Evaluation of Soluble Mesothelin-related Peptide as a Diagnostic Marker of Malignant Pleural Mesothelioma Effusions: Its Contribution to Cytology

e17533 Background: Detection of soluble mesothelin-related peptide (SMRP) levels in serum has been proposed to help the diagnosis of malignant pleural mesothelioma (MPM). In this study we evaluated the SMRP levels in pleural effusions of MPM (MPM-PE), the clinical importance and usefulness of SMRP detection in MPM-PE and whether it can have an additional value to cytological analysis (Cyt). Methods: We studied 52 MPM-PE, 129 benign PE (B-PE) and 94 non-MPM pleural metastasis PE (Mts-PE). In all PE samples, both cytology and SMRP detection were performed. SMRP levels were estimated by means of the MesoMark ELISA kit (Fujirebio Diagnostic, Malvern, PA). Diagnostic performance parameters were estimated through the ROC analysis, Youden's index was applied to obtain the best cut-off level and the degree of correlation was estimated by Diagnostic Odds Ratio (DOR) and by P-value (P) with Chi-square test. Results: The median SMRP levels were significantly higher in MPM-PE (28.2 nM) than in B-PE (3.2 nM) or Mts-PE (3.8 nM). MPM-PE vs B-PE yielded an AUC of 84.5 (P<0.001) whereas MPM-PE vs Mts-PE yelded an AUC of 79.6 (P<0.001). The cut off level in MPM-PE was estimated in 9.30 nM at which value we established Se=75%, Sp=93% for MPM-PE vs BPE and SP=81% for MPM-PE vs Mts-PE. We found SMRP positive cases (≥ cut off) in 38/52 (73%) MPM-PE, in 9/129 (7%) B-PE (DOR=40, P<0.001) and in 18/94 (19%) Mts-PE (DOR=13, P< 0.001).Cyt was negative in 29/52 (56%) of MPM-PE, among which SMRP was positive in 20/29 (69%) cases. Cyt was positive in 15/52 (29%) of MPM-PE, among which SMRP was negative in 4/15 (27%) cases. Finally, in 8/52 (15%) MPM-PE Cyt diagnosis was suspicious and SMRP was found positive in 7/8 (88%) cases. Conclusions: Our results demonstrate that SMRP levels in PE are significantly higher in MPM-PE than in PE from other pathologies. However the test cannot be alternative to cyt but it may provide additional diagnostic value to Cyt. SMRP detection in MPM-PE can be applied in the workup of patients with a PE of unknown origin.

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Secretary leukocyte peptide inhibitor (SLPI) in pleural fluid is useful as a diagnostic marker of malignant pleural mesothelioma.

Journal of Clinical Oncology ◽

10.1200/jco.2017.35.15_suppl.e23098 ◽

2017 ◽

Vol 35 (15_suppl) ◽

pp. e23098-e23098

Author(s):

Nobukazu Fujimoto ◽

Yoko Kojima ◽

Takumi Kishimoto

Keyword(s):

Pleural Fluid ◽

Malignant Pleural Mesothelioma ◽

Roc Analysis ◽

Diagnostic Marker ◽

Area Under The Curve ◽

Peptide Inhibitor ◽

Pleural Mesothelioma ◽

Exploratory Research ◽

Operating Characteristics ◽

Auc Value

e23098 Background: There is no established diagnostic marker for malignant pleural mesothelioma (MPM). In particular, the differentiation from benign asbestos pleural effusion (BAPE) is challenging. Secretary leukocyte peptide inhibitor (SLPI) is an enzyme encoded by SLPI gene. SLPI gene is reported to be overexpressed in MPM cells. Methods: SLPI in pleural fluid was determined using Quantikine ELISA Human SLPI kit (R&D Systems). Results: Exploratory research revealed that SLPI value in pleural fluid of patients with MPM (n = 52) were significantly higher than those in lung cancer (LC) (n = 69) and BAPE (n = 50) ( P= 0.000). Prospective validation study included 12 pts of MPM, 24 pts of LC, 26 pts of BAPE. Median values of SLPI in MPM, LC, and BAPE were 159 .6 ng/ml, 90.5 ng/ml, and 43.2 ng/ml, respectively. SLPI value in patients with MPM were significantly higher than those in other groups ( P= 0.000). Receiver operating characteristics ROC) analysis was performed to examine the usefulness of differentiation of MPM and other diseases, and demonstrated that area under the curve (AUC) value was 0.758. With the cut of value of 88.6 ng/ml, the sensitivity was 83.3% and the specificity was 59.8%. Concerning the differentiation between MPM and BAPE, AUC value was 0.904 and with the cut of value of 81.8 ng/ml, the sensitivity was 83.3% and the specificity was 92.3%. Conclusions: Pleural fluid SLPI is a useful biomarker for the diagnosis of MPM, in particular, for the differentiation from BAPE.

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