Serum Mesothelin Research Articles

Emerging Role of Immunomonitoring to Predict the Clinical Outcome of Patients With Malignant Pleural Mesothelioma Treated With Radical Radiation Therapy

The present study aimed at evaluating the baseline immune profile and the immunomodulating effects of radical hemithoracic radiation therapy (RT) in patients affected by malignant pleural mesothelioma (MPM) to identify potential predictive biomarkers of therapy response, toxicity development, and eligibility for further immunotherapeutic treatments. Blood samples were collected from 55 patients with MPM, enrolled in a phase 3 trial comparing radical hemithoracic RT (interventional arm, n=28) with local palliative RT (control arm, n=27). Immunomonitoring was performed before RT, at the end of treatment, and 1 month after therapy, characterizing natural killer cells, B and T lymphocytes, activated CD4 and CD8 T cells, interferon-γ- and tumor necrosis factor-α-producing T helper (Th) 1 cells, regulatory T cells, and Th17 and Th22 lymphocytes, through flow cytometry. Serum levels of interleukin (IL)-6, -8, -10 and mesothelin were quantified through Enzyme-Linked Immunosorbent Assay (ELISA) assays at the same time points. Variations in the immune parameters were investigated by Friedman test and Wilcoxon signed rank post hoc test with Bonferroni correction for multiple testing, while the prognostic effect of immune biomarkers was evaluated through Kaplan-Meier method and Spearman's correlation analysis. Major immune variations were noticed after radical RT compared with palliative treatment, in particular an improvement in activated T cells and in interferon-γ-producing Th1 cells after RT. In the interventional arm, baseline high levels of Th22 and IL-10 and an increase in T cells were associated with an improved survival, whereas a fold increase in serum mesothelin correlated with the development of severe toxicity. An improvement of immunosuppressive regulatory T cells was observed in both arms of treatment. The immunomonitoring performed in patients with MPM revealed potential prognostic biomarkers for radical hemithoracic RT treatment and identified specific immune signatures induced by RT immunomodulation, which could suggest a synergistic effect with an immunotherapeutic treatment.

Defining a prognostic risk score in ovarian cancer patients by integrated analysis of serum mesothelin, HE4, CA125 and surgical outcome.

e17611 Background: In ovarian cancer, serum CA125 is currently the only biomarker used in routine clinical practice and has several limitations, e.g. it is not entirely specific for ovarian malignancy. Alternative serum biomarkers have been proposed for ovarian cancer, such as mesothelin or human epididymis protein 4 (HE4). Although it is known that single marker analysis is often insufficient for diagnostic purposes or relapse prediction, no comprehensive studies on the combination of these markers have been conducted, yet. Using a multi-marker prediction model, we herein investigated the clinical usefulness of mesothelin and HE4, detected in a sequence of pre- and post-operative serum samples, in complementing the standard marker CA125. Methods: Serum mesothelin, HE4 and CA125 were quantified by Lumipulse G chemiluminescent enzyme immunoassay (Fujirebio) in a total of 432 serum samples from 90 healthy controls and 192 ovarian cancer patients (thereof 81.8% with FIGO III/IV), including 151 paired pre- and post-operative samples. Results: Pre-operative serum mesothelin and HE4 were significantly elevated compared to healthy controls with a median ratio (IQR) to controls of 2.6 and 9.6, respectively (p < 0.0001). High pre-operative levels of mesothelin or HE4 alone were significantly correlated with advanced FIGO-stage (p < 0.0001) and predicted surgical outcome (p < 0.0001). We retrospectively compiled mesothelin and HE4 levels with CA125, BRCA mutational status and surgical outcome, in order to define a multi-marker setting. Both, mesothelin and HE4 levels were independent from BRCA mutational status, however they positively correlated with CA125. Detection of pre-operative HE4 > 498pM (OR = 4.1, p < 0.0001) combined with pre-operative CA125 > 516U/mL (OR = 2.2, p = 0.001) was the best combination to predict surgical outcome (AUC = 0.815). Finally, we defined a prognostic signature, including pre-operative CA125, post-operative mesothelin, HE4 and surgical outcome, which was superior to the individual prognostic capacity of all included parameters. Our model allowed the calculation of a weighted risk score, stratifying patient at “lower risk” (score 0-4) or at “higher risk” (score 5-10). Patients with higher risk had significantly shorter PFS (19.0 months (95%CI = 16.1-21.8) vs 64.1 months (95%CI = 56.8-71.3) p < 0.0001) and OS (34.0 months (95%CI = 28.6-39.3) vs 71.2 months (95%CI = 64.6-77.7) p < 0.0001). Conclusions: This is the first study, proposing an integrated prognostic risk score for ovarian cancer patients, which could easily be implemented into routine diagnostics and may guide personalized treatment decisions. Patients at “higher risk”, as identified by this model, could potentially benefit from an intensified therapy regime, whereas patients at “lower risk” might be suitable for treatment de-escalation.

Low serum mesothelin in pancreatic cancer patients results from retention of shed mesothelin in the tumor microenvironment

Mesothelin (MSLN) is overexpressed by many cancers, including pancreatic ductal adenocarcinoma (PDAC) and has consequently become a target for anti-cancer therapeutics. Mature, membrane bound MSLN is cleaved by proteases, releasing a shed form that transits to the circulation. Many patients with mesothelioma and ovarian cancer have abnormally high serum MSLN concentration. However, serum MSLN concentration in PDAC patients rarely exceeds levels of healthy controls. Here, serum MSLN concentration in advanced PDAC patients was examined pre- and post-treatment. Serum MSLN did not correlate with tumor MSLN expression, nor with changes in tumor burden as assessed by PDAC serum tumor marker CA19–9. Subsequently, tumor-bearing mouse models were used to investigate the fate of shed MSLN in PDAC versus a control cervical cancer model. Efficiency of MSLN secretion into the serum was cell-line dependent. Tumors from some PDAC lines had poor MSLN secretion efficiency although these lines had similar or higher MSLN shedding rate, total and surface MSLN expression. Measurements of compartment-specific MSLN concentration taken at equilibrium suggested that tumors with poor MSLN secretion efficiency trapped shed MSLN in the tumor microenvironment (TME), a finding confirmed by dynamic experiments using a doxycycline-inducible MSLN expression system. Tumors with the poorest MSLN secretion efficiency had higher collagen density and increased abundance of MSLN binding partner MUC16. The tumor with the worst secretion efficiency could rebind shed MSLN to the cancer cell surface. Altogether, these data suggest that PDAC can trap shed MSLN within the TME. This finding has potential significance for design of MSLN-targeted therapeutics.

Clinical utility of diagnostic biomarkers in malignant pleural mesothelioma: a systematic review and meta-analysis.

Malignant pleural mesothelioma (MPM) is characterised by late-stage diagnosis and poor prognosis. Currently, no screening tool is advocated and diagnosis is based on invasive techniques, which are not well tolerated. Non-invasive diagnostic biomarkers have shown potential and could have a huge clinical benefit. However, despite extensive research, there is no consensus yet on their clinical use, with many articles reporting contradicting results, limiting their clinical implementation. The aim of this systematic review is therefore to explore the different semi- and non-invasive diagnostic markers in several human matrices and identify those that might clinically be relevant. A total of 100 articles were selected through Web of Science and PubMed, with 56 articles included in the quantitative analysis. Although many studies have reported on the diagnostic accuracy of MPM biomarkers such as serum mesothelin and high-mobility group box protein 1 and plasma fibulin-3, none have resulted in a validated test for early detection. Future research should focus on external validation, combinations into biomarker panels, the inclusion of early stage MPM patients and a combination of different biomarker matrices, as well as new markers.

Serum Proteomics and Plasma Fibulin-3 in Differentiation of Mesothelioma From Asbestos-Exposed Controls and Patients With Other Pleural Diseases

IntroductionMalignant pleural mesothelioma (MPM) is difficult to diagnose. An accurate blood biomarker could prompt specialist referral or be deployed in future screening. In earlier retrospective studies, SOMAscan proteomics (Somalogic, Boulder, CO) and fibulin-3 seemed highly accurate, but SOMAscan has not been validated prospectively and subsequent fibulin-3 data have been contradictory. MethodsA multicenter prospective observational study was performed in 22 centers, generating a large intention-to-diagnose cohort. Blood sampling, processing, and diagnostic assessment were standardized, including a 1-year follow-up. Plasma fibulin-3 was measured using two enzyme-linked immunosorbent assays (CloudClone [used in previous studies] and BosterBio, Pleasanton, CA). Serum proteomics was measured using the SOMAscan assay. Diagnostic performance (sensitivity at 95% specificity, area under the curve [AUC]) was benchmarked against serum mesothelin (Mesomark, Fujirebio Diagnostics, Malvern, PA). Biomarkers were correlated against primary tumor volume, inflammatory markers, and asbestos exposure. ResultsA total of 638 patients with suspected pleural malignancy (SPM) and 110 asbestos-exposed controls (AECs) were recruited. SOMAscan reliably differentiated MPM from AECs (75% sensitivity, 88.2% specificity, validation cohort AUC 0.855) but was not useful in patients with differentiating non-MPM SPM. Fibulin-3 (by BosterBio after failed CloudClone validation) revealed 7.4% and 11.9% sensitivity at 95% specificity in MPM versus non-MPM SPM and AECs, respectively (associated AUCs 0.611 [0.557–0.664], p = 0.0015) and 0.516 [0.443–0.589], p = 0.671), both inferior to mesothelin. SOMAscan proteins correlated with inflammatory markers but not with asbestos exposure. Neither biomarker correlated with tumor volume. ConclusionsSOMAscan may prove useful as a future screening test for MPM in asbestos-exposed persons. Neither fibulin-3 nor SOMAscan should be used for diagnosis or pathway stratification.

Potential role of serum mesothelin in predicting survival of patients with malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is an aggressive tumor with poor survival rates. Therefore, it is essential to have effective biological markers predicting the course of the disease and prognosis. The aim of the present study was to highlight the prognostic significance of serum soluble mesothelin-related protein (Se-SMRP) in patients with MPM at diagnosis. Se-SMRP was determined in 60 patients using an ELISA commercial kit. Se-SMRP levels were subdivided into three tertile-based categories and in each category overall survival (OS) indexes were determined using the Kaplan-Meier and Cox regression analyses. The association between Se-SMRP levels and OS was also assessed by restricted cubic spline (RCS) analysis. No notable differences in the Kaplan-Meier probabilities were identified across the Se-SMRP categories (<0.66 nM, 0.66-1.46 nM, >1.46 nM) although an upward trend in death rate ratios (RR) was pointed out by comparing the higher (RR=1.95) and intermediate (RR=1.86) categories with the lower category (RR=1.00). In addition, such an increasing tendency, particularly when the biomarker exceeded 1.0 nM, was confirmed by an RCS function of Se-SMPR levels fitted to survival data using the Cox regression equation. The present study provided evidence in favor of a prognostic value of Se-SMRP in patients with MPM.

Randomized phase 2 study of maintenance pemetrexed (Pem) versus observation (Obs) for patients (pts) with malignant pleural mesothelioma (MPM) without progression after first-line chemotherapy: Cancer and Leukemia Group B (CALGB) 30901 (Alliance).

8517 Background: Standard front-line chemotherapy for advanced MPM is (Pem and a platinum; optimal treatment duration is unknown. We performed a randomized phase 2 trial (NCT01085630) to determine if continuation of single-agent Pem after 4-6 cycles of Pem-platinum would improve progression-free survival (PFS). Methods: Eligible pts had histologically confirmed unresectable MPM, and performance status (PS) 0-1. Pts with at least stable disease following 4-6 cycles of Pem-platinum were stratified by first-line regimen (cis- or carboplatin) and histology (epithelioid versus other) and randomized 1:1 to Obs or continuation of Pem until progression. The primary endpoint was PFS. We assumed that Obs produced a median (m) PFS of 3 months (mo) and Pem would yield a 100% improvement in mPFS to 6 mo; 60 eligible pts (30 per arm) were to be randomized. Results: 72 pts from 30 sites registered 12/10-6/16. The study closed early due to slow accrual once 53 pts were randomized; 49 eligible pts (22 Obs, 27 Pem) are included in the efficacy analysis. Pt characteristics (Obs/Pem): age: median (range) 70 (39-85)/70 (52-87); male 68%/78%; PS 0 27%/33%; epithelioid histology 77%/70%; first-line cisplatin 27%/26%. A median of 4 cycles of Pem (range 1-33) was delivered; 22% of pts required dose modification. mPFS was 3 mo on Obs and 3.4 mo on Pem (hazard ratio (HR) 0.99; 95% CI: 0.51-1.90; p=0.9733). Median overall survival (mOS) was 11.8 mo for Obs, and 16.3 mo for Pem (HR 0.86; 95% CI 0.44-1.71; p=0.6737). Toxicities ≥ grade 3 on Pem included anemia 8%, lymphopenia 8%, neutropenia 4%, and fatigue 4%; there were no grade 5 toxicities. A higher baseline level of serum mesothelin related peptide (SMRP) was associated with worse PFS (HR 1.861, p=0.049). Baseline osteopontin did not significantly affect PFS (p=0.3630). Conclusions: Although it was well tolerated, maintenance Pem following initial Pem/platinum doublet chemotherapy does not improve PFS in MPM patients. High baseline SMRP was associated with shorter PFS. Support: U10CA180821, U10CA180882; https://acknowledgments.alliancefound.org . Clinical trial information: NCT01085630.

Variation of serum mesothelin related proteins and of the tumor burden assessed by mRECIST criteria in patients with malignant pleural mesothelioma: An exploratory analysis

Variation of serum mesothelin related proteins and of the tumor burden assessed by mRECIST criteria in patients with malignant pleural mesothelioma: An exploratory analysis

Serum mesothelin as a circulating marker of diffuse malignant peritoneal mesothelioma: Preliminary study

Serum mesothelin as a circulating marker of diffuse malignant peritoneal mesothelioma: Preliminary study

A prospective study to investigate the role of serial serum mesothelin in monitoring mesothelioma

BackgroundRadiological monitoring of malignant pleural mesothelioma (MPM) using modified RECIST criteria is limited by low sensitivity and inter-observer variability. Serial serum mesothelin measurement has shown utility in the assessment of treatment response during chemotherapy but has never been assessed in the longer term follow up of patients.MethodsThis is a single centre study of consecutive patients diagnosed with MPM who received chemotherapy or best supportive care (BSC). Serum mesothelin measurements with paired 6 monthly CT scans were performed following the completion of chemotherapy, or from baseline in the BSC group. Changes in mesothelin were correlated with radiological progression and overall survival.ResultsForty-one patients with MPM were recruited and followed up for a minimum of 12 months (range 12–21 months). The majority of patients (n = 23) received chemotherapy with pemetrexed and cisplatin. Across the cohort a 10% rise in serum mesothelin could predict radiological progression with a sensitivity of 96% (IQR; 79–100) and specificity of 74% (IQR; 50–91). Sensitivity fell to 80% in sarcomatoid only disease. Patients with a rising mesothelin at 6 months had significantly worse overall survival (175 days) compared to stable/falling levels (448 days) (p = 0.003).ConclusionsThis is the first study to assess serum mesothelin’s ability to detect progression of MPM following chemotherapy or during BSC. A 10% rise in serum mesothelin level showed excellent sensitivity at predicting progressive disease. Mesothelin measurement has several advantages over serial CT imaging including reducing hospital visits and cost.

Mesothelin and osteopontin as circulating markers of diffuse malignant peritoneal mesothelioma: A preliminary study

BackgroundThe differential diagnosis between diffuse malignant peritoneal mesothelioma (DMPM) and other peritoneal surface malignancies (PSM) is still challenging. Serum mesothelin and osteopontin are increasingly used as markers of pleural mesothelioma, but their role in DMPM is unclear. We assessed the diagnostic and prognostic values of mesothelin, osteopontin, CEA, CA19.9, CA125, and CA15.3 in DMPM patients. MethodsMarkers were dosed before cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (HIPEC) by enzyme-linked immunosorbent assay (ELISA) in 30 DMPM patients and 14 controls with other PSMs. Receiver-operating characteristics (ROC) curve were plotted. The performance of each marker was assessed by the area under the ROC curve (AUC-ROC). ResultsMean mesothelin levels were 7.84 ng/dl (SD = 5.14) in DMPM group and 3.00 ng/dl (SD = 1.25) in controls (P = 0.001). Mean CEA levels were 5.3 ng/dl (SD = 4.7), and 61.96 ng/dl (SD = 112.5) in the two groups (P = 0.008). No statistical difference was seen for osteopontin (P = 0.738), CA19.9 (P = 0.081), CA125 (P = 0.600), and CA15.3 (P = 0.365). AUC-ROC was 0.836 for CA19.9, 0.812 for mesothelin, 0.793 for CEA, and lower for CA125 (0.652), osteopontin (0.531), and CA15.3 (0.481). Using diagnostic cut-offs selected by ROC methodology, sensitivity, specificity, positive and negative predictive values were 70.0%, 100.0%, 100.0%, and 60.9% for mesothelin >5.21 ng/dl, and 90.0%, 85.7%, 93.1%, and 80.0% for CA19.9 < 8.8 U/dl. At multivariate analysis, osteopontin correlated with survival (hazard rate 6.46; 95%CI 1.81–23.05; P = 0.004). ConclusionWhen assessing PSMs of unknown origin, elevated mesothelin with low CA19.9 may increase the suspicion index for DMPM. Ospeopontin warrants further investigations as a prognostic marker for DMPM.

Serum mesothelin and other biomarkers: what have we learned in the last decade?

In the last decade there is been much interest in noninvasive, economic and well-accepted diagnostic tests for screening of subjects exposed to asbestos, and in patients with malignant pleuric mesothelioma (MPM) for diagnosis or monitoring response to treatment. Several biomarkers have been suggested as tools for screening and early diagnosis of MPM. Currently, in patients with MPM, have been reported high levels of soluble mesothelin-related peptides (SMRP), plasmatic osteopontin (pOPN), vimentin, fibulin-3 and many others as promising marker for diagnosis, even their use in prevention monitoring is still discussed. In this type of disease, a key role could be played by miRNAs, which expression has been investigated in a large series of MPM to examine new pathways useful in diagnosis, prognosis and therapy. An altered expression of some proteins has been reported, useful as biomarkers, in comparative proteomic analysis of malignant pleural mesothelioma. New promising markers are nowadays under study and alone or better in combination, they'll be very helpful in diagnosing, monitoring mesothelioma patients or for screening of risk groups.

Overexpression of periostin and distinct mesothelin forms predict malignant progression in a rat cholangiocarcinoma model.

Periostin and mesothelin have each been suggested to be predictors of poor survival for patients with intrahepatic cholangiocarcinoma, although the clinical prognostic value of both of these biomarkers remains uncertain. The aim of the current study was to investigate these biomarkers for their potential to act as tumor progression factors when assessed in orthotopic tumor and three‐dimensional culture models of rat cholangiocarcinoma progression. Using our orthotopic model, we demonstrated a strong positive correlation between tumor and serum periostin and mesothelin and increasing liver tumor mass and associated peritoneal metastases that also reflected differences in cholangiocarcinoma cell aggressiveness and malignant grade. Periostin immunostaining was most prominent in the desmoplastic stroma of larger sized more aggressive liver tumors and peritoneal metastases. In comparison, mesothelin was more highly expressed in the cholangiocarcinoma cells; the slower growing more highly differentiated liver tumors exhibited a luminal cancer cell surface immunostaining for this biomarker, and the rapidly growing less differentiated liver and metastatic tumor masses largely showed cytoplasmic mesothelin immunoreactivity. Two molecular weight forms of mesothelin were identified, one at ∼40 kDa and the other, a more heavily glycosylated form, at ∼50 kDa. Increased expression of the 40‐kDa mesothelin over that of the 50 kDa form predicted increased malignant progression in both the orthotopic liver tumors and in cholangiocarcinoma cells of different malignant potential in three‐dimensional culture. Moreover, coculturing of cancer‐associated myofibroblasts with cholangiocarcinoma cells promoted overexpression of the 40‐kDa mesothelin, which correlated with enhanced malignant progression in vitro. Conclusion: Periostin and mesothelin are useful predictors of tumor progression in our rat desmoplastic cholangiocarcinoma models. This supports their relevance to human intrahepatic cholangiocarcinoma. (Hepatology Communications 2018;2:155–172)

Distribution and function of the complement protein C1q in malignant pleural mesothelioma microenvironment

Malignant pleural mesothelioma (MPM) is an asbestos-related cancer with a median survival of 12 months. The MPM incidence is 1–6/100,000 and is increasing as a result of historic asbestos exposure in industrialized countries and continued use of asbestos in developing countries. Lack of accurate biomarkers makes diagnosis, prognostication and treatment prediction of MPM challenging. The aim of this review is to identify the front line of MPM biomarkers with current or potential clinical impact. Literature search using the PubMed and PLoS One databases, the related-articles function of PubMed and the reference lists of associated publications until April 26th 2015 revealed a plethora of candidate biomarkers. The current gold standard of MPM diagnosis is a combination of two positive and two negative immunohistochemical markers in the epithelioid and biphasic type, but sarcomatous type do not have specific markers, making diagnosis more difficult. Mesothelin in serum and pleural fluid may serve as adjuvant diagnostic with high specificity but low sensitivity. Circulating proteomic and microRNA signatures, fibulin-3, tumor cell gene-ratio test, transcriptomic, lncRNA, glycopeptides, pleural fluid FISH assay, hyaluronate/N-ERC mesothelin and deformability cytometry may be important future markers. Putative predictive markers for pemetrexed–platinum are tumor TS and TYMS, for vinorelbine the ERCC1, beta-tubuline class III and BRCA1. Mutations of the BAP1 gene are potential markers of MPM susceptibility. In conclusion, the current status of MPM biomarkers is not satisfactory but encouraging as more sensitive and specific non-invasive markers are emerging. However, prospective validation is needed before clinical application.

Midkine is a potential novel marker for malignant mesothelioma with different prognostic and diagnostic values from mesothelin

BackgroundWe evaluated possible diagnostic and prognostic values of serum midkine in malignant pleural mesothelioma in comparison with those of serum mesothelin, a well-established diagnostic biomarker.MethodsSerum mesothelin and midkine levels were determined with an enzyme-linked immunosorbent assay. We examined specimens from 95 Turkish cases with malignant pleural mesothelioma, 56 metastatic cancers to pleura, 27 other types of benign pleural diseases and 20 benign asbestos pleurisy. The cut-off values were 1.5 nmol/L for mesothelin and 421 pg/mL for midkine.ResultsSensitivity and specificity of mesothelin were 51.6 and 71.4%, 51.6 and 85.2%, and 51.6 and 85% for differentiating mesothelioma from metastatic cancers to pleura, other benign pleural diseases and benign asbestos pleurisy, respectively. Sensitivity and specificity of midkine were 61.1 and 41.1%, 61.1 and 48.1%, and 61.1 and 75% to distinguish mesothelioma from metastatic cancers to pleura, other benign pleural diseases and benign asbestos pleurisy, respectively. Combination of both biomarkers did not improve the differential diagnostic efficacy. Mesothelin levels were elevated in the epitheloid type and in the advanced cases, but were not related to the prognosis. In contrast, elevated baseline levels of midkine were independently associated with a poor prognosis of mesothelioma patients after adjusting for the stage, the histological subtypes and treatment schedules (HR = 1.84; 95% CI: 1.09-3.09) (p = 0.022).ConclusionsSerum mesothelin showed moderate sensitivity and high specificity to differentiate malignant pleural mesothelioma from metastatic malignancy to pleura and from benign pleural diseases. In contrast, midkine was a useful marker for predicting prognosis of mesothelioma patients.

Efficacy of Anti-mesothelin Immunotoxin RG7787 plus Nab-Paclitaxel against Mesothelioma Patient-Derived Xenografts and Mesothelin as a Biomarker of Tumor Response.

Purpose: The purpose of this study was to evaluate the antitumor efficacy of the reduced immunogenicity anti-mesothelin immunotoxin RG7787 plus nab-paclitaxel against primary mesothelioma cell lines and tumor xenografts and the utility of mesothelin as a biomarker of tumor response.Experimental Design: Early-passage human malignant mesothelioma cell lines NCI-Meso16, NCI-Meso19, NCI-Meso21, and NCI-Meso29 were evaluated for sensitivity to RG7787 or nab-paclitaxel alone or in combination. In addition, the antitumor activity of RG7787 plus nab-paclitaxel was evaluated using NCI-Meso16, NCI-Meso21, and NCI-Meso29 tumor xenografts in immunodeficient mice. Serum mesothelin was measured at different time points to determine whether its levels correlated with tumor response.Results: All four primary mesothelioma cell lines highly expressed mesothelin with 41 × 103 to 346 × 103 mesothelin sites per cell and were sensitive to RG7787, with IC50 ranging from 0.3 to 10 ng/mL. Except for NCI-Meso19, these cells were also sensitive to nab-paclitaxel, with IC50 of 10 to 25 ng/mL. In vitro, RG7787 plus nab-paclitaxel led to decreased cell viability compared with either agent alone. In NCI-Meso16 tumor xenografts, treatment with RG7787 plus nab-paclitaxel led to sustained complete tumor regressions. Similar antitumor efficacy was observed against NCI-Meso21 and NCI-Meso29 tumor xenografts. In all three tumor xenograft models, changes in human serum mesothelin correlated with response to therapy and were undetectable in mice with complete tumor regression with RG7787 and nab-paclitaxel.Conclusions: RG7787 plus nab-paclitaxel is very active against primary human mesothelioma cells in vitro as well as in vivo, with serum mesothelin levels correlating with tumor response. These results indicate that this combination could be useful for treating patients with mesothelioma. Clin Cancer Res; 23(6); 1564-74. ©2016 AACR.

Correlation Between Tumor Mesothelin Expression and Serum Mesothelin in Patients with Epithelial Ovarian Carcinoma: A Potential Noninvasive Biomarker for Mesothelin-targeted Therapy.

The cell surface glycoprotein mesothelin is highly expressed in several malignant diseases. Normal mesothelin expression is limited to mesothelial cells lining the pleura, peritoneum, and pericardium, making it a biomarker and an attractive target for cancer therapy. We investigated tumor mesothelin expression and serum mesothelin levels in patients with epithelial ovarian cancer or borderline tumors. In total, 161 patients selected from a previous prospective study were analyzed fortumor mesothelin expressionusing immunohistochemistry and serum mesothelin expressionusing enzyme-linked immunosorbent assay. Eighty-eight (68.8%) epithelial ovarian cancers and eight (24.2%) borderline tumors showed high mesothelin expression, which was associated with shorter progression-free and overall survival. The tumor mesothelin expression status was moderately correlated with serum mesothelin levels in epithelial ovarian cancer patients. Based on receiver operating characteristic analysis, a serum mesothelin level above 2.20nM predicted high tumor mesothelin expression in epithelial ovarian cancer patients (area under the curve=0.81). In 45 patients with recurrent epithelial ovarian cancer, we observed relatively lower levels of serum mesothelin, compared to the level at the primary diagnosis. We also tracked the change in the serum mesothelin level during the course of second-line chemotherapy and found a discrepancy between the clinical response and the serum mesothelin change in some patients, which suggested tumor heterogeneity among the tumor cells with or without mesothelin expression. Serum mesothelin may be a useful noninvasive biomarker surrogate for tumor mesothelin expression in future clinical trials for mesothelin-targeted therapy.

Serum Mesothelin, Osteopontin and Vimentin: Useful Markers for Clinical Monitoring of Malignant Pleural Mesothelioma

Malignant pleural mesothelioma (MPM) is a relatively rare tumor, with the epithelioid type occurring more frequently. Several biomarkers have been suggested for screening and early diagnosis of MPM. Currently, high levels of soluble mesothelin-related peptides (SMRP), plasma osteopontin (pOPN) and vimentin have been reported in patients with MPM as promising markers for diagnosis, but their clinical use in monitoring is still discussed. The aim of our study was to evaluate the usefulness of these substances as markers of the clinical response to treatment in patients suffering from epithelioid mesothelioma. 219 serum samples from 56 patients were collected during follow-up and the clinical response to therapy was recorded. Percentage differences between 2 consecutive measurements of SMRP, osteopontin and vimentin (Δ markers) by means of commercially available kits were correlated with changes in the clinical course. Δ SMRP, Δ pOPN and Δ vimentin showed statistically significant differences between the disease categories stable disease, partial response and disease progression (p = 0.0001, p = 0.035 and p = 0.0025 for SMRP, pOPN and vimentin, respectively). Moreover, contingency table analysis showed statistically significant differences between clinical response and Δ of each marker clustered into 3 groups (<-20%, between -20% and +20%, >+20%). The time course of Δ SMRP and Δ vimentin was strongly associated with disease status, and so was the time course of pOPN, albeit to a lesser extent. These markers appear to be particularly effective in cases of partial response and disease progression, while their possible use in stable disease should be better investigated.

P3.03-052 Diagnostic Utility of Mesothelin, Osteopontin and Megakaryocyte Potentiation Factor in Turkish Patients with Malignant Mesothelioma: Topic: Mesothelioma Clinical

Malignant mesothelioma (MM) is an agressive tumor with poor prognosis, thus early assessment is important. We investigated the presence of mesothelin, osteopontin and megakaryocyte potentiation factor (MPF) levels in both sera and pleural effusions of MM patients and compared to the lung cancer, other malignancy, exudative and transudative effusions. Patients were enrolled into 5 study groups as demonstrated in table 1. Serum and pleural mesothelin, osteopontin and MPF levels of study groups were measured with enzyme-linked immunosorbent assay and compared with using convenient statistical methods. Mesothelin and osteopontin levels in both sera and pleural effusions were found to be statistically different among groups (Table 1). Pleural mesothelin and osteopontin levels were significant parameters to differentiate MM from the other groups (p=0.0001; p=0.002 respectively). When cut off value of pleural mesothelin level was set at 169.6ng/mL, sensitivity was 71.4 % and specificity was 88% for MM. When cut off value of pleural osteopontin level was set at 521.25ng/mL, sensitivity was 64.3% and specificity was 80% for MM (Figure 1). Pleural but not sera MPF level of MM patients was significantly higher than patients with lung cancer (p=0.021). Mesothelin, osteopontin and MPF levels can be used as diagnostic bio-markers to detect MM.

Diagnostic and Prognostic Biomarkers in the Rational Assessment of Mesothelioma (DIAPHRAGM) study: protocol of a prospective, multicentre, observational study

IntroductionMalignant pleural mesothelioma (MPM) is an asbestos-related cancer, which is difficult to diagnose. Thoracoscopy is frequently required but is not widely available. An accurate, non-invasive diagnostic biomarker would allow early...