Osteopontin

Osteopontin (OPN) is a protein released by many cell types, including inflamed tissues and some tumors, that can be measured in blood or pleural fluid. In people with asbestos exposure, elevated osteopontin has been studied as a possible biomarker for pleural disease and mesothelioma, though it is not specific enough to diagnose mesothelioma on its own.

Origin

Osteopontin was identified in bone in the 1980s and named from the Greek 'osteo' (bone) and Latin 'pons/pontis' (bridge), reflecting its role linking cells to the surrounding bone matrix. Researchers later found it is produced throughout the body and is elevated in inflammation and several cancers, prompting study as a cancer biomarker beginning in the early 2000s, notably a 2005 New England Journal of Medicine report by Pass and colleagues on asbestos-exposed individuals.

Significance in Asbestos Context

For patients with known asbestos exposure, osteopontin is one of several blood biomarkers (alongside mesothelin/SMRP and fibulin-3) that doctors may use to help evaluate suspicious imaging findings or monitor at-risk individuals. Elevated levels can support concern about mesothelioma but cannot confirm it. Diagnosis still requires imaging and tissue biopsy. Osteopontin can also rise with kidney disease, other cancers, bone disorders, and inflammation, so results must be interpreted alongside the full clinical picture. In a legal claim, biomarker results may appear in medical records and can corroborate the timeline of disease development, but they are supporting evidence rather than proof of causation.

Example Sentence

After a chest CT showed pleural thickening, the pulmonologist ordered osteopontin and mesothelin blood tests to help decide whether to proceed to a biopsy.

Related Terms

Biomarker, Mesothelin (SMRP), Fibulin-3, Mesothelioma, Pleural Effusion, Surveillance

Notes

• If you are in a high-risk group (heavy occupational exposure, prior asbestosis, or known pleural plaques), ask your pulmonologist or oncologist whether biomarker surveillance is appropriate and how often it should be repeated.
• Do not interpret a single elevated osteopontin result as a mesothelioma diagnosis. Ask what other conditions of yours (kidney disease, arthritis, other cancers) might be affecting the number.
• Request copies of all biomarker results (osteopontin, mesothelin/SMRP, fibulin-3) and keep them with your medical records; they can document the timing of disease onset for both treatment decisions and a future claim.
• Confirm whether your insurance covers biomarker testing in the surveillance setting, as coverage varies and these are not routine labs.