Effectiveness of mesothelin family proteins and osteopontin for malignant mesothelioma.

Malignant mesothelioma (MM) is an aggressive tumour with poor prognosis whose early diagnosis is difficult. Mesothelin, megakaryocyte potentiating factor (MPF) and osteopontin have attracted attention as biomarkers. The aim of the present review is to provide an overview regarding these candidate biomarkers for MM, and discuss their potential role in today's clinical practice. Mesothelin and MPF have good specificity but sub-optimal sensitivity for detection of MM, being negative both in the sarcomatoid histological sub-type and in almost half of epithelioid mesothelioma, especially in the early stages. Osteopontin is a marker of the duration of asbestos exposure, but lacks specificity for mesothelioma. Several patient characteristics influence the diagnostic accuracy of biomarkers and make the establishment of the "optimal" diagnostic threshold difficult. Mesothelin and MPF have proved useful in assessing response to treatment. Combining different markers together may lead to an improvement in diagnostic accuracy, but there is still need for research in this area. Extensive validation and further research is required to improve the use of serum markers in mesothelioma management. In the near future, their application in clinical practice is probably in monitoring response to therapy, rather than in guiding diagnostic decisions and risk assessment of asbestos-exposed populations.