Identification of novel autoantibodies for detection of malignant mesothelioma

Our plain-English summary of Identification of novel autoantibodies for detection of malignant mesothelioma, by X. Zhang, W. Shen, X. Dong, et al (PloS One, 2013).

The study

• Authors: X. Zhang, W. Shen, X. Dong, J. Fan, L. Liu, X. Gao, K.H. Kernstine, L. Zhong
• Journal: PloS One
• Published: 2013;8(8):e72458
• Cited by: 13 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Background: The malignant mesothelioma (MM) survival rate has been hampered by the lack of efficient and accurate early detection methods. The immune system may detect the early changes of tumor progression by responding with tumor-associated autoantibody production. Hence, in this study, we translated the humoral immune response to cancer proteins into a potential blood test for MM.

Methodology/principal Findings: A T7 phage MM cDNA library was constructed using MM tumor tissues and biopanned for tumor-associated antigens (TAAs) using pooled MM patient and normal serum samples. About 1008 individual phage TAA clones from the biopanned library were subjected to protein microarray construction and tested with 53 MM and 52 control serum samples as a training group. Nine candidate autoantibody markers were selected from the training group using Tclass system and logistic regression statistical analysis, which achieved 94.3% sensitivity and 90.4% specificity with an AUC value of 0.89 in receiver operating characteristic analysis. The classifier was further evaluated with 50 patient and 50 normal serum samples as an independent blind validation, and the sensitivity of 86.0% and the specificity of 86.0% were obtained with an AUC of 0.82. Sequencing and BLASTN analysis of the classifier revealed that five of these nine candidate markers were found to have strong homology to cancer related proteins (PDIA6, MEG3, SDCCAG3, IGHG3, IGHG1).

Conclusions/significance: Our results indicated that using a panel of 9 autoantibody markers presented a promising accuracy for MM detection. Although the results need further validation in high-risk groups, they provided the potentials in developing a serum-based assay for MM diagnosis.

In plain English

This laboratory study looked for blood antibodies that might signal malignant mesothelioma (MM). The authors built a phage cDNA library from tumor tissue of 5 MM patients, screened it with pooled serum from 5 patients and 5 normal controls, and printed 1008 randomly picked phage clones on test slides. All samples came from the National Mesothelioma Virtual Bank. In a training group of 53 MM patients and 52 controls with no cancer history, the authors chose a panel of 9 markers. Together these showed 94.3% sensitivity (share of patients flagged) and 90.4% specificity (share of controls cleared), with an AUC of 0.89. Single markers performed less well. In a separate group of 50 patients and 50 controls, the panel showed 86.0% sensitivity and 86.0% specificity (AUC 0.82). Five of the 9 markers resembled proteins that other studies had linked to cancer. All patients in the training and validation groups had stage III or IV disease; no one's asbestos exposure was reported. The authors concluded the panel gave encouraging accuracy but needs further validation in high-risk groups. They cautioned it may not hold in larger samples or early-stage disease.

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 biomarker discovery study comparing blood serum from mesothelioma patients and normal controls. It had a training set and a separate validation set. Phage clones came from a T7 phage cDNA library made from tumor tissue and were tested on protein microarrays.
• Who was studied: 5 MM tissue samples and 215 serum samples (108 MM patients and 107 normal controls) from the National Mesothelioma Virtual Bank, with Institutional Review Board approval at the University of Pennsylvania Medical Center. Pooled serum from 5 patients and 5 controls was used for library screening. The training set was 53 patients (12 female, 41 male, aged 53 to 85; 21 stage III, 32 stage IV) and 52 controls with no cancer history. The validation set was 50 patients (10 female, 40 male, aged 51 to 87; 19 stage III, 31 stage IV) and 50 controls. Stages were not reported for the tissue donors or for the patients whose sera were used in library screening. Collection dates were not given.
• Exposure: The study did not measure asbestos exposure. It measured serum autoantibody reactivity against 1008 phage clones randomly selected from the screened mesothelioma tumor cDNA library.
• Main results:
  • Training set (53 MM patients, 52 controls): the combined 9-marker panel had sensitivity of 94.3%, specificity of 90.4% and AUC of 0.89.
  • Training set: in cross-validation the 9-marker panel had a classifying accuracy of 95.0% and a stability of 94.1%.
  • Training set: each single marker performed less well than the combined panel. Individual AUCs in Table 2 ranged from 0.60 to 0.76.
  • Independent validation set (50 MM patients, 50 controls not used before): the panel had sensitivity of 86.0%, specificity of 86.0% and AUC of 0.82.
  • Sequencing showed that 5 of the 9 markers had known roles associated with cancer development: PDIA6, MEG3, SDCCAG3, IGHG1 and IGHG3.
  • Reproducibility: across three replicate slides of each serum sample, the coefficients of variation for the 9 markers ranged from 8% to 15%.
• The authors' conclusion: The authors concluded that the 9-autoantibody panel provided encouraging accuracy for MM detection. They said the results need further validation in high-risk groups, but offer the potential to develop a serum-based assay for MM diagnosis.
• Limitations the authors state:
  • The high laboratory accuracy may not hold with larger samples or in patients with early-stage MM.
  • Early-stage MM samples are difficult to obtain.
  • The phage library was not exhaustively screened, so some predictive markers have likely not been identified.
  • Protein microarrays may suffer from two-channel staining bias and chip-to-chip variability. The authors used normalization methods to reduce these.

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: Mesothelioma.

Related studies

• p53 autoantibodies in patients with malignant mesothelioma: stability through disease progression — J. Creaney, B.M. McLaren, et al. (2001)
• Autoantibodies from mice exposed to Libby amphibole asbestos bind SSA/Ro52-enriched apoptotic blebs of murine macrophages — D.J. Blake, S.A. Wetzel, et al. (2008)
• Alteration of fibroblast phenotype by asbestos-induced autoantibodies — J.C. Pfau, S. Li, et al. (2011)
• Asbestos-associated mesothelial cell autoantibodies promote collagen deposition in vitro — K.M. Serve, B. Black, et al. (2013)
• Libby amphibole-induced mesothelial cell autoantibodies promote collagen deposition in mice — J. Gilmer, K. Serve, et al. (2016)
• Libby amphibole-induced mesothelial cell autoantibodies bind to surface plasminogen and alter collagen matrix remodeling — R. Hanson, C. Evilia, et al. (2016)

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