Chemical characterization of exhaled breath to differentiate between patients with malignant plueral mesothelioma from subjects with similar professional asbestos exposure

Our plain-English summary of Chemical characterization of exhaled breath to differentiate between patients with malignant plueral mesothelioma from subjects with similar professional asbestos exposure, by G. de Gennaro, S. Dragonieri, F. Longobardi, et al (Analytical and Bioanalytical Chemistry, 2010).

The study

• Authors: G. de Gennaro, S. Dragonieri, F. Longobardi, M. Musti, G. Stallone, L. Trizio, M. Tutino
• Journal: Analytical and Bioanalytical Chemistry
• Published: 2010;398(7-8):3043-50
• Cited by: 55 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Malignant pleural mesothelioma (MPM) is an aggressive tumour whose main aetiology is the long-term exposure to asbestos fibres. The diagnostic procedure of MPM is difficult and often requires invasive approaches; therefore, it is clinically important to find accurate markers for MPM by new noninvasive methods that may facilitate the diagnostic process and identify patients at an earlier stage. In the present study, the exhaled breath of 13 patients with histology-established diagnosis of MPM, 13 subjects with long-term certified professional exposure to asbestos (EXP) and 13 healthy subjects without exposure to asbestos (healthy controls, HC) were analysed. An analytical procedure to determine volatile organic compounds by sampling of air on a bed of solid sorbent and thermal desorption GC-MS analysis was developed in order to identify the compounds capable of discriminating among the three groups. The application of univariate (ANOVA) and multivariate statistical treatments (PCA, DFA and CP-ANN) showed that cyclopentane and cyclohexane were the dominant variables able to discriminate among the three groups. In particular, it was found that cyclohexane is the only compound able to differentiate the MPM group from the other two; therefore, it can be a possible marker of MPM. Cyclopentane is the dominant compound in the discrimination between EXP and the other groups (MPM and HC); then, it can be considered a good indicator for long-term asbestos exposure. This result suggests the need to perform frequent and thorough investigations on people exposed to asbestos in order to constantly monitor their state of health or possibly to study the evolution of disease over time.

In plain English

This study tested whether chemicals in exhaled breath could tell apart three groups of 13 adults each. The groups were patients with malignant pleural mesothelioma, people with long-term certified work exposure to asbestos who had not developed the disease (with radiological signs of pleural plaques and/or benign asbestos pleural effusion), and healthy people with no history of work exposure to asbestos. The authors measured volatile organic compounds in breath samples. Cyclohexane was the only compound that differed significantly among all three groups. Its median level was 251.79 ng/L in the mesothelioma patients, 69.31 ng/L in the exposed group and 33.08 ng/L in healthy controls. Cyclopentane, methyl-octane and dimethyl-nonane set the exposed group apart from the other two. When each person was classified by a model built without them, a discriminant analysis correctly placed 84.6% of subjects, a version using 11 selected compounds 94.9%, and a neural network 87%. The authors concluded that cyclohexane could be a possible marker of mesothelioma and cyclopentane a good indicator of long-term asbestos exposure. They also noted the small number of samples.

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: Cross-sectional case-control study comparing exhaled breath chemistry among three groups
• Who was studied: 39 adult volunteers aged 45 to 80 in three groups of 13: patients with histology-established malignant pleural mesothelioma (MPM), subjects without MPM but with long-term professional asbestos exposure (EXP), and healthy controls with a negative history of professional asbestos exposure (HC). Study dates are not given.
• Exposure: Long-term professional (occupational) asbestos exposure in the MPM and EXP groups; the EXP group had radiological signs of pleural plaques and/or benign asbestos pleural effusion. Fiber types, jobs and doses are not reported. What was measured was volatile organic compounds in exhaled breath.
• Main results:
  • Cyclohexane was the only compound whose levels differed significantly among all three groups.
  • Median cyclohexane: 251.79 ng/L in MPM patients, 69.31 ng/L in asbestos-exposed subjects, 33.08 ng/L in healthy controls.
  • In the asbestos-exposed group, levels of cyclopentane, methyl-octane and dimethyl-nonane differed significantly from both the MPM and healthy control groups.
  • Discriminant function analysis separated all three groups completely on the data used to build it (100% recognition for each group).
  • In leave-one-out cross-validation, discriminant function analysis correctly predicted the group of 84.6% of subjects.
  • In that cross-validation, five MPM patients were misclassified (two as healthy controls, three as exposed), and one healthy control was misclassified as exposed.
  • A stepwise discriminant analysis using 11 compounds had 97.4% recognition and 94.9% cross-validated prediction. Two MPM patients were misclassified as healthy controls.
  • A neural network (CP-ANN) had a cross-validated prediction ability of 87% for the three groups. Five of the 39 subjects were misclassified.
  • Principal component analysis showed only partial separation of the groups, with overlapping clusters.
  • Asbestos-exposed subjects were slightly older than healthy controls.
• The authors' conclusion: The authors concluded that cyclohexane is the only compound that differentiated the MPM group from the other two and can be considered a possible marker of the disease. They also concluded that cyclopentane, which distinguished the exposed group, can be considered a good indicator of long-term asbestos exposure.
• Limitations the authors state:
  • The authors acknowledged that the number of samples analysed was small.

Topics

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

Medical terms in this study, explained in our Lexicon: Mesothelioma, Asbestos Exposure, Pleural Mesothelioma, Histology.

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