Fibulin-3 as a blood and effusion biomarker for pleural mesothelioma

BACKGROUND

New biomarkers are needed to detect pleural mesothelioma at an earlier stage and to individualize treatment strategies. We investigated whether fibulin-3 in plasma and pleural effusions could meet sensitivity and specificity criteria for a robust biomarker.

METHODS

We measured fibulin-3 levels in plasma (from 92 patients with mesothelioma, 136 asbestos-exposed persons without cancer, 93 patients with effusions not due to mesothelioma, and 43 healthy controls), effusions (from 74 patients with mesothelioma, 39 with benign effusions, and 54 with malignant effusions not due to mesothelioma), or both. A blinded validation was subsequently performed. Tumor tissue was examined for fibulin-3 by immunohistochemical analysis, and levels of fibulin-3 in plasma and effusions were measured with an enzyme-linked immunosorbent assay.

RESULTS

Plasma fibulin-3 levels did not vary according to age, sex, duration of asbestos exposure, or degree of radiographic changes and were significantly higher in patients with pleural mesothelioma (105±7 ng per milliliter in the Detroit cohort and 113±8 ng per milliliter in the New York cohort) than in asbestos-exposed persons without mesothelioma (14±1 ng per milliliter and 24±1 ng per milliliter, respectively; P<0.001). Effusion fibulin-3 levels were significantly higher in patients with pleural mesothelioma (694±37 ng per milliliter in the Detroit cohort and 636±92 ng per milliliter in the New York cohort) than in patients with effusions not due to mesothelioma (212±25 and 151±23 ng per milliliter, respectively; P<0.001). Fibulin-3 preferentially stained tumor cells in 26 of 26 samples. In an overall comparison of patients with and those without mesothelioma, the receiver-operating-characteristic curve for plasma fibulin-3 levels had a sensitivity of 96.7% and a specificity of 95.5% at a cutoff value of 52.8 ng of fibulin-3 per milliliter. In a comparison of patients with early-stage mesothelioma with asbestos-exposed persons, the sensitivity was 100% and the specificity was 94.1% at a cutoff value of 46.0 ng of fibulin-3 per milliliter. Blinded validation revealed an area under the curve of 0.87 for plasma specimens from 96 asbestos-exposed persons as compared with 48 patients with mesothelioma.

CONCLUSIONS

Plasma fibulin-3 levels can distinguish healthy persons with exposure to asbestos from patients with mesothelioma. In conjunction with effusion fibulin-3 levels, plasma fibulin-3 levels can further differentiate mesothelioma effusions from other malignant and benign effusions. (Funded by the Early Detection Research Network, National Institutes of Health, and others.).

Clinical presentation of asbestosis with intractable pleural pain in the adult child of a taconite miner and radiographic demonstration of the probable pathology causing the pain

Taconite, although not classified by the United States Government as asbestos or asbestiform material, has been associated with asbestos-related diseases. The mineral is used in the production of steel and as a road-patch material and is mined in Michigan and Minnesota. This report describes the case of a middle-aged Caucasian woman with exposure to taconite mining dust from her miner father's clothing in childhood with a resultant presentation consistent with asbestosis and intractable pleural pain. Intractable pleural pain has been described in asbestos-exposed patients with theorized etiologies. However, no in vivo reported mechanism has demonstrated a plausible, anatomically apparent mechanism for the pain. We utilize an application of the Vitrea software for enhancement of high-resolution computerized tomography which demonstrates at least one likely mechanism for intractable pleural pain.

Respiratory health in asbestos-exposed ironworkers

This study aimed to determine the prevalence of respiratory morbidity among asbestos-exposed ironworkers and to determine the relationship between respiratory morbidity indices and length of exposure. A medical screening provided information on chest radiographic abnormalities, pulmonary function, rales, finger clubbing, and respiratory symptoms for 547 asbestos-exposed ironworkers. Union pension records furnished data on length of exposure. The study group exhibited on increased prevalence of small irregular opacities, pleural plaques, and pleural thickening on chest x-ray; reduced FEF 25-75; rales; and respiratory symptoms. After controlling for the effect of cigarette smoking and age, years since joining the ironworkers union were significantly associated with profusion, pleural thickening, pleural plaques, rales, percent predicted FVC, reduced FVC, reduced FEV1, reduced FEV1/FVC, and dyspnea grades I, II, III, and IV.