Background: Soluble mesothelin (SM) and megakaryocyte potentiating factor (MPF) are serum biomarkers of mesothelioma. This study examined the effect of clinical covariates on biomarkers levels and their diagnostic and prognostic value.
Methods: Five hundred ninety-four participants were enrolled in a multicenter study, including 106 patients with mesothelioma and 488 control subjects. Multiple linear regression analyses were used to identify which covariates were independently associated with SM and MPF levels. The effect of these covariates on the diagnostic accuracy was evaluated with receiver operating characteristics curve analysis. In patients with mesothelioma, survival analysis was performed with Cox regression.
Results: SM and MPF levels were independently associated with age, glomerular filtration rate (GFR), and BMI in control subjects and with GFR and tumor stage in patients with mesothelioma. The diagnostic accuracy of SM and MPF was significantly affected by the distribution of these covariates in the study population. The patients with mesothelioma were best discriminated from the control subjects with either the youngest age, the highest GFR, or the largest BMI. Furthermore, the control subjects were significantly better differentiated from stage II to IV than from stage I mesothelioma. MPF, not SM, was an independent negative prognostic factor, but only if adjusted for the biomarker-associated covariates.
Conclusions: SM and MPF levels were affected by the same clinical covariates, which also had a significant impact on their diagnostic and prognostic value. To improve the interpretation of biomarker results, age, GFR, and BMI should be routinely recorded. Approaches to account for these covariates require further validation, as does the prognostic value of SM and MPF.