Marker For Malignant Pleural Mesothelioma Research Articles

PD-1-expressing macrophages and CD8 T cells are independent predictors of clinical benefit from PD-1 inhibition in advanced mesothelioma

BackgroundFew tissue biomarkers exist to date that could enrich patient with cancer populations to benefit from immune checkpoint blockade by programmed cell death protein 1/ligand-1 (PD-/L-1) inhibitors. PD-L1 expression has...

11P Association of VISTA-expressing CD66b-positive neutrophils, with response and survival benefit from pembrolizumab in advanced malignant pleural mesothelioma

V-domain Ig suppressor of T cell activation, VISTA, is a type I transmembrane protein that functions as an immune checkpoint. VISTA can be expressed by a wide range of cell types. Malignant pleural mesothelioma (MPM) is a tumor type with the highest levels of VISTA expression. However, it remains unclear if VISTA could be a predictive or prognostic marker in MPM following PD-1 blockade.

Identification of glycolysis genes signature for predicting prognosis in malignant pleural mesothelioma by bioinformatics and machine learning.

Glycolysis-related genes as prognostic markers in malignant pleural mesothelioma (MPM) is still unclear. We hope to explore the relationship between glycolytic pathway genes and MPM prognosis by constructing prognostic risk models through bioinformatics and machine learning. The authors screened the dataset GSE51024 from the GEO database for Gene set enrichment analysis (GSEA), and performed differentially expressed genes (DEGs) of glycolytic pathway gene sets. Then, Cox regression analysis was used to identify prognosis-associated glycolytic genes and establish a risk model. Further, the validity of the risk model was evaluated using the dataset GSE67487 in GEO database, and finally, a specimen classification model was constructed by support vector machine (SVM) and random forest (RF) to further screen prognostic genes. By DEGs, five glycolysis-related pathway gene sets (17 glycolytic genes) were identified to be highly expressed in MPM tumor tissues. Also 11 genes associated with MPM prognosis were identified in TCGA-MPM patients, and 6 (COL5A1, ALDH2, KIF20A, ADH1B, SDC1, VCAN) of them were included by Multi-factor COX analysis to construct a prognostic risk model for MPM patients, with Area under the ROC curve (AUC) was 0.830. Further, dataset GSE67487 also confirmed the validity of the risk model, with a significant difference in overall survival (OS) between the low-risk and high-risk groups (P < 0.05). The final machine learning screened the five prognostic genes with the highest risk of MPM, in order of importance, were ALDH2, KIF20A, COL5A1, ADH1B and SDC1. A risk model based on six glycolytic genes (ALDH2, KIF20A, COL5A1, ADH1B, SDC1, VCAN) can effectively predict the prognosis of MPM patients.

KIAA0101 in Malignant Pleural Mesothelioma: A Potential Diagnostic and Prognostic Marker.

Currently, there are no reliable diagnostic and prognostic markers for Malignant Pleural Mesothelioma (MPM). The objective of this study was to identify hub genes that could be helpful for diagnosis and prognosis in MPM by using bioinformatics analysis. The gene expression profiles were downloaded from the Gene Expression Omnibus (GEO) database and The Cancer Genome Atlas (TCGA). Weighted Gene Co-expression Network Analysis (WGCNA), LASSO regression analysis, Cox regression analysis, and Gene Set Enrichment Analysis (GSEA) were performed to identify hub genes and their functions. A total of 430 upregulated and 867 downregulated genes in MPM were identified based on the GSE51024 dataset. According to the WGCNA analysis, differentially expressed genes were classified into 8 modules. Among them, the pink module was most closely associated with MPM. According to genes with GS > 0.8 and MM > 0.8, six genes were selected as candidate hub genes (NUSAP1, TOP2A, PLOD2, BUB1B, UHRF1, KIAA0101) in the pink module. In the LASSO model, three genes (NUSAP1, PLOD2, and KIAA0101) were identified with non-zero regression coefficients and were considered as hub genes among the 6 candidates. The hub gene-based LASSO model can accurately distinguish MPM from controls (AUC=0.98). Moreover, the high expression level of KIAA0101, PLOD2, and NUSAP1 was associated with poor prognosis compared to the low level in Kaplan-Meier survival analyses. After further multivariate Cox analysis, only KIAA0101 (HR = 1.55, 95% CI = 1.05-2.29) was identified as an independent prognostic factor among these hub genes. Finally, GSEA revealed that high expression of KIAA0101 was closely associated with 10 signaling pathways. Our study identified several hub genes relevant to MPM, including NUSAP1, PLOD2, and KIAA0101. Among these genes, KIAA0101 appears to be a useful diagnostic and prognostic biomarker for MPM, which may provide new clues for MPM diagnosis and therapy.

PD-L1, VISTA, and CD47 expression and prognosis impact in malignant pleural mesothelioma.

8562 Background: Malignant Pleural Mesothelioma (MPM) has been characterized by an immune suppressive microenvironment. The immune checkpoint (IC) VISTA is notably expressed in MPM, in contrast to other IC proteins such us PD-L1. Recently, CD47 has been described as a possible diagnostic biomarker for MPM, although its impact in prognosis has not been established yet. Methods: This is a retrospective observational study of immunotherapy naïve MPM patients. Immunochemistry (IHC) assessment of PD-L1, VISTA and CD47 protein expression was performed on tissue microarray of 46 surgical samples. Means were compared using Mann-Whitney U test. Correlation was estimated using Pearson’s coefficients. Overall survival (OS) was assessed using Kaplan–Meier curves and Cox proportional hazard models. A two-sided alpha error of 0.05 was used to assess statistical significance. Statistical analysis was conducted with Stata/SE version 16.1. Results: A total of 46 patients, 71.7% (33/46) male, were included in our study. Among them, 77.8% (35/45) had stage IIIB-IV, 84.8% (39/46) had received systemic therapy and 16.7% (7/42) had undergone radical-intent surgery. Asbestos exposure was confirmed in 65,7% (23/35) patients. Regarding the histological subtype, 71.7% (33/46) were epithelioid (Ep) and 13.0% (6/46) non-epithelioid (NEp), including 5 sarcomatoid and 1 biphasic. In IHC analysis, VISTA and CD47 were expressed in 63.0% (29/46) and 58.7% (27/46), respectively, whereas only 28.3% (13/46) patients had positive PD-L1 expression (≥1%). Median expression of VISTA, CD47 and PD-L1 in tumor samples was 41.8 (95% IC 0.5 - 50.7), 26.3 (95% IC 0 - 45.8) and 0 (95% IC 0-0.5), respectively. VISTA and CD47 expression were significantly higher in the Ep subgroup vs. the NEp subgroup (VISTA 39.4% vs 7.2% p = 0.028; CD47 37.3 vs. 0.8 p = 0.01). Additionally, we found a significant positive correlation between VISTA and CD47 protein expression (Pearson's r = 0.55, p &lt; 0.001), which was consistent with the results we found in an independent MPM patient series from TCGA PanCancer Atlas (N = 87) based on RNA expression (r = 0.46; p &lt; 0.001). Median OS, available in 40/46 cases, was 16.6 months (95% CI 12.03-20.43). On multivariate analysis, CD47 ≥1% expression was significantly associated with longer OS (29.7 vs 10.53 months, HR 0.35, [IC 95% 0.14-0.86]; p = 0.02) after adjusting for histological subtype, PDL1 and VISTA expression. In contrast, PD-L1 ≥1% showed a trend towards worse prognosis (10.3 vs 19.3 months), without reaching statistical significance (HR 2.23 [95% IC 0.95-5.23]; p = 0.065). No OS differences were found regarding VISTA expression. Conclusions: To our knowledge, this is the first study to describe VISTA and CD47 correlation in MPM. Moreover, we demonstrate CD47 expression to be an independent prognostic marker in MPM, suggesting C47 may play a key role in tumor biology of MPM, for which further validation and functional studies are necessary.

Sulfated Glycans Recognized by S1 Monoclonal Antibody can Serve as a Diagnostic Marker for Malignant Pleural Mesothelioma.

Malignant pleural mesothelioma (MPM) is a malignant neoplasm of the pleura caused by asbestos exposure. For diagnosis of MPM, immunohistochemistry using multiple markers is recommended to rule out differential diagnoses, such as pulmonary adenocarcinoma. However, the specificity of currently used markers is not fully satisfactory. We previously developed a monoclonal antibody named S1, which recognizes 6-sulfo sialyl Lewis x, an L-selectin ligand expressed on high endothelial venules. During the screening process, we discovered that this antibody stained normal pleural mesothelium. This finding prompted us to hypothesize that the epitope recognized by S1 might serve as a new diagnostic marker for MPM. To test this hypothesis, we immunostained human MPM (n = 22) and lung adenocarcinoma (n = 25) tissues using S1 antibody. 77.3% of MPM were S1 positive, and if limited to epithelioid type, the positivity rate was 100%, while that of lung adenocarcinoma was only 36.0%. Statistical analysis revealed a significant difference in the S1 positivity rate between each disease. Furthermore, immunohistochemistry using a series of anti-carbohydrate antibodies combined with glycosidase digestion revealed the structure of sulfated glycans expressed in MPM to be 6-sulfo sialyl N-acetyllactosamine attached to core 2-branched O-glycans. We propose that the S1 glycoepitope could serve as a new diagnostic marker for MPM.

Identification of Novel Diagnostic Markers for Malignant Pleural Mesothelioma Using a Reverse Translational Approach Based on a Rare Synchronous Tumor.

Although the routine use of immunohistochemistry has improved the accuracy of histopathologic diagnosis in clinical practice, new methods for discovering novel diagnostic markers are still needed. We sought new diagnostic markers for malignant pleural mesothelioma (MPM) using a reverse translational approach with limited archival tissues from a very rare case. Total RNA extracted from formalin-fixed paraffin-embedded (FFPE) tissues of a synchronous collision tumor consisting of MPM and pulmonary adenocarcinoma (PAC) was employed for gene expression profiling (GEP) analysis. Among the 54 genes selected by GEP analysis, we finally identified the following two candidate MPM marker genes: PHGDH and TRIM29. Immunohistochemical analysis of 48 MM and 20 PAC cases showed that both PHGDH and TRIM29 had sensitivity and specificity almost equivalent to those of calretinin (sensitivity 50% and 46% vs. 63%, and specificity 95% and 100% vs. 100%, respectively). Importantly, of the 23 epithelioid MMs, all 3 calretinin-negative cases were positive for TRIM29. These two markers may be diagnostically useful for immunohistochemical distinction between MPMs and PACs. This successful reverse translational approach based on FFPE samples from one very rare case encourages the further use of such samples for the development of novel diagnostic markers.

Pleural mesothelioma: research of mechanisms involved in carcinogenesis. The role of CD10

The present study was conducted at Surgical Pathology Department of “Santo Spirito” hospital in Casale Monferrato (AL) and in collaboration with the Cellular Biology and Physiology laboratory located in the institution of DiSIT-Università del Piemonte Orientale. In the pathology facility a retrospective analysis on the immunohistochemical expression of CD10 marker in malignant pleural mesothelioma was delineated. For this purpose it was collected a sample of 63 pleural biopsies with a diagnosis of pleural mesothelioma come in the period of January 2015 and November 2020. In this cohort, CD10 expression was assessed from a prognostic perspective and in relation to morphologic aspects of the neoplasm. Results from previous analysis built the basis of the experiment conducted in the DiSIT facility. Two pleural mesothelioma cell lines, REN and MM98, got incubated with the cytokine TGF-β aiming to analyze the potential relationship between epithelial-to-mesenchymal transition (EMT) and CD10 cell expression pattern. Bioinformatic server Haddock 2.4 helped to predict and model potential cross-talk between EMT underlying pathways and CD10 signalling. Objectives: The present study aimed to assess prognostic role of CD10 immunohistochemical expression in a cohort of patients affected by pleural mesothelioma. Second goal was to analyze the relationship between CD10 biopsy expression, phenotypical and imunophenotypical features (referring in particular to PDL-1 expression) of the neoplasm. Results from this retrospective analysis established next aim of the study: induction of EMT in two mesothelioma cell lines, REN and MM98, and analysis of change in CD10 cellular pattern. Final goal was to predict a potential cross-talk between EMT related pathways and CD10 activity based on bioinformatic server Haddock 2.4.Methods: Immunohistochemical analysis of biopsies and cell cultures were processed on Ventana Benchmark immunostainer. Tools adopted in qRT-PCR of cell cultures were: Power Sybr Green Mastermix probes (Ambion Austin, TX, USA) and KiCqStart® SYBR® Green primers (Sigma-Aldrich); Real-Time PCR CFX384 detection system (Bio-Rad Laboratories, Hercules, CA, USA). Gene expressione was measured with ∆∆Ct method. Parametrization of CD10 immunohistochemical expression was accomplished with cell imaging software CellProfiler 3.1.9. Statistical analysis were ran with R software version 3.6.2. Results: CD10 showed to be a negative prognostic factor, positively associated to neoplastic grade, in the cohort of patients analyzed. Induction of EMT in REN and MM98 TGF-β treated cultures, augmented CD10 cytosolic expression against non-treated cultures. Specifically, a change in CD10 immunoexpression pattern, from membranous to cytosolic, was observed for EMT+ REN cell culture. This data agrees with prevalent CD10 cytosolic expression observed in mesothelioma with low differentiation, where differentiation represents a function of EMT. Furthermore, Haddock data highlighted a potential promotion of EMT by CD10 via a NF-kB interaction. CD10 could establish a positive feedback loop with EMT. Conclusion: CD10 represents a positive marker of neoplastic progression in pleural mesothelioma that, based on its expression level, can stratify survival. Experimental data showed that CD10 could be upregulated by EMT pathways. Bionformatic analysis also suggest that CD10 could interact with EMT establishing a positive feedback loop. Clarifying tumorigenicity of CD10 in mesothelioma is fundamental to define its possible therapeutic role.

CLDN15 is a novel diagnostic marker for malignant pleural mesothelioma

Malignant mesothelioma is a cancer with a poor survival rate. It is difficult to diagnose mesotheliomas because they show a variety of histological patterns similar to those of various other cancers. However, since currently used positive markers for mesotheliomas may show false positives or false negatives, a novel mesothelial positive marker is required. In the present study, we screened 25 claudins and found that claudin-15 is expressed in the mesothelial cells. We made new rat anti-human claudin-15 (CLDN15) monoclonal antibodies that selectively recognize CLDN15, and investigated whether CLDN15 is a good positive marker for malignant pleural mesotheliomas (MPMs) using MPM tissue samples by immunohistochemistry and semi-quantification of the expression level using an immunoreactive score (IRS) method. Of 42 MPM samples, 83% were positive for CLDN15. The positive ratio was equal to or greater than other positive markers for MPMs including calretinin (81%), WT-1 (50%), and D2-40 (81%). In 50 lung adenocarcinoma sections, four cases were positive for CLDN15 and the specificity (92%) was comparable with other markers (90–100%). Notably, CLDN15 was rarely detected in 24 non-mesothelial tumors in the tissue microarray (12/327 cases). In conclusion, CLDN15 can be used in the clinical setting as a positive marker for MPM diagnosis.

Combined Analysis of RNA Sequence and Microarray Data Reveals a Competing Endogenous RNA Network as Novel Prognostic Markers in Malignant Pleural Mesothelioma.

Malignant pleural mesothelioma (MPM) is a highly aggressive cancer with short survival time. Unbalanced competing endogenous RNAs (ceRNAs) have been shown to participate in the tumor pathogenesis and served as biomarkers for the clinical prognosis. However, the comprehensive analyses of the ceRNA network in the prognosis of MPM are still rarely reported. In this study, we obtained the transcriptome data of the MPM and the normal samples from TCGA, EGA, and GEO databases and identified the differentially expressed (DE) mRNAs, lncRNAs, and miRNAs. The functions of the prognostic genes and the overlapped DEmRNAs were further annotated by the multiple enrichment analyses. Then, the targeting relationships among lncRNA–miRNA and miRNA–mRNA were predicted and calculated, and a prognostic ceRNA regulatory network was established. We included the prognostic 73 mRNAs and 13 miRNAs and 26 lncRNAs into the ceRNA network. Moreover, 33 mRNAs, three miRNAs, and seven lncRNAs were finally associated with prognosis, and a model including seven mRNAs, two lincRNAs, and some clinical factors was finally established and validated by two independent cohorts, where CDK6 and SGMS1-AS1 were significant to be independent prognostic factors. In addition, the identified co-expressed modules associated with the prognosis were overrepresented in the ceRNA network. Multiple enrichment analyses showed the important roles of the extracellular matrix components and cell division dysfunction in the invasion of MPM potentially. In summary, the prognostic ceRNA network of MPM was established and analyzed for the first time and these findings shed light on the function of ceRNAs and revealed the potential prognostic and therapeutic biomarkers of MPM.

P1.06-12 Defects in Homologous Recombination Repair Indicates Susceptibility for Olaparib Treatment in Malignant Pleural Mesothelioma

Malignant pleural mesothelioma (MPM) is a tumour with dismal prognosis. Chemotherapeutic treatment with pemetrexed combined with cisplatin shows unsatisfying response-rates of 40%. The reasons for the rather poor efficacy remain largely unknown. However, it is conceivable that DNA repair mechanisms lead to an impaired therapy response. We hypothesize a major role of homologous recombination (HR) for genome stability and survival of this tumour. Therefore, we analysed expression levels of genes compiled under the term “BRCAness”. An inhibition of this pathway with olaparib might abrogate this effect and induce apoptosis. We evaluated the response of three MPM cell lines and lung fibroblasts, serving as a control to treatment, with pemetrexed, cisplatin and olaparib. Furthermore, we aimed to find correlations between response and gene expression patterns associated with BRCAness phenotype. Therefore, 91 clinical MPM samples were digitally screened for gene expression patterns of HR members. We observed a BRCAness-dependent increase of apoptosis and senescence during olaparib-based treatment of BRCA-associated-protein 1 (BAP1)-mutated cell lines. The gene expression pattern identified could be found in approx. 10% of patient samples. Against this background, patients could be grouped according to their defects in the HR system. Gene expression levels of Aurora Kinase A (AURKA), RAD50 as well as DNA damage-binding protein 2 (DDB2) could be identified as prognostic markers in MPM. Defects in HR compiled under the term BRCAness are a common event in MPM. The present data may improve the understanding of underlaying cellular mechanisms and open new possibilities for modern therapeutic approaches for this severe disease. Response to Poly (ADP-ribose)-Polymerase (PARP)-Inhibition could be demonstrated in the BAP1-mutated NCI-H2452 cells, especially when combined with cisplatin. This combination therapy might be effective for up to 2/3 of patients, promising to enhance patients’ clinical management and outcome.

Abstract 1349: Personalized circulating tumor DNA profiling in malignant pleural mesothelioma

Abstract Background: Malignant pleural mesothelioma (MPM) is an aggressive tumor associated with exposure to asbestos and is rising in incidence worldwide. A lack of early detection methods and treatment successes have maintained a dismal prognosis of just 12 - 16 months. Circulating tumor DNA (ctDNA) is emerging as an important stratification biomarker in other thoracic malignancies, however research in this area has been lacking in MPM. Homozygous deletion of CDKN2A is one of the few established negatively prognostic molecular markers in MPM. Methods and Results: We conducted multiregional whole exome sequencing (m-WES) on tumor tissue (4 or 5 regions) and matched germline DNA from 11 patients with MPM that received surgery (extended pleurectomy decortication) as their primary treatment modality. Using a validated bioinformatics pipeline (developed as part of the TRACERx study), clonal single nucleotide variants (SNVs) and/or indels (present within all tumor regions) were selected from m-WES data for patient-specific assay design. Variants were prioritized for selection based on tumor driver status and higher mean variant allele frequencies (VAFs) amongst tumor regions. A minimum of 10 ng cfDNA isolated from pre-surgical blood was analyzed for ctDNA detection using Droplet Digital PCR (ddPCR), with positivity being defined as ≥ 3 mutant droplets and a plasma VAF ≥ 0.1%. Four out of eleven (36.4%) patients were ctDNA-positive using this patient-specific approach with VAFs ranging between 0.16% and 2.96%. Two additional patients had one or two positive mutant droplets, but these were excluded as potential false positives. In this pilot study, ctDNA-positive patients had significantly shorter survival than ctDNA-negative patients (P = 0.047), although this failed to reach significance by Cox regression analysis, likely due to a small sample size. Furthermore, in this cohort ctDNA status was a stronger prognostic biomarker than CDKN2A deletion status. Conclusions: Considering the short survival of patients with MPM despite surgery, we consider ctDNA-based analyses could be used to stratify patients regarding surgery, where risk-benefit would be marginal for those ctDNA-positive. This study provides proof-of-principle that the detection of tumor DNA from minimally invasive sources is possible in MPM and has alluded to how this could potentially impact clinical decision-making. Citation Format: Luke J. Martinson, Annabel J. Sharkey, Alan G. Dawson, Robert K. Hastings, Gareth Wilson, David Waller, Apostolos Nakas, Charles Swanton, Jacqui A. Shaw, Dean A. Fennell. Personalized circulating tumor DNA profiling in malignant pleural mesothelioma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1349.

MiR-21 over-expression and Programmed Cell Death 4 down-regulation features malignant pleural mesothelioma

BackgroundDifferential diagnosis between malignant pleural mesothelioma (MPM) and benign mesothelial conditions is still challenging and there is a lack of useful markers. Programmed cell death 4 (PDCD4) is a well-known tumor suppressor gene in several cancers, its post-transcriptional activity is directly controlled by miR-21, whose over-expression has been recently reported in MPM compared to normal mesothelium. Aim of this study was to test this suppressor gene as a possible new marker of malignant transformation in mesothelial cells, as well as a new prognostic marker.MethodsPDCD4 nuclear expression was assessed by immunohistochemistry (IHC) in 40 non-neoplastic pleural (NNP) and 40 MPM formalin-fixed and paraffin-embedded specimens. PDCD4 and miR-21 expressions were analyzed by qRT-PCR in all cases. In situ hybridization (ISH) of miR-21 was performed in 5 representative cases of both groups. The prognostic relevance of PDCD4 was assessed in a public available gene expression dataset.ResultsIHC showed that PDCD4 nuclear expression was significantly lower in MPM than in NNP. PDCD4 was down-regulated, whereas miR-21 was over-expressed in MPM cases compared to NNP ones. ISH detected miR-21 only in MPM specimens. Down-expression of PDCD4 was found significantly associated with short overall survival in publicly available data.ConclusionsThese findings highlighted a switch between PDCD4 and miR-21 expression in MPM. Further studies should assess the diagnostic reliability of these two markers for MPM in biopsy and effusion specimens.

Posttranscriptional Regulation Controls Calretinin Expression in Malignant Pleural Mesothelioma

Calretinin (CALB2) is a diagnostic and prognostic marker in malignant pleural mesothelioma (MPM). We previously reported that calretinin expression is regulated at the mRNA level. The presence of a medium-sized (573 nucleotide) 3′ untranslated region (3′UTR) predicted to contain binding sites for miR-30a/b/c/d/e and miR-9 as well as an adenine/uridine-rich element (ARE) in all three transcripts arising from the CALB2 gene, suggests that calretinin expression is regulated via posttranscriptional mechanisms. Our aim was to investigate the role of the CALB2-3′UTR in the posttranscriptional regulation of calretinin expression in MPM. CALB2-3′UTR was inserted downstream of the luciferase reporter gene using pmiRGLO vector and reporter expression was determined after transfection into MPM cells. Targeted mutagenesis was used to generate variants harboring mutated miR-30 family and ARE binding sites. Electrophoretic mobility shift assay was used to test for the presence of ARE binding proteins. CALB2-3′UTR significantly decreased luciferase activity in MPM cells. Analysis of mutation in the ARE site revealed a further destabilization of the reporter and human antigen R (HuR) binding to the ARE sequence was detected. The mutation of two miR-30 binding sites abolished CALB2-3′UTR destabilization effect; a transient delivery of miR-30e-5p mimics or anti-miR into MPM cells resulted in a significant decrease/increase of the luciferase reporter expression and calretinin protein, respectively. Moreover, overexpression of CALB2-3′UTR quenched the effect of miR-30e-5p mimics on calretinin protein levels, possibly by sequestering the mimics, thereby suggesting a competitive endogenous RNA network. Finally, by data mining we observed that expression of miR-30e-5p was negatively correlated with the calretinin expression in a cohort of MPM patient samples. Our data show the role of (1) adenine-uridine (AU)-binding proteins in calretinin stabilization and (2) miR-30e-5p in the posttranscriptional negative regulation of calretinin expression via interaction with its 3′UTR. Furthermore, our study demonstrates a possible physiological role of calretinin’s alternatively spliced transcripts.

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

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&amp;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.

P3.03-047 Diagnostic Value of Secretary Leukocyte Peptide Inhibitor (SLPI) in Pleural Fluid in Malignant Pleural Mesothelioma: Topic: Mesothelioma Clinical

There is no established diagnostic marker for malignant pleural mesothelioma (MPM). The aim of this study was to evaluate the usefulness of secretary leukocyte peptide inhibitor (SLPI) in pleural fluid for the diagnosis of MPM. The study included 52 MPM patients, 69 patients of lung cancer with pleural effusion (LC), and 50 patients with benign asbestos pleural effusion (BAPE) that were included as a control group. Pleural fluid was collected from these patients and SLPI was determined using Quantikine ELISA Human SLPI (R＆D Systems). Pleural fluid hyaluronic acid (HA) and soluble mesothelin related peptide (SMRP) were also determined as comparison. Median values of pleural fluid SLPI in MPM, LC, and BAPE were 108.1 ng/ml, 87.4 ng/ml, and 48.6 ng/ml, respectively. SLPI value in patients with MPM were significantly higher than those in other groups (P=0.000). SLPI value was higher in epithelioid subtype of MPM than in other subtypes. Median values of pleural fluid HA in MPM, LC, and BAPE were 86950 ng/ml, 20700 ng/ml, and 31500 ng/ml, respectively. Median values of pleural fluid SMRP in MPM, LC, and BAPE were 15.38 ng/ml, 5.70 ng/ml, and 7.31 ng/ml, respectively. Pleural fluid HA and SMRP in MPM were also significantly higher than in other groups (P=0.000). Receiver operating characteristics analysis was performed to examine the usefulness of these 3 markers for the differentiation of MPM and BAPE, and demonstrated that area under the curve values were 0.823 for SLPI, 0.760 for HA, and 0.743 for SMRP. Pleural fluid SLPI is a useful biomarker for differential diagnosis of MPM.

Molecular markers for malignant pleural mesothelioma in Mexico

Introduction: Malignant pleural mesothelioma (MPM) is a lethal cancer. There is an epidemic of MPM in Mexico with 500 cases per year. The diagnosis remains a challenge, so it is relevant to develop inexpensive and less invasive diagnostic tests. Methods: Case-control study from 3 different hospitals; MPM cases were confirmed by immunohistochemistry and histopathology. Asbestos exposure was assessed using a clinical and occupational questionnaire. Biomarkers levels were measured using ELISA. Based on ROC curves and the highest sensitivity, cut-off points were established for each biomarker. A logistic regression model was built to obtain odds ratios (OR) and 95% confidence intervals for each biomarker. Results: 101 MPM cases and 457 controls were included. Biomarkers mean levels were statistically different between cases and controls and between sexes. Area under the curve (AUC), sensitivity and cut-off points were determined: mesothelin 0.91, 90.9% and 1.59 nmol/l; calretinin 0.85, 94% and 0.69 nmol/l; and thrombomodulin 0.56, 55.8% and 0.68 nmol/l. In the logistic model for both sexes, based on cut-off points, the OR were: mesothelin &gt;0,74 nmol/l: OR=13.5 (5.7-33.5); calretinin &gt;0.23 ng/ml: OR=10 (4.6-21.7); thrombomodulin was discarded from the model. Models weighted by sex showed differences between men and women in calretinin levels, which showed a poor performance in women. Conclusions: Mesothelin and calretinin showed a good performance in men. Cut-off points support the diagnostic accuracy differentiated by sex in MPM cases. Cut-off points and biomarkers levels should be analyzed separately by sex.

Prognostic value of the lymphocyte-to-monocyte ratio and other inflammatory markers in malignant pleural mesothelioma.

Inflammation plays a role in malignant pleural mesothelioma (MPM) prognosis and symptoms. We investigated the roles of the new and old inflammatory indexes and markers in MPM prognosis. Two hundred and ninety-two MPM patients (167 male and 125 female) were included in this retrospective study. Demographic parameters were collected from the patients' files. Kaplan-Meier curves and multivariate Cox regression analyses were used for the analysis of prognosis. The mean age of the patients was 58.4years. The mean survival time was 14.6±13.0months. Twenty-four potential prognostic factors associated with a poor outcome were calculated in the univariate analysis, and 16 potential prognostic factors were associated with a poor prognosis. These 16 potential prognostic factors were also analyzed in multivariate analysis. Multivariate analysis showed that increased age, stage 3-4 disease, the non-epithelial type, a low Karnofsky performance score, a high white blood cell count, and a low lymphocyte-to-monocyte ratio (LMR) were associated with a poor prognosis. The results of the multivariate analysis showed that a decreased LMR was associated with poor survival. Patients with LMR ≤2.6 had poor survival compared with those with LMR >2.6 (mean 9.6 vs. 17.0months, respectively; p=0.004). LMR is an independent marker of prognosis in patients with MPM and is superior to the other inflammation-based markers. The inexpensive nature and easy reproducibility of the hemogram should encourage the use of the LMR in clinical practice.

Clinical utility of diagnostic markers for malignant pleural mesothelioma

Malignant mesothelioma has a very dismal prognosis with very few patients surviving one year after diagnosis. Early multimodal treatment, however, is expected to improve the outcome. Today, there is a strong need to have disease markers which could be used for screening, diagnosing, and/or monitoring tumour response to treatment. Old markers such as hyaluronic acid, various cytokeratin fragments (CYFRA 21.1, TPA) and other cancer antigens (CA 15.3, CA 125 or CA 19.9 or CEA) are not sensitive or specific enough and cannot be used in practice. More recently new molecules, such as soluble mesothelin and osteopontin, have been proposed for diagnostic purposes. Soluble mesothelin has a good specificity but has a sub-optimal sensitivity being negative in all sarcomatoid and in up to one half of epithelioid mesothelioma. On the contrary osteopontin has an inadequate specificity. Combining different markers together does not lead to an improvement in diagnostic accuracy. Neither marker can be used for screening purposes, the main limitation being the very low incidence of the disease in the at-risk, asbestos exposed population. Mesothelin is also a promising marker for monitoring response to treatment but published data is still insufficient to make recommendations. There is still a strong need for research is this area both in order to discover new markers as well as to correct the positioning of each existing molecule (alone or in combination) is the evaluation of the patients with a mesothelioma.

Abstract 4338: Clinical significance of soluble CD26 in malignant pleural mesothelioma

Abstract There is no established diagnostic marker for malignant pleural mesothelioma (MPM). CD26 is a 110 kDa, multifunctional, membrane-bound glycoprotein on the surface of many cell types that has dipeptidyl peptidase IV (DPPIV) enzyme activity. The aim of this study was to evaluate the clinical significance of soluble CD26 in patients with MPM. The study included 80 MPM patients, 79 subjects with past asbestos exposure (SPE), and 134 patients with other benign pleural diseases (OPD) that were included as a control group. Soluble CD26 levels and DPPIV activity in serum and/or pleural fluid were determined using an ELISA kit. Serum sCD26 levels and DPPIV enzyme activity in patients with MPM were significantly decreased compared with those in the SPE group (P = 0.000). The level of serum sCD26 was significantly decreased in patients with advanced stages of MPM compared with those with earlier stages (P = 0.047). The median OS of patients with MPM who had higher DPPIV enzyme activity was significantly longer than that of those with lower DPPIV enzyme activity (P = 0.032). The sCD26 levels in the pleural fluid of MPM patients with an epithelioid subtype were significantly increased compared with the OPD cohort (P = 0.012). Moreover, DPPIV enzyme activity in the pleural fluid of patients with MPM with an epithelioid subtype were significantly increased compared with those in the OPD cohort (P = 0.009). Patients with MPM who had lower specific DPPIV activity, determined as DPPIV/sCD26, showed significantly prolonged survival compared with those with higher specific DPPIV activity (P = 0.028). Serum sCD26 and DPPIV enzyme activity appear to be useful biomarkers for differentiating patients with MPM from SPE. The sCD26 levels or DPPIV enzyme activity in pleural fluid appear to be biomarkers in patients with an epithelioid subtype of MPM. DPPIV activity in serum or pleural fluid appears to be predictive for the prognosis of patients with MPM. Citation Format: Nobukazu Fujimoto, Kei Ohnuma, Keisuke Aoe, Osamu Hosono, Taketo Yamada, Takumi Kishimoto, Chikao Morimoto. Clinical significance of soluble CD26 in malignant pleural mesothelioma. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4338. doi:10.1158/1538-7445.AM2015-4338