Malignant pleural mesothelioma: The standard of care and challenges for future management

Air pollution and survival in patients with malignant mesothelioma and asbestos-related lung cancer: a follow-up study of 1591 patients in South Korea

BACKGROUND

Despite significant advancements in treatments such as surgery, radiotherapy, and chemotherapy, the survival rate for patients with asbestos-related cancers remains low. Numerous studies have provided evidence suggesting that air pollution induces oxidative stress and inflammation, affecting acute respiratory diseases, lung cancer, and overall mortality. However, because of the high case fatality rate, there is limited knowledge regarding the effects of air pollution exposures on survival following a diagnosis of asbestos-related cancers. This study aimed to determine the effect of air pollution on the survival of patients with malignant mesothelioma and asbestos-related lung cancer.

METHODS

We followed up with 593 patients with malignant mesothelioma and 998 patients with lung cancer identified as asbestos victims between 2009 and 2022. Data on five air pollutants-sulfur dioxide, carbon monoxide, nitrogen dioxide, fine particulate matter with a diameter < 10 μm, and fine particulate matter with a diameter < 2.5 μm-were obtained from nationwide atmospheric monitoring stations. Cox proportional hazard models were used to estimate the association of cumulative air pollutant exposure with patient mortality, while adjusting for potential confounders. Quantile-based g-computation was used to assess the combined effect of the air pollutant mixture on mortality.

RESULTS

The 1-, 3-, and 5-year survival rates for both cancer types decreased with increasing exposure to all air pollutants. The estimated hazard ratios rose significantly with a 1-standard deviation increase in each pollutant exposure level. A quartile increase in the pollutant mixture was associated with a 1.99-fold increase in the risk of malignant mesothelioma-related mortality (95% confidence interval: 1.62, 2.44). For lung cancer, a quartile increase in the pollutant mixture triggered a 1.87-fold increase in the mortality risk (95% confidence interval: 1.53, 2.30).

CONCLUSION

These findings support the hypothesis that air pollution exposure after an asbestos-related cancer diagnosis can negatively affect patient survival.

Leptospermum extract (QV0) suppresses pleural mesothelioma tumor growth in vitro and in vivo by mitochondrial dysfunction associated apoptosis

Pleural mesothelioma (PM) is a highly aggressive, fast-growing asbestos-induced cancer with limited effective treatments. There has been interest in using naturally occurring anticancer agents derived from plant materials for the treatment of PM. However, it is unclear if an aqueous extract from Leptospermum polygalifolium (QV0) has activity against PM. Here we investigated the anti-cancer properties of QV0 and Defender^® (QV0 dietary formula) in vitro and in vivo, respectively. QV0 suppressed the growth of eight PM cell lines in a dose-dependent manner, effective at concentrations as low as 0.02% w/v (equivalent to 0.2 mg/ml). This response was found to be associated with inhibited cell migration, proliferation, and colony formation but without evident cell cycle alteration. We observed mitochondrial dysfunction post-QV0 treatment, as evidenced by significantly decreased basal and maximal oxygen consumption rates. Ten SCID mice were treated with 0.25 mg/g Defender^® daily and exhibited reduced tumor size over 30 days, which was associated with an average extension of seven days of mouse life. There was no evidence of liver toxicity or increased blood glucose post-treatment in animals treated with Defender^®. Significantly enhanced tumor apoptosis was observed in the Defender^®-treated animals, correlating to mitochondrial dysfunction. Lastly, the high levels of polyphenols and antioxidant properties of QV0 and Defender^® were detected in HPLC analysis. To the best of our knowledge, this study constitutes the first demonstration of an improved host survival (without adverse effects) response in a QV0-treated PM mouse model, associated with evident inhibition of PM cell growth and mitochondrial dysfunction-related enhancement of tumor apoptosis.

A novel pH sensitive theranostic PLGA nanoparticle for boron neutron capture therapy in mesothelioma treatment

This study aims to develop poly lactic-co-glycolic acid (PLGA) nanoparticles with an innovative imaging-guided approach based on Boron Neutron Capture Therapy for the treatment of mesothelioma. The herein-reported results demonstrate that PLGA nanoparticles incorporating oligo-histidine chains and the dual Gd/B theranostic agent AT101 can successfully be exploited to deliver a therapeutic dose of boron to mesothelioma cells, significantly higher than in healthy mesothelial cells as assessed by ICP-MS and MRI. The selective release is pH responsive taking advantage of the slightly acidic pH of the tumour extracellular environment and triggered by the protonation of imidazole groups of histidine. After irradiation with thermal neutrons, tumoral and healthy cells survival and clonogenic ability were evaluated. Obtained results appear very promising, providing patients affected by this rare disease with an improved therapeutic option, exploiting PLGA nanoparticles.

Recent Advances of Immune Checkpoint Inhibition and Potential for (Combined) TIGIT Blockade as a New Strategy for Malignant Pleural Mesothelioma

Malignant pleural mesothelioma (MPM) is a fatal cancer type that affects the membranes lining the lungs, and is causally associated with asbestos exposure. Until recently, the first-line treatment consisted of a combination of chemotherapeutics that only had a limited impact on survival, and had not been improved in decades. With the recent approval of combined immune checkpoint inhibition for MPM, promising new immunotherapeutic strategies are now emerging for this disease. In this review, we describe the current preclinical and clinical evidence of various immune checkpoint inhibitors in MPM. We will consider the advantages of combined immune checkpoint blockade in comparison with single agent checkpoint inhibitor drugs. Furthermore, recent evidence suggests a role for T cell immunoglobulin and ITIM domain (TIGIT), an inhibitory immunoreceptor, as a novel target for immunotherapy. As this novel immune checkpoint remains largely unexplored in mesothelioma, we will discuss the potential of TIGIT blockade as an alternative therapeutic approach for MPM. This review will emphasize the necessity for new and improved treatments for MPM, while highlighting the recent advances and future perspectives of combined immune checkpoint blockade, particularly aimed at PD-L1 and TIGIT.

Osteopontin, GLUT1 and Ki-67 expression in malignant peritoneal mesothelioma: prognostic implications

Background

Malignant peritoneal mesothelioma is the most common primary peritoneal neoplasm. The only universally recognised pathological prognostic factor is histopathological subtype. Prognostic markers based on patient features and clinical stages have been disappointing.

Aims

To assess the prognostic role of several clinicopathological features in a retrospective cohort of 60 patients diagnosed with peritoneal mesothelioma.

Methods

Sixty patients were centrally collected and were immunohistochemically analysed for the expression of osteopontin (OPN), GLUT1 and Ki‐67. Labelling was assessed by two pathologists. Complete clinical information and follow‐up were obtained from patients' records.

Results

OPN expression was identified in 52 (86.6%) of 60 specimens, and GLUT1 in 39 (65%) of 60 specimens. Univariate Cox regression analysis showed that a lower peritoneal carcinomatosis index (PCI), tumour‐directed treatment (chemotherapy or surgery alone or in any combination), lower Ki‐67, GLUT1 and lower OPN expression had a statistically significant positive effect on overall survival (OS). PCI (hazard ratio (HR) = 1.032 (95% confidence interval (CI): 1.000–1.067); P = 0.054) and tumour‐directed treatment (HR = 0.211 (95% CI: 0.104–0.430); P < 0.001), Ki‐67 (HR = 22.326 (95% CI: 3.523–141.498); P = 0.003) and OPN (HR = 7.268 (95% CI: 1.771–29.811); P = 0.009) retained independent prognostic significance in the multivariate analysis, all with a positive effect on OS with the exception of GLUT1.

Conclusions

OPN, Ki‐67, treatment and PCI were independent indicators for OS, and a higher level of OPN expression correlated significantly with poorer OS.

Epidemiology, diagnosis and treatment of the malignant pleural mesothelioma, a narrative review of literature

The malignant pleural mesothelioma is a very aggressive tumor which is arising from mesothelial cells and is associated with asbestos exposure. It is a heterogeneous cancer that shows a complex pattern of molecular changes, including genetic, chromosomic, and epigenetic abnormalities. The malignant pleural mesothelioma is characterized by a silent and slow clinical progression with an average period of 20–40 years from the asbestos exposure phase to the start of the symptoms. Unfortunately, to date, the therapeutic options are very limited, especially if the tumor is detected late. This narrative review provides an extended overview of the present evidence in the literature regarding the epidemiology, diagnostic pathways and treatment approaches of the malignant pleural mesothelioma. The treatment of mesothelioma has evolved slowly over the last 20 years not only from a surgical point of view but also radiotherapy, chemotherapy and immunotherapy play nowadays a key role. Several surgical strategies are available ranging from extrapleural pneumonectomy to cytoreductive surgery but a multidisciplinary approach seems to be mandatory because a single approach has not proved to date to be resolutive. New non-surgical treatment options appear to be promising but the results have to be taken in account with caution because clear evidence with high-quality studies is still lacking

Metastasis-associated gene 1 (MTA1) enhances cisplatin resistance of malignant pleural mesothelioma by ATR-Chk1-mediated DNA repair

Background

Malignant pleural mesothelioma (MPM) chemoresistance remains a challenge to oncologists. In our previous study, we demonstrated that the aberrant expression of metastasis-associated gene 1 (MTA1) is associated with carcinogenesis and metastasis in MPM. The aim of the present study was to investigate the mechanism of MTA1 and chemo-resistance in MPM.

Methods

Western blotting and real-time polymerase chain reaction were used to analyze the protein and mRNA levels. A stable clone with a knockdown of MTA1 was generated with shRNA via lentivirus technology in MPM cell lines. Cell Counting Kit-8 assay and crystal violet assay were used to measure cell viability. Immunochemical staining was employed to detect MTA1 expression in MPM tissues. The cell cycle of MPM cells was determined by phosphohistone H3 staining and flow cytometric analysis.

Results

The MTA1 protein was upregulated and enhanced cisplatin resistance in MPM. Cisplatin stabilized the expression of the MTA1 protein by inhibiting its ubiquitination, and MTA1 enhanced G2/M cell cycle delay and regulated and protected the tumor genome from chemotherapeutic drugs via participating in the phosphorylation of the ataxia telangiectasia mutated and rad3 related-checkpoint kinase 1 (ATR-Chk1) pathway.

Conclusions

These data suggest that MTA1 enhances cisplatin resistance by ATR-Chk1-mediated DNA damage repairment and cisplatin stabilizes MTA1 expression via affecting on the ubiquitination pathway of MTA1 in MPM. Our findings indicate that MTA1 could serve as a novel therapeutic target to overcome chemoresistance in MPM.

Circulating and local nuclear expression of survivin and fibulin-3 genes in discriminating benign from malignant respiratory diseases: correlation analysis

Survivin is an inhibitor of apoptosis as well as a promoter of cell proliferation. Fibulin-3 is a matrix glycoprotein that displays potential for tumor suppression or propagation. The present study aimed to validate the expression levels of survivin and fibulin-3 in benign and malignant respiratory diseases. This case-control study included 219 patients categorized into five groups. Group A included 63 patients with lung cancer, group B included 63 patients with various benign lung diseases, group D included 45 patients with malignant pleural mesothelioma (MPM), and group E included 48 patients with various benign pleural diseases. Group C included 60 healthy individuals (control group). Serum survivin and fibulin-3 levels were measured by ELISA, whereas their nuclear expressions in the lung and pleura were assessed via Western blot analysis. The results showed significantly higher survivin serum levels and significantly lower fibulin-3 levels in group A compared with in group B and controls (P<0.001). There were significantly higher serum levels of survivin and fibulin-3 in group D compared with in group E and controls (P<0.001), consistent with observed nuclear survivin and fibulin-3 expression levels. Fibulin-3 was determined to have higher value than survivin in discriminating lung cancer from MPM (P<0.05). Survivin and fibulin-3 could be useful diagnostic markers for lung and pleural cancers, and fibulin-3 expression was particularly useful in differentiating lung cancer from MPM.

CDKN2A and MTAP Are Useful Biomarkers Detectable by Droplet Digital PCR in Malignant Pleural Mesothelioma: A Potential Alternative Method in Diagnosis Compared to Fluorescence In Situ Hybridisation

Background

The diagnosis of malignant pleural mesothelioma (MPM) can be difficult, in part due to the difficulty in distinguishing between MPM and reactive mesothelial hyperplasia (RMH). The tumor suppressor gene, CDKN2A, is frequently silenced by epigenetic mechanisms in many cancers; in the case of MPM it is mostly silenced via genomic deletion. Co-deletion of the CDKN2A and methylthioadenosine phosphorylase (MTAP) genes has been researched extensively and discovered to be a highly specific characteristic of MPM. Most studies have used FISH to detect the deletion of CDKN2A and IHC for MTAP as a surrogate for this. In this study, we aim to investigate and validate droplet digital PCR (ddPCR) as an emerging alternative and efficient testing method in diagnosing MPM, by particularly emphasizing on the loss of MTAP and CDKN2A.

Methods

This study included 75 formalin fixed paraffin embedded (FFPE) MPM tissue, and 12 normal pleural tissue and 10 RMH as control. Additionally, primary MPM cell lines and normal pleural samples were used as biomarker detection controls, as established in our previous publication. All FFPE specimens were processed to isolate the DNA, that was subsequently used for ddPCR detection of CDKN2A and MTAP. FFPE samples were also analyzed by fluorescence in situ hybridization (FISH) for CDKN2A and MTAP deletion, and for MTAP IHC expression. Concordance of IHC and ddPCR with FISH were studied in these samples.

Results

95% and 82% of cases showed co-deletion of both MTAP and CDKN2A when determined by FISH and ddPCR respectively. ddPCR has a sensitivity of 72% and specificity of 100% in detecting CDKN2A homozygous loss in MPM. ddPCR also has a concordance rate of 92% with FISH in detecting homozygous loss of CDKN2A. MTAP IHC was 68% sensitive and 100% specific for detecting CDKN2A homozygous loss in MPM when these losses were determined by ddPCR.

Conclusion

Our study confirms that MTAP is often co-deleted with CDKN2A in MPM. Our in-house designed ddPCR assays for MTAP and CDKN2A are useful in differentiating MPM from RMH, and is highly concordant with FISH that is currently used in diagnosing MPM. ddPCR detection of these genetic losses can potentially be utilized as an alternative method in the diagnosis of MPM and for the future development of a less-invasive MPM-specific detection technique on MPM tumor tissue DNA.

Boron neutron capture therapy: Current status and future perspectives

The development of new accelerators has given a new impetus to the development of new drugs and treatment technologies using boron neutron capture therapy (BNCT). We analyzed the current status and future directions of BNCT for cancer treatment, as well as the main issues related to its introduction. This review highlights the principles of BNCT and the key milestones in its development: new boron delivery drugs and different types of charged particle accelerators are described; several important aspects of BNCT implementation are discussed. BCNT could be used alone or in combination with chemotherapy and radiotherapy, and it is evaluated in light of the outlined issues. For the speedy implementation of BCNT in medical practice, it is necessary to develop more selective boron delivery agents and to generate an epithermal neutron beam with definite characteristics. Pharmacological companies and research laboratories should have access to accelerators for large-scale screening of new, more specific boron delivery agents.

A Phase II Study of Pazopanib in Patients with Malignant Pleural Mesothelioma: NCCTG N0623 (Alliance)

PURPOSE

Preclinical and clinical data have shown promise in using antiangiogenic agents to treat malignant pleural mesothelioma (MPM). We conducted this phase II study to evaluate the efficacy and toxicity of single-agent pazopanib in patients with MPM.

MATERIALS AND METHODS

Patients with MPM who had received 0-1 prior chemotherapy regimens were eligible to receive pazopanib at a dose of 800 mg daily. The primary endpoint was progression-free survival rate at 6 months (PFS6), with a preplanned interim analysis for futility. Secondary endpoints included overall survival (OS), PFS, adverse events assessment and clinical benefit (complete response, partial response [PR], and stable disease [SD]).

RESULTS

Thirty-four evaluable patients were enrolled, with a median age of 73 years (49-84). The trial was closed early because of lack of efficacy at the preplanned interim analysis. Only 8 patients (28.6%; 95% confidence interval [CI], 13.2-48.7%) in the first 28 evaluable were progression-free at 6 months. PFS6 was 32.4% (95% CI, 17.4-50.5). There were 2 PR (5.9%) and 16 SD (47.1%). The overall median PFS and OS were 4.2 months (95% CI, 2.0-6.0) and 11.5 months (95% CI: 5.3-18.2), respectively. The median PFS and OS for the previously untreated patients was 5.4 months (95% CI, 2.7-8.5) and 16.6 months (95% CI, 6.6-30.6), respectively; and 2.0 months (95% CI, 1.3-4.2) and 5.0 months (95% CI: 3.0-11.9), respectively, for the previously treated patients. Grade 3 or higher adverse events were observed in 23 patients (67.6%).

CONCLUSION

Single-agent pazopanib was poorly tolerated in patients with MPM. The primary endpoint of PFS6 was not achieved in the current study. ClinicalTrials.gov identification number. NCT00459862.

IMPLICATIONS FOR PRACTICE

Single-agent pazopanib did not meet its endpoint in this phase II trial in malignant mesothelioma. Pazopanib is well tolerated in mesothelioma patients with a manageable toxicity profile. There is a need to better identify signals of angiogenesis that can be targeted in mesothelioma. Encouraging findings in frontline treatment warrant further investigations in combination with chemotherapy or immunotherapy.

Genomic analysis in short- and long-term patients with malignant pleura mesothelioma treated with palliative chemotherapy

BACKGROUND

Malignant pleural mesothelioma (MPM) is an aggressive tumour with poor prognosis. The aim of this study was to identify genetic mutations associated with poor or extended survival in patients who received palliative chemotherapy.

METHODS

A total of 720 patients diagnosed with MPM between 2005 and 2015 were identified. Overall survival (OS) was longer than 30 months from diagnosis for 27 patients. Twelve of 27 (44%) of the pleural biopsies from long-term survivors were retrieved and matched with 12 biopsies from patients who survived less than 12 months; one biopsy was then excluded for poor DNA quality.

RESULTS

A total of 11 patients had a mean OS of 5.5 months, whereas 12 patients lived more than 30 months (mean OS: 55.8 ± 25). Mutational analysis identified 428 alterations; of which, 148, classified as somatic and functional, were considered further. Among these, 85% were missense variants, 8% were variants causing a stop gain and 6% were splice variants. Loss-of-function mutations in UQCRC1 were significantly associated with reduced survival in patients with MPM (p = 0.027), while a higher frequency of mutations in MXRA5 and RAPGEF6 was registered in long-term survivors.

CONCLUSION

This is the first study evaluating the relationship between the mutational profile and outcome in patients with MPM after palliative chemotherapy. UQCRC1 codes for cytochrome b-c1 complex subunit 1 which plays a fundamental role in normal mitochondrial functions and in cell metabolism. Recent studies described UQCRC1 deregulation in other cancers. Our results suggest a possible role for mitochondrial metabolism in the biology of mesothelioma.

Nanotechnology in the diagnosis and treatment of lung cancer

Lung cancer is an umbrella term for a subset of heterogeneous diseases that are collectively responsible for the most cancer-related deaths worldwide. Despite the tremendous progress made in understanding lung tumour biology, advances in early diagnosis, multimodal therapy and deciphering molecular mechanisms of drug resistance, overall curative outcomes remain low, especially in metastatic disease. Nanotechnology, in particular nanoparticles (NPs), continue to progressively impact the way by which tumours are diagnosed and treated. The unique physicochemical properties of materials at the nanoscale grant access to a diverse molecular toolkit that can be manipulated for use in respiratory oncology. This realisation has resulted in several clinically approved NP formulations and many more in clinical trials. However, NPs are not a panacea and have yet to be utilised to maximal effect in lung cancer, and medicine in a wider context. This review serves to: describe the complexity of lung cancer, the current diagnostic and therapeutic environment, and highlight the recent advancements of nanotechnology based approaches in diagnosis and treatment of respiratory malignancies. Finally, a brief outlook on the future directions of nanomedicine is provided; presently the full potential of the field is yet to be realised. By gleaning lessons and integrating advancements from neighbouring disciplines, nanomedicine can be elevated to a position where the current barriers that stymie full clinical impact are lifted.

High BIN1 expression has a favorable prognosis in malignant pleural mesothelioma and is associated with tumor infiltrating lymphocytes

OBJECTIVES

A number of key immune regulators show prognostic value in malignant pleural mesothelioma (MPM), but the association between Bridging integrator 1 (BIN1), indoleamine 2,3 dioxygenase 1 (IDO1) and patient outcome has not been investigated. We aimed to determine the expression of BIN1 and IDO1, their association with other markers and impact on overall survival (OS) in MPM.

MATERIALS AND METHODS

The expression of BIN1, IDO1, CD3, CD20 and CD68 were evaluated by immunohistochemistry in 67 patients who underwent pleurectomy/decortication. Survival analyses were performed using the Kaplan Meier method and significant biomarkers were entered into a Cox Regression multivariate model, accounting for known prognostic factors such as age, gender, histological subtype, PD-L1 expression and neutrophil-to-lymphocyte ratio.

RESULTS

Immune markers were variably expressed in tumor cells, ranging from 0% to 100% for BIN1 (median: 89%), and 0% to 77.5% for IDO1 (median: 0%). Expression of markers of tumor-infiltrating lymphocytes (TILs) and macrophages ranged from 0% to more than 50%. BIN1 expression was high in 35 patients (51%) and was associated with increased OS (median: 12 vs 6 months for high and low BIN1 respectively,p = 0.03). Multivariate analysis showed BIN1 remained an independent prognostic indicator (HR 0.39; 95% CI: 0.18-0.82, p = 0.01). The majority of patients had immune inflamed tumors (77%) and there was a significant association between TILs and BIN1 (p = 0 < 0.01), PD-L1 (p=0.04) and CD68+ macrophages in the tumor (p < 0.01). There were no significant associations between PD-L1 and BIN1 or IDO1.

CONCLUSION

High BIN1 expression is a favorable prognostic biomarker and is associated with TILs in MPM.

Deep convolutional neural networks for the automated segmentation of malignant pleural mesothelioma on computed tomography scans

Tumor volume has been a topic of interest in the staging, prognostic evaluation, and treatment response assessment of malignant pleural mesothelioma (MPM). Deep convolutional neural networks (CNNs) were trained separately for the left and right hemithoraces on the task of differentiating between pleural thickening and normal thoracic tissue on computed tomography (CT) scans. A total of 4259 and 6192 axial sections containing segmented tumor were used to train the left-hemithorax CNN and the right-hemithorax CNN, respectively. Two distinct test sets of 131 sections from the CT scans of 43 patients were used to evaluate segmentation performance by calculating the Dice similarity coefficient (DSC) between deep CNN-generated tumor segmentations and reference tumor segmentations provided by a total of eight observers. Median DSC values ranged from 0.662 to 0.800 over the two test sets when comparing deep CNN-generated segmentations with observer reference segmentations. The deep CNN-based method achieved significantly higher DSC values for all three observers on the test set that allowed direct comparisons with a previously published automated segmentation method of MPM tumor on CT scans ( p < 0.0005 ). A deep CNN was implemented for the automated segmentation of MPM tumor on CT scans, showing superior performance to a previously published method.

A Clinical Trial of TumorGlow to Identify Residual Disease During Pleurectomy and Decortication

BACKGROUND

Macroscopic complete resection can improve survival in a select group of patients with malignant pleural mesothelioma. During resection, differentiating residual tumor from inflammation or scar can be challenging. This trial evaluated near-infrared (NIR) intraoperative imaging using TumorGlow (a novel NIR imaging approach utilizing high-dose indocyanine green and delayed imaging) technology to improve detection of macroscopic residual disease.

METHODS

Twenty subjects were enrolled in an open-label clinical trial of NIR intraoperative imaging with TumorGlow (Indocyanine Green for Solid Tumors [NCT02280954]). Twenty-four hours before pleural biopsy or pleurectomy and decortication (P/D), patients received intravenous indocyanine green. All specimens identified during standard-of-care surgical resection and with NIR imaging underwent histopathologic profiling and correlative microscopic fluorescent tomographic evaluation. For subjects undergoing P/D (n = 13), the hemithorax was evaluated with NIR imaging during P/D to assess for residual disease. When possible, additional fluorescent lesions were resected.

RESULTS

Of 203 resected specimens submitted for evaluation, indocyanine green accumulated within 113 of 113 of resected mesothelioma specimens, with a mean signal-to-background fluorescence ratio of 3.1 (SD, 2.2 to 4.8). The mean signal-to-background fluorescence ratio of benign tissues was 2.2 (SD, 1.4 to 2.4), which was significantly lower than in malignant specimens (p = 0.001). NIR imaging identified occult macroscopic residual disease in 10 of 13 subjects. A median of 5.6 resectable residual deposits per patient (range, 0 to 11 deposits per patient), with a mean size of 0.3 cm (range, 0.1 to 1.5 cm), were identified.

CONCLUSIONS

TumorGlow for malignant pleural mesothelioma is safe and feasible. Excellent sensitivity allows for to reliable detection of macroscopic residual disease during cytoreductive surgical procedures.

Near-Infrared Intraoperative Imaging Can Successfully Identify Malignant Pleural Mesothelioma After Neoadjuvant Chemotherapy

Malignant pleural mesothelioma is a deadly disease. Complete surgical resection provides patients with the best opportunity for long-term survival. Unfortunately, identification of disease during resection can be challenging. In this report, we describe successful intraoperative utilization of the near-infrared imaging agent, indocyanine green, to help the surgeon identify malignant disease in a patient with malignant pleural mesothelioma who had previously received neoadjuvant chemotherapy. This technology may ultimately enhance the thoracic surgeon's ability to identify small disease deposits at the time of resection.

An innovative therapeutic approach for malignant mesothelioma treatment based on the use of Gd/boron multimodal probes for MRI guided BNCT

The aim of this study is to develop an innovative imaging guided approach based on Boron Neutron Capture Therapy, for the treatment of mesothelioma, assisted by the quantification of the in vivo boron distribution by MRI. The herein reported results demonstrate that overexpressed Low Density Lipoproteins receptors can be successfully exploited to deliver to mesothelioma cells a therapeutic dose of boron (26 μg/g), significantly higher than in the surrounding tissue (3.5 μg/g). Boron and Gd cells uptake was assessed by ICP-MS and MRI on two mesothelioma (ZL34, AE17) and two healthy (MRC-5 and NMuMg) cell lines. An in vivo model was prepared by subcutaneous injection of ZL34 cells in Nu/Nu mice. After irradiation with thermal neutrons, tumor growth was evaluated for 40 days by MRI. Tumor masses of boron treated mice showed a drastic reduction of about 80-85%. The obtained results appear very promising providing patients affected by this rare disease with an improved therapeutic option, exploiting LDL transporters.

Proton beam therapy for malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is a rare disease with a poor prognosis. Surgical techniques have made incremental improvements over the last few decades while new systemic therapies, including immunotherapies, show promise as potentially effective novel therapies. Radiation therapy has historically been used only in the palliative setting or as adjuvant therapy after extrapleural pneumonectomy, but recent advances in treatment planning and delivery techniques utilizing intensity-modulated radiation therapy and more recently pencil-beam scanning (PBS) proton therapy, have enabled the delivery of radiation therapy as neoadjuvant or adjuvant therapy after an extended pleurectomy and decortication or as definitive therapy for patients with recurrent or unresectable disease. In particular, PBS proton therapy has the potential to deliver high doses of irradiation to the entire effected pleura while significantly reducing doses to nearby organs at risk. This article describes the evolution of radiation therapy for MPM and details how whole-pleural PBS proton therapy is delivered to patients at the Maryland Proton Treatment Center.

Content validity and ePRO usability of the BPI-sf and "worst pain" item with pleural and peritoneal mesothelioma

Background

The Brief Pain Inventory-short form (BPI-sf) is widely used in self-reported pain assessment, incorporates pain numeric rating scales (NRS) and is commonly utilized in electronic format in clinical trials, however, there is no published information about its usability as an electronic patient-reported outcome (ePRO) measure. The objective of this qualitative study was threefold: 1) to better understand pain experiences among patients with pleural or peritoneal mesothelioma; 2) to assess the interpretability of the instructions, item stem, recall period, and response option of the "worst pain" item of the BPI-sf; and 3) to examine the usability of the TrialMax Touch™ (CRF Health, Inc., Plymouth Meeting, PA) screen-based handheld device and the electronic format of the BPI-sf in a sub-sample of pleural mesothelioma patients.

Methods

A cross-sectional qualitative study was conducted among participants with pleural and peritoneal mesothelioma recruited from 4 clinical sites in the US. Semi-structured telephone or in-person interviews were conducted consisting of concept elicitation, cognitive interviewing of the 11-item BPI-sf, and in-person interview evaluation of ePRO assessment usability in pleural mesothelioma patients.

Results

Twenty-one participants recruited from 4 clinical sites in the US were interviewed in-person (n = 9) and by telephone (n = 12); 71% male; mean age 68.7 ± 13.6 years. Pleural and peritoneal patients described pain as ranging from discomfort to intense pain and reported being able to distinguish tumor pain from treatment pain. The BPI-sf "worst pain" item was relevant to, and easily understood by, study participants with pleural and peritoneal mesothelioma. The ePRO version was found to be easy to use, but readability of small font may be an issue. Participants reported minimal differences between their responses on the paper and ePRO version for all of the pain severity and pain interference items.

Conclusions

Results support the relevance and ease of understanding of the "worst pain" item and provide support for its content validity in patients with pleural and peritoneal mesothelioma. Usability of the ePRO format of the BPI-sf was confirmed for use in clinical trials among patients with pleural mesothelioma.

Live-Cell Mesothelioma Biobank to Explore Mechanisms of Tumor Progression

Experimental models closely representing in vivo conditions allow investigating mechanisms of resistance. Our aims were to establish a live-cell biobank of malignant pleural mesothelioma (MPM) samples and to obtain proof of principle that primary culture chemoresistant models, mimicking tumor progression observed in patients, can be obtained in vitro, providing a useful tool to investigate underlying mechanisms. Primary mesothelioma cultures were established from 235 samples between 2007 and 2014. Of two MPM patients, primary cultures obtained at different time points: at initial diagnosis, after neoadjuvant treatment at surgery and/or after tumor recurrence, were deeply investigated. Cells and corresponding tumor tissue were characterized by mesothelial protein and gene expression analysis. In addition, primary cultures from chemo naive patients were exposed to increasing doses of cisplatin/pemetrexed during three months and compared with non-treated cells in a cytotoxicity assay, and by selected profiling of senescence markers. In vitro chemoresistance in the primary mesothelioma cell cultures was associated with increased Thy1 (CD90) expression. Thy1 expression in MPM samples was significantly associated with poor overall survival in the TCGA MPM cohort. Our results illustrate that the establishment of a large live-cell MPM biobank contributes to a better understanding of therapy resistance observed in vivo, which eventually may lead to a more logical approach for developing new treatment strategies.

Radical multimodality therapy for malignant pleural mesothelioma

BACKGROUND

Malignant pleural mesothelioma is an almost always fatal tumour, for which palliative platinum-based chemotherapy is currently the standard treatment. Multimodal therapeutic strategies incorporating surgery, radiation therapy or photodynamic therapy and chemotherapy have been recommended for selected patients but there is no consensus about their effectiveness.

OBJECTIVES

To assess the benefits and harms of radical multimodal treatment options (including radical surgery ± radical radiotherapy ± photodynamic therapy ± systemic therapy) compared to each other or to palliative treatments, for people with malignant pleural mesothelioma.

SEARCH METHODS

We reviewed data from the Cochrane Lung Cancer group's Specialised Register, Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and Embase. We also checked reference lists of primary original studies, review articles and relevant conference proceedings manually for further related articles up to 21 March 2017.

SELECTION CRITERIA

We included parallel-group randomised controlled trials of multimodal therapy for people with malignant pleural mesothelioma (stages I, II or III) that measured at least one of the following endpoints: overall survival, health-related health-related quality of life, adverse events or progression-free survival. We considered studies regardless of language or publication status.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted relevant information on participant characteristics, interventions, study outcomes, and data on the outcomes for this review, as well as information on the design and methodology of the studies. Two review authors assessed the risk of bias in the included trials using pre-defined 'Risk of bias' domains. We assessed the methodological quality using GRADE.

MAIN RESULTS

We conducted this review in accordance with the published Cochrane protocol. Two randomised clinical trials with 104 participants fulfilled our inclusion criteria. Both trials were at high risk of bias (for outcomes other than overall survival), and we rated the evidence as moderate quality for overall survival and low quality for all other outcomes. One trial compared combined extrapleural pneumonectomy (EPP) plus neoadjuvant platinum-based chemotherapy plus postoperative high-dose hemithoracic radiotherapy with combined EPP plus platinum-based chemotherapy. The other trial compared EPP plus postoperative hemithoracic radiotherapy with standard (non-radical) therapy alone following platinum-based chemotherapy (patients in the standard therapy arm received continued oncological management according to local policy, which could include further chemotherapy or palliative radiotherapy).For the first trial, median overall survival calculated from registration was 20.8 months (95% confidence interval (CI) 14.4 to 27.8) in the no-radiotherapy group and 19.3 months (95% CI 11.5 to 21.8) in the radiotherapy group. For the second trial, median overall survival was 14.4 months (95% CI 5.3 to 18.7) for patients allocated to EPP and 19.5 months (95% CI 13.4 to time not yet reached) for patients randomised to standard non-radical therapy. In the second trial, 12 serious adverse events were reported during the study period: ten in the EPP group and two in the non-radical therapy group. Overall health-related quality of life scores were not different between the two arms in either study. We could not perform a meta-analysis of the two included trials due to clinical heterogeneity. We also identified three ongoing trials evaluating the topic of our review.

AUTHORS' CONCLUSIONS

The overall strength of the evidence gathered in this review is low and there is a lack of available evidence to support the use of radical multimodality therapy in routine clinical practice (particularly as one trial suggests greater harm). Given the added cost of multimodality treatment and the possible increase in risk of adverse effects, the lack of evidence of their effectiveness probably means that these interventions should currently be limited to clinical trials alone.

Large-scale copy number analysis reveals variations in genes not previously associated with malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is an aggressive tumor that is often causally associated with asbestos exposure. Comparative genomic hybridization techniques and arrays demonstrated a complex set of copy number variations (CNVs) in the MPM-genome. These techniques however have a limited resolution, throughput and flexibility compared to next-generation sequencing platforms.

In this study, the presence of CNVs in the MPM-genome was investigated using an MPM-cohort (N = 85) for which genomic microarray data are available through ‘The Cancer Genome Atlas’ (TCGA). To validate these results, the genomes of MPMs and matched normal samples (N = 21) were analyzed using low-pass whole genome sequencing on an ‘Illumina HiSeq’ platform. CNVs were detected using in-house developed analysis pipelines and frequencies of copy number loss and gain were calculated.

In both datasets, losses on chromosomes 1, 3, 4, 6, 9, 13 and 22 and gains on chromosomes 1, 5, 7 and 17 were found in at least 25% and 15% of MPMs, respectively. Besides the well-known MPM-associated genes, CDKN2A, NF2 and BAP1, other interesting cancer-associated genes were listed as frequently involved in a copy number loss (e.g. EP300, SETD2 and PBRM1). Moreover, four cancer-associated genes showed a high frequency of copy number gain in both datasets (i.e. TERT, FCGR2B, CD79B and PRKAR1A). A statistically significant association between overall survival and the presence of copy number loss in the CDKN2A-containing region was observed in the TCGA-set.

In conclusion, recurrent CNVs were detected in both datasets, occurring in regions harboring known MPM-associated genes and genes not previously linked to MPM.

Breath analysis by gas chromatography-mass spectrometry and electronic nose to screen for pleural mesothelioma: a cross-sectional case-control study

RATIONALE

Malignant pleural mesothelioma (MPM) is mainly caused by previous exposure to asbestos fibers and has a poor prognosis. Due to a long latency period between exposure and diagnosis, MPM incidence is expected to peak between 2020-2025. Screening of asbestos-exposed individuals is believed to improve early detection and hence, MPM management. Recent developments focus on breath analysis for screening since breath contains volatile organic compounds (VOCs) which reflect the cell's metabolism.

OBJECTIVES

The goal of this cross-sectional, case-control study is to identify VOCs in exhaled breath of MPM patients with gas chromatography-mass spectrometry (GC-MS) and to assess breath analysis to screen for MPM using an electronic nose (eNose).

METHODS

Breath and background samples were taken from 64 subjects: 16 healthy controls (HC), 19 asymptomatic former asbestos-exposed (AEx) individuals, 15 patients with benign asbestos-related diseases (ARD) and 14 MPM patients. Samples were analyzed with both GC-MS and eNose.

RESULTS

Using GC-MS, AEx individuals were discriminated from MPM patients with 97% accuracy, with diethyl ether, limonene, nonanal, methylcyclopentane and cyclohexane as important VOCs. This was validated by eNose analysis. MPM patients were discriminated from AEx+ARD participants by GC-MS and eNose with 94% and 74% accuracy, respectively. The sensitivity, specificity, positive and negative predictive values were 100%, 91%, 82%, 100% for GC-MS and 82%, 55%, 82%, 55% for eNose, respectively.

CONCLUSION

This study shows accurate discrimination of patients with MPM from asymptomatic asbestos-exposed persons at risk by GC-MS and eNose analysis of exhaled VOCs and provides proof-of-principle of breath analysis for MPM screening.

Biomarkers for early diagnosis of malignant mesothelioma: Do we need another moonshot?

Early diagnosis of malignant pleural mesothelioma (MPM) is a challenge for clinicians. The disease is usually detected in an advanced stage which precludes curative treatment. We assume that only new and non-invasive biomarkers allowing earlier detection will result in better patient management and outcome. Many efforts have already been made to find suitable biomarkers in blood and pleural effusions, but have not yet resulted in a valid and reproducible diagnostic one. In this review, we will highlight the strengths and shortcomings of blood and fluid based biomarkers and highlight the potential of breath analysis as a non-invasive screening tool for MPM. This method seems very promising in the early detection of diverse malignancies, because exhaled breath contains valuable information on cell and tissue metabolism. Research that focuses on breath biomarkers in MPM is in its early days, but the few studies that have been performed show promising results. We believe a breathomics-based biomarker approach should be further explored to improve the follow-up and management of asbestos exposed individuals.

MicroRNA-31 Regulates Chemosensitivity in Malignant Pleural Mesothelioma

Malignant pleural mesothelioma (MPM) is associated with an extremely poor prognosis, and most patients initially are or rapidly become unresponsive to platinum-based chemotherapy. MicroRNA-31 (miR-31) is encoded on a genomic fragile site, 9p21.3, which is reportedly lost in many MPM tumors. Based on previous findings in a variety of other cancers, we hypothesized that miR-31 alters chemosensitivity and that miR-31 reconstitution may influence sensitivity to chemotherapeutics in MPM. Reintroduction of miR-31 into miR-31 null NCI-H2452 cells significantly enhanced clonogenic resistance to cisplatin and carboplatin. Although miR-31 re-expression increased chemoresistance, paradoxically, a higher relative intracellular accumulation of platinum was detected. This was coupled to a significantly decreased intranuclear concentration of platinum. Linked with a downregulation of OCT1, a bipotential transcriptional regulator with multiple miR-31 target binding sites, we subsequently identified an indirect miR-31-mediated upregulation of ABCB9, a transporter associated with drug accumulation in lysosomes, and increased uptake of platinum to lysosomes. However, when overexpressed directly, ABCB9 promoted cellular chemosensitivity, suggesting that miR-31 promotes chemoresistance largely via an ABCB9-independent mechanism. Overall, our data suggest that miR-31 loss from MPM tumors promotes chemosensitivity and may be prognostically beneficial in the context of therapeutic sensitivity.

The Wnt regulator SFRP4 inhibits mesothelioma cell proliferation, migration, and antagonizes Wnt3a via its netrin-like domain

Secreted frizzled related proteins (SFRPs) are a family of Wnt regulators which are frequently downregulated in cancers. In malignant mesothelioma (MM), downregulation of SFRP4 has been reported as a mechanism which contributes to aberrant activation of oncogenic Wnt signaling. Here we investigated the biological consequences of SFRP4 in two mesothelioma cell models where this protein is downregulated. We used recombinant SFRP4 and transient overexpression to study changes in proliferation, migration and downstream signaling. We found that recombinant SFRP4 inhibited both proliferation and migration of MM cells as well as abrogating the stimulatory effect of recombinant Wnt3a. Morphologically SFRP4 induced a cytotoxic effect distinct from apoptosis and consistent with mitotic catastrophe. Overexpression of SFRP4 in these cell lines displayed similar effects as endogenous protein on cell viability, migration and nuclear morphology. We also used expression constructs to examine the role of the SFRP4 cysteine rich domain (CRD) and a netrin-like domain (NLD) in these effects. Interestingly, we found it was the NLD which mediated the biological effects of SFRP4 in these cells. Our results indicate that SFRP4 inhibits mesothelioma proliferation, migration and activates alternative cell death pathways. The finding that the NLD is responsible for these has broader implications for this protein family. Overall this study suggests that the Wnt pathway may prove a promising target for therapy in mesothelioma.

Intensity modulated radiation therapy after extra-pleural pneumonectomy for malignant pleural mesothelioma is feasible without fatal pulmonary toxicity and provides good survival

AIM

To analyze patterns of failure, toxicity, relapse-free survival (RFS), and overall survival (OS) in malignant pleural mesothelioma (MPM) patients treated with intensity-modulated radiation therapy following extrapleural pneumonectomy (EPP).

METHODS

We reviewed 18 charts of patients with MPM from 2005 to 2014 who underwent EPP followed by hemithoracic intensity-modulated radiation therapy. Intensity-modulated radiation therapy dose delivery adhered to published lung dose constraints. Kaplan-Meier curves were used to assess the RFS and OS. Median survival times are reported for both RFS and OS.

RESULTS

Median age was 65 years (range: 40-76 years). Chemotherapy was administered in four neo-adjuvant and seven adjuvant patients. Pathological American Joint Committee on Cancer stages II, III, IV, surgical margin, lympho-vascular space, pericardium, and chest wall involvement were seen in 3, 12, 3, 9, 7, 12 and 3 patients, respectively. The majority of the patients received 45 Gy in 25 fractions. The mean lung dose was 7.14 Gy (range: 5 Gy-9.3 Gy). The mean V20 was 2.23%. At a median follow-up of 3 years, eight patients were alive (44%); 10 experienced relapse (56%). Median RFS and OS were 24.4 months (95% CI: >16.3 months) and 38.2 months (95% CI: 17.4-78.1 months), respectively. Acute toxicities were fatigue, dermatitis, nausea, esophagitis/dysphagia, cough, and dyspnea on exertion. No grade III, IV, or fatal pulmonary toxicities were observed.

CONCLUSION

Intensity-modulated radiation therapy following EPP for MPM resulted in RFS and OS comparable to the published literature without significant toxicity.

LUME-Meso: Design and Rationale of the Phase III Part of a Placebo-Controlled Study of Nintedanib and Pemetrexed/Cisplatin Followed by Maintenance Nintedanib in Patients With Unresectable Malignant Pleural Mesothelioma

Malignant pleural mesothelioma (MPM) is a rare but aggressive disease: median survival is 6 to 9 months if untreated. Standard first-line treatment for patients with unresectable MPM is cisplatin/pemetrexed, with a median overall survival (OS) of approximately 1 year. Improvements in first-line treatment options are needed. With the benefit of combining bevacizumab with standard therapy shown in the Mesothelioma Avastin Cisplatin Pemetrexed Study (MAPS), vascular endothelial growth factor (VEGF) pathway inhibition has gained renewed interest as a treatment approach. Nintedanib is an oral angiokinase inhibitor targeting multiple signaling pathways implicated in the pathogenesis of MPM, including the VEGF receptor. The phase III part of the international, phase II/III LUME-Meso study is evaluating the efficacy and safety of nintedanib plus pemetrexed/cisplatin in patients with unresectable epithelioid MPM. Originally, this was a double-blind, randomized, phase II exploratory study and was amended to include a confirmatory phase III part following the recommendation of an internal Data Monitoring Committee and review of phase II data. The phase III part plans to enroll 450 chemotherapy-naive patients, who will be randomized to receive pemetrexed/cisplatin on day 1 and nintedanib or placebo on days 2 to 21, for a maximum of 6 cycles. Patients without disease progression who are eligible to continue study treatment will receive maintenance treatment with nintedanib or placebo until disease progression or undue toxicity. The primary end point is progression-free survival; OS is the key secondary end point. The study will use an adaptive design, including an interim analysis to reassess the number of OS events required to ensure sufficient power for OS analysis. The study is currently enrolling patients.

Detection of malignant pleural mesothelioma in exhaled breath by multicapillary column/ion mobility spectrometry (MCC/IMS)

Malignant pleural mesothelioma (MPM) is predominantly caused by previous asbestos exposure. Diagnosis often happens in advanced stages restricting any therapeutic perspectives. Early stage detection via breath analysis was explored using multicapillary column/ion mobility spectrometry (MCC/IMS) to detect volatile organic compounds (VOCs) in the exhaled breath of MPM patients in comparison to former occupational asbestos-exposed and non-exposed controls. Breath and background samples of 23 MPM patients, 22 asymptomatic former asbestos (AEx) workers and 21 healthy non-asbestos exposed persons were taken for analysis. After background correction, we performed a logistic least absolute shrinkage and selection operator (lasso) regression to select the most important VOCs, followed by receiver operating characteristic (ROC) analysis. MPM patients were discriminated from both controls with 87% sensitivity, 70% specificity and respective positive and negative predictive values of 61% and 91%. The overall accuracy was 76% and the area under the ROC-curve was 0.81. AEx individuals could be discriminated from MPM patients with 87% sensitivity, 86% specificity and respective positive and negative predictive values of 87% and 86%. The overall accuracy was 87% with an area under the ROC-curve of 0.86. Breath analysis by MCC/IMS allows MPM patients to be discriminated from controls and holds promise for further investigation as a screening tool for former asbestos-exposed persons at risk of developing MPM.

Low Merlin expression and high Survivin labeling index are indicators for poor prognosis in patients with malignant pleural mesothelioma

INTRODUCTION

Alterations of the tumor suppressor Neurofibromatosis type II (NF2) have been reported in about 40% of Malignant pleural mesothelioma (MPM) patients. NF2 (Merlin) deficiency leads to alterations of the Hippo pathway; resulting in activation of the oncogenic Yes Associated Protein-1 (YAP1). Our aim was to investigate the association between these alterations and clinical outcomes.

MATERIAL AND METHODS

Tissue microarrays composed of MPM tumors derived from 2 independent MPM cohorts were employed for this study. Immunohistochemical expression of Merlin, YAP1 and its target genes, Survivin and connective tissue growth factor (CTGF) were assessed in nuclear and cytoplasmic fractions. Cohort 1 was comprised of 145 patients intended to be treated with chemotherapy (CTX) followed by extrapleural pneumonectomy (EPP), thus both pre- and post-CTX tissues were available. Cohort 2 was comprised of 59 patients treated with EPP followed by intraoperative hyperthermic cisplatin and/or adjuvant CTX and/or radiotherapy. Marker expression was quantified by means of labeling index (%) for nuclear Survivin and by H-score for the other markers. The dichotomized marker expression was tested for the association with overall survival (OS) and freedom from recurrence (FFR).

RESULTS

Kaplan-Meier survival curves revealed a significant association between low cytoplasmic Merlin expression in pre-induction CTX tissues of cohort 1 with shorter FFR (p = 0.02) and OS (p = 0.03). The same tendency was observed in the chemotherapy naïve tissues obtained during EPP of cohort 2. Low nuclear Merlin expression in post-CTX tissues (available from cohort 1 only) was associated with shorter FFR (p = 0.04) and OS (p = 0.05). High nuclear Survivin labeling indices in both pre- and post-CTX tissues of cohort 1 was associated with shorter FFR (p = 0.02). In cohort 2, this was associated with both FFR and OS (p = 0.046 and p = 0.002, respectively). In multivariate analysis, low expression of cytoplasmic Merlin remained an independent prognosticator for shorter FFR of cohort 1 [hazard ratio (HR) = 0.5, 95% confidence interval (CI) = 0.3-0.9, p = 0.001] and OS [HR = 0.5, 95% CI = 0.3-1, p = 0.04]. High Survivin labeling index was an independent prognostic factor for shorter FFR in patients from cohort 1 [HR = 3.4, 95% CI = 1.7-6.8, p = 0.006] and shorter OS in patients from cohort 2 [HR = 2.35, 95% CI = 1.27-4.33, p = 0.006].

CONCLUSIONS

Our findings uncover the significance of Merlin protein expression and Survivin labeling index as prognosticators for poor clinical outcome in two independent MPM cohorts. If confirmed, these markers may be used to identify subgroups of patients benefitting from additional treatment.

The Genetic Landscape of Malignant Pleural Mesothelioma: Results from Massively Parallel Sequencing

Malignant pleural mesothelioma (MPM) is a rare yet aggressive tumor that is causally associated with-mostly professional-asbestos exposure. Given the long latency between exposure and disease, and because asbestos is still being used, MPM will remain a global health issue for decades to come. Notwithstanding the increasing incidence of MPM and the fact that patients with MPM face a poor prognosis, currently available treatment options are limited. To enable the development of novel targeted therapies, identification of the genetic alterations underlying MPM will be crucial. The first studies reporting on the genomic background of MPM identified recurrent somatic mutations in a number of tumor suppressor genes (i.e., cyclin-dependent kinase inhibitor 2A gene [CDKN2A], neurofibromin 2 (merlin) gene [NF2], and BRCA1 associated protein 1 gene [BAP1]). More recently, massively parallel sequencing strategies have been used and have provided a more genome-wide view on the genetic landscape of MPM. This review summarizes their results, describing alterations that cluster mainly in four pathways: the tumor protein p53/DNA repair, cell cycle, mitogen-activated protein kinase, and phosphoinisitide 3-kinase (PI3K)/AKT pathways. As these pathways are important during tumor development, they provide interesting candidates for targeting with novel drugs.

Modern management of malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is a deadly disease that produces a significant worldwide health care burden. The majority of cases are associated with prior asbestos exposure, but recent studies have identified a possible genetic predisposition in a minority of patients. Historically, obtaining a pathologic diagnosis of MPM was challenging, but with current pathological techniques, a secure diagnosis is possible in the majority of patients. Curative therapy for MPM remains elusive, and the primary treatment option for fit patients is platinum-based chemotherapy. Encouraging recent reports suggest that there may be a benefit to the addition of bevacizumab to standard chemotherapy as well as with the use of immune checkpoint inhibitors in MPM. Selected patients may be considered for aggressive surgical approaches, but there is considerable controversy regarding the true benefit of surgery and multimodality therapy in this disease.

Serendipitous discovery of peritoneal mesothelioma

We present the case of a 64-year-old patient with a history of Birt-Hogg-Dube syndrome, polycystic kidney disease treated with renal transplantation in May 2013, and multiple types of skin cancers, including malignant melanoma. He presented for lymphoscintigraphy for sentinel lymph node identification of the melanoma. Subsequent biopsy of the right axillary sentinel lymph node yielded a diagnosis of epithelial type malignant mesothelioma without a known primary tumor. Follow-up positron emission tomography with 2-deoxy-2-(fluorine-18)fluoro-D-glucose integrated with computed tomography (F-18 FDG PET/CT) demonstrated several suspicious hypermetabolic abdominal masses that were later confirmed to be epithelial-type mesothelioma via percutaneous biopsy.

Estimating the incidence of malignant mesothelioma in Vietnam: a pilot descriptive cancer registration study

INTRODUCTION

Global asbestos consumption has shifted toward lower income countries, particularly in the Asian region including Vietnam where asbestos and asbestos-containing products have been imported since the late 1960s.

METHODS

This pilot descriptive epidemiological study aimed to provide contemporary estimates of malignant mesothelioma incidence (histological subtype M9050/3; ICD-O-3) by gender and age group as recorded across nine cancer registries in Vietnam.

RESULTS

We identified 148 incident cases of malignant mesothelioma during 1987-2013. The majority of cases were recorded in the Hanoi region (n = 93) and were aged 55 years or older (n = 96).

DISCUSSION

By carefully reviewing existing cancer registry records in Vietnam, we identified a larger number of malignant mesothelioma cases than previously estimated. We recommend the use of cancer registry data in tracking future asbestos-related disease in Vietnam.

A proteomics-based approach identifies secreted protein acidic and rich in cysteine as a prognostic biomarker in malignant pleural mesothelioma

Background:

We aimed to identify prognostic blood biomarkers using proteomics-based approaches in malignant pleural mesothelioma (MPM).

Methods:

Plasma samples from 12 MPM patients were used for exploratory mass spectrometry and ELISA analyses. The significance of secreted protein acidic and rich in cysteine (SPARC) was examined in sera from a Dutch series (n=97). To determine the source of the circulating SPARC, we investigated SPARC expression in MPM tumours and healthy controls, as well as the expression and secretion from cell lines and xenografts.

Results:

Secreted protein acidic and rich in cysteine was identified as a putative prognostic marker in plasma. Validation in the Dutch series showed that the median survival was higher in patients with low SPARC compared with those with high SPARC (19.0 vs 8.8 months; P=0.01). In multivariate analyses, serum SPARC remained as an independent predictor (HR 1.55; P=0.05). In MPM tumour samples, SPARC was present in the tumour cells and stromal fibroblasts. Cellular SPARC expression was higher in 5 out of 7 cell lines compared with two immortalized mesothelial lines. Neither cell lines nor xenograft tumours secreted detectable SPARC.

Conclusions:

Low circulating SPARC was associated with favourable prognosis. Secreted protein acidic and rich in cysteine was present in both tumour cells and stromal fibroblasts; and our in vitro and in vivo experiments suggest that stromal fibroblasts are a potential source of circulating SPARC.

Clinical and pathologic predictors of clinical outcome of malignant pleural mesothelioma

AIMS AND BACKGROUND

Although worldwide use of asbestos has decreased, the incidence of malignant pleural mesothelioma (MPM) is expected to increase over the next few decades. A number of scoring systems has been proposed to assess clinicopathologic features and to predict the prognosis. We assessed the relationship between patients' features and disease evolution in order to choose the best treatment able to prolong overall survival (OS) and progression-free survival (PFS).

METHODS

We retrospectively analyzed patients with locally advanced or metastatic MPM, treated at the Department of Medical Oncology, Università Politecnica Marche, Italy, from January 2003 to September 2013. Data on age, sex, smoking history, asbestos exposure, performance status, tumor stage, histology, type of treatment, and routine laboratory tests including complete blood count panel, date of death, or censored status were collected. The OS and PFS were estimated using Kaplan-Meier method and Cox analysis was performed to analyze the prognostic relevance of clinical parameters.

RESULTS

We enrolled a total of 62 patients. Univariate analysis showed that histologic type, performance status, response to first-line therapy, pretreatment hemoglobin levels, and plasmatic Ca125 were significant prognostic factors. Conversely, no significant correlation was found between age, sex, smoking history, reported exposure to asbestos, stages at diagnosis, treatments, and OS and PFS.

CONCLUSIONS

Our results showed that anemia and increased Ca125 might be considered negative prognostic parameters in MPM patients and confirmed the prognostic role of histotype, performance status, and response to first-line chemotherapy.

HOX transcription factors are potential targets and markers in malignant mesothelioma

BACKGROUND

The HOX genes are a family of homeodomain-containing transcription factors that determine cellular identity during development and which are dys-regulated in some cancers. In this study we examined the expression and oncogenic function of HOX genes in mesothelioma, a cancer arising from the pleura or peritoneum which is associated with exposure to asbestos.

METHODS

We tested the sensitivity of the mesothelioma-derived lines MSTO-211H, NCI-H28, NCI-H2052, and NCI-H226 to HXR9, a peptide antagonist of HOX protein binding to its PBX co-factor. Apoptosis was measured using a FACS-based assay with Annexin, and HOX gene expression profiles were established using RT-QPCR on RNA extracted from cell lines and primary mesotheliomas. The in vivo efficacy of HXR9 was tested in a mouse MSTO-211H flank tumor xenograft model.

RESULTS

We show that HOX genes are significantly dysregulated in malignant mesothelioma. Targeting HOX genes with HXR9 caused apoptotic cell death in all of the mesothelioma-derived cell lines, and prevented the growth of mesothelioma tumors in a mouse xenograft model. Furthermore, the sensitivity of these lines to HXR9 correlated with the relative expression of HOX genes that have either an oncogenic or tumor suppressive function in cancer. The analysis of HOX expression in primary mesothelioma tumors indicated that these cells could also be sensitive to the disruption of HOX activity by HXR9, and that the expression of HOXB4 is strongly associated with overall survival.

CONCLUSION

HOX genes are a potential therapeutic target in mesothelioma, and HOXB4 expression correlates with overall survival.

Accelerated hemithoracic radiation followed by extrapleural pneumonectomy for malignant pleural mesothelioma

OBJECTIVE

To evaluate a new protocol of accelerated hemithoracic intensity-modulated radiation therapy (IMRT) followed by extrapleural pneumonectomy (EPP) for patients with resectable malignant pleural mesothelioma (MPM).

METHODS

A total of 25 Gy of radiation was delivered in 5 daily fractions over 1 week to the entire ipsilateral hemithorax with concomitant boost of 5 Gy to volumes at high risk based on computed tomography and positron emission tomography scan findings. EPP was performed at 6 ± 2 days after the end of radiation therapy. Adjuvant chemotherapy was offered to patients with ypN2 disease.

RESULTS

A total of 62 patients were included between November 2008 and October 2014. One patient died in the hospital 2 months after EPP, for an operative mortality of 1.6%, and 2 died after discharged from the hospital for an overall treatment-related mortality (grade 5 toxicity) of 4.8%. Twenty-four patients (39%) developed grade 3 to 5 (grade 3+) complications. On final pathology, 94% of the patients were stage III or IV, and 52% had ypN2 disease. The median survival for all patients as an intention-to-treat analysis was 36 months. The median overall survival and disease-free survival was 51 and 47 months, respectively, in epithelial subtypes, compared with 10 and 8 months in biphasic subtypes (P = .001). Ipsilateral chest recurrence occurred in 8 patients.

CONCLUSIONS

Accelerated hemithoracic IMRT followed by EPP has become our preferred approach for resectable MPM. The results have been encouraging in patients with epithelial subtype.

Surgery for malignant pleural mesothelioma

Malignant pleural mesothelioma is a locally aggressive asbestos-related cancer that has a worldwide distribution and an overall poor prognosis. The average median survival for patients receiving the current best nonsurgical therapy, cisplatin/pemetrexed chemotherapy, is between 7 and 13 months. In selected patients with early stage disease and favorable tumor characteristics, aggressive surgical management in combination with adjuvant or neoadjuvant therapy extends survival in up to 20% of patients. Despite the benefits of surgery for mesothelioma, many patients are not suitable for operative intervention due to advanced stage disease at presentation or the inability to tolerate aggressive surgical resection. The frontiers of mesothelioma research and treatment include an urgent search for biomarkers that can reliably detect early stage cancer in at-risk populations, clinical tests or indices that can reliably predict prognosis among surgical candidates and the development of efficacious drugs and targeted therapies that offer more durable local disease control.

Targeting immune checkpoints: New opportunity for mesothelioma treatment?

Malignant pleural mesothelioma is an aggressive cancer linked to asbestos exposure in most patients. Due to the long latency between exposure and presentation, incidence is expected to further increase in the next decade, despite the ban on asbestos import which occurred at the end of last century in industrialized countries. Platinum-based palliative chemotherapy is the only treatment with proven benefit on outcome, resulting in selected patients in a median overall survival of about 1 year. Therefore, there is room for therapeutic improvement using a new strategy to prolong survival. Dealing with cancer cell induced immunosuppression is a promising approach. Reactivating immune responses that are silenced by immune checkpoints recently gained a lot of interest. Checkpoint blockade has already shown promising preclinical and clinical results in several cancer types and is currently also being investigated in mesothelioma. Here, we discuss the expression patterns and mechanisms of action of CTLA-4 and PD-1 as the two most studied and of TIM-3 and LAG-3 as two interesting upcoming immune checkpoints. Furthermore, we review the clinical results of molecules blocking these immune checkpoints and point out their future opportunities with a special focus on mesothelioma.