Osteopontin, asbestos exposure and pleural plaques: a cross-sectional study
1 Department of Environmental Medicine and Public Health, Padua University, Padua, Italy
2 Occupational Health Service, Primary Care Trust 12, Venice, Italy
3 ABO Association, Regional Centre for the Study of Biological Markers of Malignancy, Department of Clinical Pathology, Local Health Authority 12, Venice, Italy
4 Occupational Health Service, Occupational Health Service, Primary Care Trust 13, Dolo (Venice), Italy
5 Envirosafe Training and Consultants, P.O. Box 114022, Pittsburgh, PA 15239-0522, USA
6 Regional Epidemiological Service, Veneto Region, Castelfranco Veneto (TV), Italy
7 Imperial College London, School of Public Health, St. Mary's Campus, London, UK
8 Regional Centre for the Study of Biological Markers of Malignancy, Department of Clinical Pathology, Primary Care Trust 12 - Venice, Italy
BMC Public Health 2011, 11:220 doi:10.1186/1471-2458-11-220Published: 8 April 2011
Osteopontin (OPN) is a plasma protein/cytokine produced in excess in several malignancies. In a recent study OPN was reported as being related to the duration of asbestos exposure and presence of benign asbestos-related diseases; however, it was unclear whether this protein was an indicator of exposure or effect.
In 193 workers, 50 with pleural plaques (PP), in whom different indicators of past asbestos exposure were estimated, OPN plasma levels were assessed using commercial quantitative sandwich enzyme immunoassays according to the manufacturer's instructions.
Osteopontin increased with increasing age and several aspects of asbestos exposure, without differences related to the presence of pleural plaques. At multivariable regression analysis, the explanatory variables with a significant independent influence on OPN were length of exposure (positive correlation) and time elapsed since last exposure (positive correlation).
Since asbestos in lung tissue tends to wane over time, OPN should decrease (rather than increase) with time since last exposure. Therefore, OPN cannot be a reliable biomarker of exposure nor effect (presence of pleural plaques).