBLN1 and TSP-1 may be promising candidates for diagnosis of malignant mesothelioma and screening of at-risk individuals.

Copyright © 2020 Elsevier Inc. All rights reserved.

In plain English

This laboratory study sought blood proteins to help diagnose malignant mesothelioma (MM). The authors first compared serum from 4 MM patients and 4 healthy controls using a mass-spectrometry method, iTRAQ. They found 145 proteins at different levels: 77 higher and 68 lower in the patients. They chose three: filamin A (FLNA), fibulin 1 (FBLN1) and thrombospondin-1 (TSP-1). They then measured them in 176 people from a historical asbestos processing area in Southeast China, 2014 to 2017. These were 40 unexposed controls, 42 workers exposed to asbestos for under 10 years and 40 for over 10 years (none with chest X-ray changes), 18 people with pleural plaques, 20 with asbestosis and 16 with MM. All MM cases were of the epithelioid type. In MM patients, FLNA was higher, and FBLN1 and TSP-1 lower, than in controls and exposed workers. With all three proteins combined, the area under the curve was 0.987 (95% confidence interval 0.963 to 1.000) against healthy controls and 0.933 (0.844 to 1.000) against asbestosis. This measures how well a test separates groups. The authors concluded the proteins could be potential biomarkers needing further confirmation.

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: Biomarker discovery and validation study: serum proteomic screening of a small discovery set, followed by ELISA measurement of three candidate proteins in a larger validation set compared across groups
• Who was studied: Discovery set: 4 MM patients and 4 matched healthy controls. Validation set: 176 serum samples from a historical asbestos processing area in Southeast China, 2014 to 2017. These were 40 healthy controls with no asbestos exposure, 42 workers exposed under 10 years and 40 exposed over 10 years (none with chest X-ray changes), 18 with pleural plaques alone, 20 with asbestosis and 16 with MM, all epithelioid.
• Exposure: Occupational asbestos exposure, grouped by duration (less than 10 years or more than 10 years); fiber types not stated. The measured markers were the serum proteins FLNA, FBLN1 and TSP-1.
• Main results:
  • In the discovery set (4 MM patients vs 4 healthy controls), 145 proteins differed in level: 77 up-regulated and 68 down-regulated in MM patients.
  • In the mass-spectrometry screen, FLNA was 5.86-fold higher, and FBLN1 and TSP-1 were 2.78-fold and 7.14-fold lower, in MM patients than in healthy controls.
  • In the validation set, serum FLNA in the MM group (mean 298.2 pg/ml, SD 90.0) was significantly higher than in the control group (P = 0.002), the group exposed under 10 years (P = 0.002) and the group exposed 10 years or more (P = 0.001). No difference in FLNA was found among the asbestos-related disease groups.
  • Serum FBLN1 (mean 435.8 ng/ml, SD 143.3) and TSP-1 (median 5897.3 ng/ml, IQR 6286.0) in the MM group were significantly lower than in the control, asbestos-exposed and pleural plaque groups (P less than 0.01). FBLN1 was also significantly lower in MM than in asbestosis (P less than 0.05). TSP-1 did not differ significantly between MM and asbestosis.
  • Age, sex, smoking and drinking habits had no significant influence on serum levels of the three proteins in multiple linear regression.
  • Distinguishing MM from healthy controls with single markers, the area under the curve (AUC) was 0.771 (95% CI 0.630 to 0.912) for FLNA, 0.922 (0.837 to 1.000) for FBLN1 and 0.951 (0.892 to 1.000) for TSP-1.
  • Using all three proteins as a panel, the AUC for distinguishing MM from healthy controls was 0.987 (95% CI 0.963 to 1.000), with sensitivity 0.933 and specificity 0.950.
  • Using all three proteins as a panel, the AUC for distinguishing MM from asbestosis was 0.933 (95% CI 0.844 to 1.000), with sensitivity 0.867 and specificity 0.944.
  • The authors reported that FBLN1 and TSP-1 separated asbestosis patients from healthy controls and from workers exposed under 10 years. The supporting supplementary table is not included in the text.
• The authors' conclusion: The authors concluded that serum FLNA, FBLN1 and TSP-1 could serve as potential biomarkers for diagnosing MM and screening at-risk individuals, that the three combined performed better than any one alone, and that the findings need further confirmation.
• Limitations the authors state:
  • Only a relatively small number of proteins were quantified, so some proteins relevant to the disease may have been missed.
  • The markers' clinical value needs checking in larger samples with different tumor stages and histologic subtypes.
  • The study did not compare the new markers with existing mesothelioma biomarkers.
  • Screening would produce false positives, some leading to unnecessary or risky procedures such as biopsies.
  • The cost of iTRAQ-based proteomics is still high.

Topics

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

Medical terms in this study, explained in our Lexicon: Biomarker, Malignant Mesothelioma, Asbestos Exposure, Prognosis, Pleural Plaques, Discovery.

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