Osteopontin levels in an asbestos-exposed population

Our plain-English summary of Osteopontin levels in an asbestos-exposed population, by E.K. Park, P.S. Thomas, A.R. Johnson, et al (Clinical Cancer Research, 2009).

The study

• Authors: E.K. Park, P.S. Thomas, A.R. Johnson, D.H. Yates
• Journal: Clinical Cancer Research
• Published: 2009;15(4):1362-6
• Cited by: 23 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Purpose: Serum osteopontin levels in patients with malignant mesothelioma have been reported to be higher than in healthy subjects. This study assessed serum osteopontin levels in an asbestos-exposed population to test whether nonmalignant asbestos-related disorders could influence osteopontin levels.

Experimental Design: This cross-sectional study evaluated serum osteopontin levels in 525 male subjects. Subjects were classified into six different diagnostic groups, including asbestosis (n=23), silicosis (n=20), diffuse pleural thickening (n=110), asbestosis and diffuse pleural thickening (n=13), pleural plaques (n=142), and healthy subjects with a history of asbestos exposure (n=217).

Results: Mean serum osteopontin levels differed among the six groups (P<0.0001). Mean osteopontin values of the healthy individuals exposed to asbestos were significantly different from that of subjects with asbestosis (P<0.001) and diffuse pleural thickening (P<0.001). There was a significant difference in mean serum levels of osteopontin in healthy individuals exposed to asbestos (n=217) compared with the group mean of all subjects with asbestos-related disorders (n=288; P<0.0001).

Conclusions: Our results suggest that osteopontin levels are elevated in subjects with asbestos-related disorders without malignant mesothelioma. These data indicate that osteopontin, although reported to be useful for detecting malignant mesothelioma in asbestos-exposed individuals, may be influenced by nonmalignant processes.

In plain English

This cross-sectional study measured the blood protein osteopontin in 525 men attending the Workers' Compensation (Dust Diseases) Board of New South Wales, Australia, for routine screening between January and November 2006. The men were grouped as otherwise healthy but asbestos-exposed (217), pleural plaques (142), diffuse pleural thickening (110), asbestosis (23), asbestosis with diffuse pleural thickening (13), or silicosis (20). Average levels differed significantly among the groups. The healthy asbestos-exposed men averaged 24.1 ng/mL. That was significantly lower than men with asbestosis (70.2) or diffuse pleural thickening (46.2), and lower than all 288 men with asbestos-related disorders combined (40.4). Levels were associated with age. Seventy-two men (13.7%) were above a cutoff of 62.4 ng/mL taken from an earlier study. None showed evidence of mesothelioma on imaging, and one was later found to have lung cancer. The authors concluded that osteopontin's usefulness for detecting mesothelioma in this population is likely limited. They noted that asbestos exposure was not quantified and that confounding, for example by atherosclerosis, was possible.

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 study of serum osteopontin, drawn from a larger prospective cohort study
• Who was studied: 525 men with asbestos or other dust exposure attending the Workers' Compensation (Dust Diseases) Board of New South Wales, Australia, for routine screening and compensation examinations, January to November 2006. Groups: healthy asbestos-exposed (217), pleural plaques (142), diffuse pleural thickening (110), asbestosis (23), asbestosis and diffuse pleural thickening (13), silicosis (20)
• Exposure: Documented occupational asbestos exposure (fiber types and amounts not reported). The silicosis group had occupational silica exposure.
• Main results:
  • Mean serum osteopontin levels differed significantly among the six diagnostic groups (P < 0.0001)
  • Mean levels (plus or minus SD) did not differ between healthy asbestos-exposed men (24.1 plus or minus 25.6 ng/mL) and men with silicosis (20.9 plus or minus 16.6 ng/mL; P > 0.05)
  • Mean levels in asbestos-related disorder groups were: asbestosis 70.2 plus or minus 41.5 ng/mL; diffuse pleural thickening 46.2 plus or minus 61.5 ng/mL; asbestosis and diffuse pleural thickening 26.4 plus or minus 17.2 ng/mL; pleural plaques 32.4 plus or minus 43.4 ng/mL
  • Healthy asbestos-exposed men had significantly lower mean levels than men with asbestosis (P < 0.001) and men with diffuse pleural thickening (P < 0.001)
  • Healthy asbestos-exposed men (n = 217) averaged 24.1 plus or minus 25.6 ng/mL versus 40.4 plus or minus 51.3 ng/mL for all men with asbestos-related disorders (n = 288); P < 0.0001
  • Mean osteopontin in the asbestosis group differed significantly from the silicosis (P < 0.01), asbestosis and diffuse pleural thickening (P < 0.05), and pleural plaques (P < 0.001) groups
  • Across the cohort, osteopontin was positively associated with age but not significantly correlated with BMI or smoking status
  • 72 of 525 men (13.7%) had osteopontin at or above the 62.4 ng/mL cutoff from an earlier study: 20 healthy asbestos-exposed, 1 silicosis, 11 asbestosis, 21 diffuse pleural thickening, 19 pleural plaques
  • None of these 72 men had evidence of malignant mesothelioma on chest radiography and computed tomography
  • One man with an elevated level was later found to have lung cancer; his osteopontin level was 117.6 ng/mL
• The authors' conclusion: The authors concluded that osteopontin levels are higher in men with nonmalignant asbestos-related disease and that osteopontin's usefulness for detecting malignant mesothelioma in this population is likely to be limited
• Limitations the authors state:
  • Occupational histories were not detailed enough to quantify asbestos exposure, so a link between osteopontin and degree of exposure could not be confirmed
  • The findings may be due to confounding, since factors such as atherosclerosis are known to raise osteopontin; the association with age supports this
  • Numbers were small for the asbestosis comparisons
  • The study was not designed to evaluate other pleural malignancies, and no mesotheliomas were detected

Topics

Medical terms in this study, explained in our Lexicon: Osteopontin, Malignant Mesothelioma, Silicosis, Diffuse Pleural Thickening, Pleural Plaques, Asbestos Exposure.

Related studies

• Preliminary study of positron emission tomography/computed tomography and plasma osteopontin levels in patients with asbestos-related pleural disease — S. Kurata, M. Ishibashi, et al. (2010)
• Plasma versus serum levels of osteopontin and mesothelin in patients with malignant mesothelioma--which is best? — J. Creaney, D. Yeoman, et al. (2011)
• Comparison between plasma and serum osteopontin levels: usefulness in diagnosis of epithelial malignant pleural mesothelioma — A. Cristaudo, R. Foddis, et al. (2010)
• Changes of mesothelin and osteopontin levels over time in formerly asbestos-exposed power industry workers — M.K. Felten, K. Khatab, et al. (2014)
• Soluble mesothelin related peptides (SMRP) and osteopontin as protein biomarkers for malignant mesothelioma: analytical validation of ELISA based assays and characterization at mRNA and protein levels — A.J. Rai, R.M. Flores, et al. (2010)
• Osteopontin, asbestos exposure and pleural plaques: a cross-sectional study — G. Mastrangelo, G. Marangi, et al. (2011)

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