Soluble mesothelin-related protein in an asbestos-exposed population: the dust diseases board cohort study.

Rationale: Soluble mesothelin-related protein (SMRP) is raised in epithelial-type malignant mesothelioma (MM), but the utility of SMRP in screening for MM is unknown.

Objectives: We aimed to evaluate SMRP in an asbestos-exposed cohort.

Methods: A total of 538 subjects were studied. Those with elevated SMRP (> or =2.5 nM) underwent further investigation including positron emission tomography/computed tomography.

Measurements And Main Results: Mean (+/-SD) SMRP in healthy subjects exposed to asbestos (n = 223) was 0.79 (+/-0.45) nM. Fifteen subjects had elevated SMRP, of whom one had lung cancer, which was successfully resected. Another with lung cancer was undetected by SMRP. No subjects were diagnosed with MM. Mean SMRP in healthy subjects was significantly lower than in subjects with pleural plaques alone (P < 0.01).

Conclusions: This is the first large-scale prospective study of SMRP for screening for malignancy in asbestos-exposed individuals. A high false-positive rate was observed. SMRP seems unlikely to prove useful in screening for MM.