Dendritic cells loaded with allogeneic tumour cell lysate plus best supportive care versus best supportive care alone in patients with pleural mesothelioma as maintenance therapy after chemotherapy (DENIM): a multicentre, open-label, randomised, phase 2/3 study.

BACKGROUND: Dendritic cell immunotherapy has proven to be safe and induces an immune response in humans. We aimed to establish the efficacy of dendritic cells loaded with allogeneic tumour cell lysate (MesoPher, Amphera BV, 's-Hertogenbosch, Netherlands) as maintenance therapy in patients with pleural mesothelioma. METHODS: In this open-label, randomised, phase 2/3 study, patients with histologically confirmed unresectable pleural mesothelioma, aged 18 years or older, with an Eastern Cooperative Oncology Group performance status score of 0-1, and non-progressing disease after four to six cycles of standard chemotherapy (with pemetrexed 500 mg/m2 plus platinum [cisplatin 75 mg/m2 or carboplatin area under the curve of 5]) were recruited from four centres in Belgium, France, and The Netherlands. Participants were randomly assigned (1:1), using block randomisation (block size of 4), stratified by centre and histology (epithelioid vs other), to MesoPher treatment plus best supportive care or best supportive care alone. Patients received up to a maximum of five MesoPher infusions, with treatment administered on days 1, 15, and 29, and weeks 18 and 30. At each timepoint, participants received an injection of 25 × 106 dendritic cells (two-thirds of the dendritic cells were administered intravenously and a third were injected intradermally). Best supportive care was per local institutional standards. The primary endpoint was overall survival, assessed in all participants randomly assigned to treatment (full analysis set) and safety assessed in all randomly assigned participants, and who underwent leukapheresis if they were in the MesoPher group. This study is registered with ClinicalTrials.gov, NCT03610360, and is closed for accrual. FINDINGS: Between June 21, 2018, and June 10, 2021, 176 patients were screened and randomly assigned to the MesoPher group (n=88) or best supportive care alone group (n=88). One participant in the MesoPher group did not undergo leukapheresis. Mean age was 68 years (SD 8), 149 (85%) of 176 were male, 27 (15%) were female, 173 (98%) were White, two were Asian (1%), and one (1%) was other race. As of data cutoff (June 24, 2023), after a median follow up of 15·1 months (IQR 9·5-22·4), median overall survival was 16·8 months (95% CI 12·4-20·3; 61 [69%] of 88 died) in the MesoPher group and 18·3 months (14·3-21·9; 59 [67%] of 88 died) in the best supportive care group (hazard ratio 1·10 [95% CI 0·77-1·57]; log-rank p=0·62). The most common grade 3-4 treatment-emergent adverse events were chest pain (three [3%] of 87 in the MesoPher group vs two [2%] of 88 in the best supportive care group), dyspnoea (none vs two [2%]), anaemia (two [2%] vs none), nausea (none vs two [2%]), and pneumonia (none vs two [2%]). No deaths due to treatment-emergent adverse events were recorded. Treatment-related adverse events consisted of infusion-related reactions (fever, chills, and fatigue), which occurred in 64 (74%) of 87 patients in the MesoPher group, and injection-site reactions (itch, erythema, and induration), which occurred in 73 (84%) patients, and all were grade 1-2 in severity. No deaths were determined to be treatment related. INTERPRETATION: MesoPher did not show improvement in overall survival in patients with pleural mesothelioma. Immune checkpoint therapy is now standard of care in pleural mesothelioma. Further randomised studies are needed of combinations of MesoPher and immune checkpoint therapy, which might increase efficacy without adding major toxicities. FUNDING: Amphera BV and EU HORIZON.

Characterization of Pleural Mesothelioma by Hierarchical Clustering Analyses Using Immune Cells within Tumor Microenvironment.

INTRODUCTION: Over the past decade, classifications using immune cell infiltration have been applied to many types of tumors; however, mesotheliomas have been less frequently evaluated. METHODS: In this study, 60 well-characterized pleural mesotheliomas (PMs) were evaluated immunohistochemically for the characteristics of immune cells within tumor microenvironment (TME) using 10 immunohistochemical markers: CD3, CD4, CD8, CD56, CD68, CD163, FOXP3, CD27, PD-1, and TIM-3. For further characterization of PMs, hierarchical clustering analyses using these 10 markers were performed. RESULTS: Among the immune cell markers, CD3 (p < 0.0001), CD4 (p = 0.0016), CD8 (p = 0.00094), CD163+ (p = 0.042), and FOXP3+ (p = 0.025) were significantly associated with an unfavorable clinical outcome. Immune checkpoint receptor expressions on tumor-infiltrating lymphocytes such as PD-1 (p = 0.050), CD27 (p = 0.014), and TIM-3 (p = 0.0098) were also associated with unfavorable survival. Hierarchical clustering analyses identified three groups showing specific characteristics and significant associations with patient survival (p = 0.016): the highest number of immune cells (ICHigh); the lowest number of immune cells, especially CD8+ and CD163+ cells (ICLow); and intermediate number of immune cells (ICInt). ICHigh tumors showed significantly higher expression of PD-L1 (p = 0.00038). Cox proportional hazard model identified ICHigh [hazard ratio (HR) = 2.90] and ICInt (HR = 2.97) as potential risk factors compared with ICLow. Tumor CD47 (HR = 2.36), tumor CD70 (HR = 3.04), and tumor PD-L1 (HR = 3.21) expressions were also identified as potential risk factors for PM patients. CONCLUSION: Our findings indicate immune checkpoint and/or immune cell-targeting therapies against CD70-CD27 and/or CD47-SIRPA axes may be applied for PM patients in combination with PD-L1-PD-1 targeting therapies in accordance with their tumor immune microenvironment characteristics.

Assessment of interferon-γ in pleural fluid as a prognostic factor of survival in malignant pleural mesothelioma.

BACKGOUND: Literature reports suggest that the host immune system may control Malignant Pleural Mesothelioma (MPM) growth, although its activity is limited by regulatory mechanisms. In this retrospective study, we analyzed the levels of pro-inflammatory (IL-1, IL-6, TNF), immune-regulatory (IL-10) and Th1/CTL-related cytokines (IL-12p70, IFN-γ) in the pleural exudate and their relationship with overall survival (OS) in MPM. METHODS: Cytokines were quantified by multiplexed immunoassay. Concentrations were dichotomized with respect to the median value. Correlation between cytokine level and OS was assessed using univariate (Kaplan-Meier curves) and multivariate (Cox regression) analyses. RESULTS: Regarding outcome, tumor histology, therapies undergone and IFN-γ were independent prognostic factors of OS in a 72 MPM training cohort. Notably, high concentrations of IFN-γ halved death probability (HR of high vs low IFN-γ concentration = 0.491, 95%CI 0.3-0.8, p = 0.007). Also in patients with epithelioid histology and those receiving at least one line of therapy, high IFN-γ level was an independent factor predictive of OS (HR of high vs low IFN-γ concentration were 0.497, p = 0.007 and 0.324, p = 0.006, respectively). However, these data were not confirmed in a 77 MPM validation cohort, possibly due to the low IFN-γ levels encountered in this population, and the heterogeneous distribution of disease stages between the training and the validation cohorts. None of the other cytokines showed any effect on survival. CONCLUSIONS: High level of IFN-γ in pleural effusion may be associated with better survival in MPM patients and potentially serve as a prognostic biomarker. Larger prospective studies are needed to ascertain this hypothesis.

Detection of circulating immunosuppressive cytokines in malignant pleural mesothelioma patients for prognostic stratification.

BACKGROUND: No data on circulating biomarkers for the prognostic stratification of Malignant Pleural Mesothelioma (MPM) patients are available. We prospectively explored the prognostic role of circulating monocyte and cytokine levels and their dynamic change during chemotherapy. PATIENTS AND METHODS: MPM patients receiving a first line treatment based on a platinum compound plus pemetrexed were eligible. Blood samples were collected at the baseline and at the end of induction chemotherapy. CCL-2, IL-10 and TGF-ß levels in plasma were quantified by Enzyme-Linked Immunosorbent Assay (ELISA); white blood cells, monocytes and platelets were evaluated by blood count test. RESULTS: Thirty-one patients were included in the study. Median overall survival (OS) was 12.13 months versus 9.6 months in patients with lower and higher monocytes count, respectively (p value = 0.02). We further stratified patients according to a combined score based on the association of IL-10, TGF-ß levels and monocytes count. High combined score was associated with shorter OS and PFS in univariate and multivariate analysis. Chemotherapy induced an increase in monocytes, IL-10, but not TGF-ß levels. CONCLUSION: The prognostic value of circulating levels of multiple immunosuppressive cytokines and inflammatory cells should be confirmed in a wider validation set of MPM patients.

Emerging biological therapies for the treatment of malignant pleural mesothelioma.

Introduction: Malignant pleural mesothelioma (MPM) has limited treatment options with minimal new therapy approvals for unresectable disease in the past 15 years. However, considerable work has occurred to develop immunotherapies and biomarker driven therapy to improve patient outcomes over this period.Areas covered: This review examines current standard of care systemic therapy in the first- and second line setting. The last 12 months has seen 2 significant trials (Checkmate 743 and CONFIRM) which provide evidence supporting the role of immunotherapy in the management of MPM. Further trials are underway to assess the role of combination chemoimmunotherapy and personalized therapy. Additionally, a large number of clinical trials are ongoing to assess the efficacy of oncoviral, dendritic cell, anti-mesothelin and chimeric antigen receptor T cell therapy in the treatment of MPM.Expert opinion: Recent Phase III trial results have established a role for immunotherapy in the management of MPM. The optimal sequencing and combination of chemotherapy and immunotherapy remains to be determined. Novel therapies for MPM are promising however efficacy remains to be determined and issues remain regarding access to and delivery of these therapies.

CD70 expression correlates with a worse prognosis in malignant pleural mesothelioma patients via immune evasion and enhanced invasiveness.

Diffuse malignant mesothelioma of the pleura (MPM) is a highly aggressive tumour that typically is associated with short survival. CD70 and CD27 belong to the tumour necrosis factor (TNF) and the TNF receptor (TNFR) superfamily, respectively. Under physiological conditions, the tightly regulated interaction between CD70 and CD27 plays a co-stimulatory role in promoting T-cell expansion and differentiation through the NFκB pathway. Aberrantly high CD70 expression has been documented in haematological and solid malignancies in association with immune evasion in malignant cells. In this study, 172 well-characterised primary diffuse MPM tumours including epithelioid (n = 145), biphasic (n = 15), and sarcomatoid (n = 12) histotypes were evaluated immunohistochemically for CD70, CD27, CD3, CD4, CD8, CD56, PDCD1 (PD-1), and FOXP3 expression. Twenty per cent (34/172) of the mesothelioma cells expressed CD70 on the cell membrane. Overall survival was significantly decreased in the cohort of patients with CD70-expressing tumour cells (p < 0.01). Patients with MPM containing a higher number of CD3+ (p < 0.01), CD4+ (p < 0.01), CD8+ (p < 0.01), or FOXP3+ (p < 0.01) tumour-infiltrating lymphoid cells (TILs) showed significantly worse clinical outcomes. As potential independent risk factors for MPM patients, multivariate Cox proportional hazards regression analysis revealed CD70 expression on mesothelioma cells [hazard ratio (HR) 2.25; p = 0.010], higher FOXP3+ TILs (HR 2.81; p = 0.004), and higher CD3+ TIL accumulation (HR 6.12; p < 0.001). In contrast, as a potential independent favourable factor, higher CD27+ TIL accumulation (HR 0.48; p = 0.037) was identified. In vitro experiments and an immunodeficient mouse model revealed that CD70 enhances the invasiveness of MPM cells through MET-ERK axis activation. Further analyses in syngeneic mouse models demonstrated possible roles for CD70 in immune evasion. Collectively, these findings suggest that the CD70-CD27 pathway enhances the malignant phenotypes of MPM and diminishes anti-tumor immune response in patients with these neoplasms. These markers might be useful in MPM for prognostic evaluations as well as targeted therapeutics. © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Durvalumab with first-line chemotherapy in previously untreated malignant pleural mesothelioma (DREAM): a multicentre, single-arm, phase 2 trial with a safety run-in.

BACKGROUND: There is a strong unmet need to improve systemic therapy in mesothelioma. Chemotherapy with cisplatin and pemetrexed improves survival in malignant pleural mesothelioma, and immune checkpoint inhibitors are an emerging treatment in this disease. We aimed to evaluate the activity of durvalumab, an anti-PD-L1 antibody, given during and after first-line chemotherapy with cisplatin and pemetrexed in patients with advanced malignant pleural mesothelioma. METHODS: DREAM was a multicentre, single-arm, open-label, phase 2 trial done in nine hospitals in Australia. Eligible patients were aged 18 years or older and had histologically confirmed malignant pleural mesothelioma considered unsuitable for cancer-directed surgery, an Eastern Cooperative Oncology Group performance status of 0 or 1, and measurable disease as per the modified Response Evaluation Criteria in Solid Tumors version 1.0 (mRECIST) for mesothelioma that was previously untreated with systemic therapy. All histological subtypes were eligible. The first six participants were treated for two cycles in a safety run-in. All participants received cisplatin 75 mg/m2, pemetrexed 500 mg/m2, and durvalumab 1125 mg intravenously on day 1 of a 3-weekly schedule for a maximum of six cycles. Change from cisplatin to carboplatin with an area under the curve of 5 was permitted. Durvalumab was continued for a maximum of 12 months. The primary endpoint was progression-free survival at 6 months, measured according to mRECIST for malignant pleural mesothelioma and analysed in the intention-to-treat population. Safety analyses included all participants who receive at least one dose of any study drug. This study is registered with the Australia New Zealand Clinical Trials Registry, ACTRN12616001170415. FINDINGS: Between Dec 28, 2016, and Sept 27, 2017, 55 participants were enrolled. 54 patients were eligible and were followed up for a median of 28·2 months (IQR 26·5-30·2). 31 (57%; 95% CI 44-70) of 54 patients were alive and progression-free at 6 months. The most common grade 3-4 adverse events were neutropenia (seven [13%] patients), nausea (six [11%]), and anaemia (four [7%]). A total of 60 serious adverse events occurred in 29 participants, five of which were considered possibly related to durvalumab. Five patients died during the study treatment; none of these five deaths were attributed to study treatment. INTERPRETATION: The combination of durvalumab, cisplatin, and pemetrexed has promising activity and an acceptable safety profile that warrants further investigation in a randomised phase 3 trial. FUNDING: AstraZeneca.

Expression of V-set immunoregulatory receptor in malignant mesothelioma.

Malignant mesothelioma is a highly lethal cancer. V-set immunoregulatory receptor (VSIR, also known as V-domain Ig suppressor T-cell activation, VISTA), a negative immune checkpoint regulator, was reported to be expressed in malignant mesothelioma; however, its detailed expression pattern and clinicopathological significance have not been elucidated. We examined the expression of VSIR and CD274 and CD8+ tumor-infiltrating lymphocytes in a total of 124 samples from 66 patients with malignant mesothelioma and analyzed the clinicopathological characteristics and their relationship with the immunohistochemical findings. A total of 553 non-small cell lung carcinomas were also evaluated for VSIR expression. VSIR expression was higher in epithelioid type mesothelioma (p < 0.001), whereas CD274 expression was higher in sarcomatoid type (p < 0.001). CD8+ tumor-infiltrating lymphocytes were more abundant in sarcomatoid mesotheliomas (p < 0.001), VSIR-low tumors (p = 0.045), and CD274-high tumors (p < 0.001). VSIR and CD274 were differentially expressed in each histological component of the biphasic type. VSIR expression was associated with favorable survival (p = 0.008). Two patients with VSIR-high tumors had received pembrolizumab; however, they showed progressive disease. No VSIR expression was observed in tumor cells of non-small cell lung carcinomas. In conclusion, VSIR expression may define a unique class of mesothelioma, characterized by predominantly epithelioid type and favorable prognosis. VSIR expression may be used as an immunohistochemical diagnostic marker for epithelioid mesothelioma. CD274 expression was associated with sarcomatoid mesothelioma and high infiltration of CD8+ lymphocytes. Because VSIR is a negative immune regulator and expressed in malignant mesothelioma, further study is warranted to investigate the therapeutic significance of VSIR blockade in this deadly cancer.

V-domain Ig-containing suppressor of T-cell activation (VISTA), a potentially targetable immune checkpoint molecule, is highly expressed in epithelioid malignant pleural mesothelioma.

V-domain Ig-containing suppressor of T-cell activation (VISTA) is an immune checkpoint gene that inhibits anti-tumor immune responses. Since most malignant pleural mesotheliomas do not respond to anti-programmed cell death(-ligand)1 (PD-(L)1)/cytotoxic T-lymphocyte-associated protein 4 (CTLA4) therapy and given the recent finding of The Cancer Genome Atlas Study that pleural mesothelioma displays the highest expression of VISTA among all cancers studied, we examined VISTA expression in a large pleural mesothelioma cohort. VISTA and PD-L1 immunohistochemistry were performed on tissue microarray of immunotherapy-naive pleural mesotheliomas (254 epithelioid, 24 biphasic and 41 sarcomatoid) and ten whole-tissue sections of benign pleura (VISTA only). Percentages of tumor and inflammatory cells with positive staining were assessed. Optimal prognostic cutoff percentages were determined using maximally selected rank statistics. Overall survival was evaluated using Kaplan-Meier methods and Cox proportional hazard analysis. All benign mesothelium expressed VISTA. Eighty-five percent of 319 and 38% of 304 mesotheliomas expressed VISTA and PD-L1 (88% and 33% of epithelioid, 90% and 43% of biphasic, and 42% and 75% of sarcomatoid), respectively. Median VISTA score was significantly higher in epithelioid (50%) (vs. biphasic [20%] and sarcomatoid [0]) (p < 0.001), while median PD-L1 score was significantly higher in sarcomatoid tumors (20%) (vs. biphasic and epithelioid [both 0%]) (p < 0.001). VISTA and PD-L1 were expressed in inflammatory cells in 94% (n = 317) and 24% (n = 303) of mesothelioma, respectively. Optimal prognostic cutoffs for VISTA and PD-L1 were 40% and 30%, respectively. On multivariable analysis, VISTA and PD-L1 expression in mesothelioma were associated with better and worse overall survival (p = 0.001 and p = 0.002), respectively, independent of histology. In a large cohort of mesothelioma, we report frequent expression of VISTA and infrequent expression of PD-L1 with favorable and unfavorable survival correlations, respectively. These findings may explain poor responses to anti-PD-(L)1 immunotherapy and suggest VISTA as a potential novel target in pleural mesothelioma.

Robust Cell Detection and Segmentation for Image Cytometry Reveal Th17 Cell Heterogeneity.

Image cytometry enables quantitative cell characterization with preserved tissue architecture; thus, it has been highlighted in the advancement of multiplex immunohistochemistry (IHC) and digital image analysis in the context of immune-based biomarker monitoring associated with cancer immunotherapy. However, one of the challenges in the current image cytometry methodology is a technical limitation in the segmentation of nuclei and cellular components particularly in heterogeneously stained cancer tissue images. To improve the detection and specificity of single-cell segmentation in hematoxylin-stained images (which can be utilized for recently reported 12-biomarker chromogenic sequential multiplex IHC), we adapted a segmentation algorithm previously developed for hematoxlin and eosin-stained images, where morphological features are extracted based on Gabor-filtering, followed by stacking of image pixels into n-dimensional feature space and unsupervised clustering of individual pixels. Our proposed method showed improved sensitivity and specificity in comparison with standard segmentation methods. Replacing previously proposed methods with our method in multiplex IHC/image cytometry analysis, we observed higher detection of cell lineages including relatively rare TH 17 cells, further enabling sub-population analysis into TH 1-like and TH 2-like phenotypes based on T-bet and GATA3 expression. Interestingly, predominance of TH 2-like TH 17 cells was associated with human papilloma virus (HPV)-negative status of oropharyngeal squamous cell carcinoma of head and neck, known as a poor-prognostic subtype in comparison with HPV-positive status. Furthermore, TH 2-like TH 17 cells in HPV-negative head and neck cancer tissues were spatiotemporally correlated with CD66b+ granulocytes, presumably associated with an immunosuppressive microenvironment. Our cell segmentation method for multiplex IHC/image cytometry potentially contributes to in-depth immune profiling and spatial association, leading to further tissue-based biomarker exploration. © 2019 International Society for Advancement of Cytometry.

About the diagnostic value of BAP-1 antibody in malignant pleural mesothelioma: a meta-analysis.

BACKGROUND: The positive diagnosis of MPM is based on morphologic features coupled with immunohistochemical findings. Many antibodies have been published especially in order to differentiate between malignant tumors and atypical mesothelial hyperplasia. BAP-1 is a BRCA1-binding protein whose loss of expression was frequently reported in MPM. Our aim was to assess the diagnostic value of this antibody in comparison to the most sensitive diagnostic antibody represented by the calretinin antibody. METHODS: We performed a meta-analysis using the Meta-Disc software 5.1.32. RESULTS: According to our inclusion criteria, 19 studies with 11 studies dealing with BAP1 antibody and 8 studies dealing with calretinin antibody were included. The SEN of BAP 1 and calretinin antibodies was respectively estimated to 54.6% and 86.5%. The SPE reached respectively 95.7% and 76.6%. The dOR was estimated respectively to 23.664 and 38.8. The I-square revealed a heterogeneity of the parameters studied. The metaregression analysis revealed as covariates the amplification system and the histologic subtype as causing effects of heterogeneity for BAP1 antibodies and histologic subtype and chromogene as causing effects of heterogeneity for calretinin antibody. CONCLUSION: This meta-analysis revealed that BAP1 antibody should be associated with more sensitive antibodies in order to assess the diagnosis.

Novel therapies for malignant pleural mesothelioma.

Malignant pleural mesothelioma is a rare cancer that is typically associated with exposure to asbestos. Patients with malignant pleural mesothelioma have poor outcomes with suboptimal therapeutic options and currently no treatment is curative. The standard frontline treatment, cisplatin plus pemetrexed chemotherapy, has only short and insufficient efficacy, and no validated treatment beyond first-line therapy is available. New therapeutic strategies are therefore needed. The addition of bevacizumab (an anti-VEGF antibody) combined with cisplatin plus pemetrexed has shown some promise. However, immunotherapy, especially immune checkpoint inhibitors, has generated a lot of excitement because of data suggesting the potential value of immune checkpoint inhibitors for patients who have failed chemotherapy. In this Review, we describe immune checkpoint inhibitors, other immunotherapies, targeted therapies, or combinations of novel drugs being investigated in malignant pleural mesothelioma, as well as the issues surrounding the selection of the best candidates for these treatments.

Malignant pleural mesothelioma immune microenvironment and checkpoint expression: correlation with clinical-pathological features and intratumor heterogeneity over time.

Background: Tumor immune microenvironment (TME) plays a key role in malignant pleural mesothelioma (MPM) pathogenesis and treatment outcome, supporting a role of immune checkpoint inhibitors as anticancer approach. This study retrospectively investigated TME and programmed death ligand 1 (PD-L1) expression in naïve MPM cases and their change under chemotherapy. Patients and methods: Diagnostic biopsies of MPM patients were collected from four Italian and one Slovenian cancer centers. Pathological assessment of necrosis, inflammation, grading, and mitosis was carried out. Ki-67, PD-L1 expression, and tumor infiltrating lymphocytes were detected by immunohistochemistry. When available, the same paired sample after chemotherapy was analyzed. Pathological features and clinical characteristics were correlated to overall survival. Results: TME and PD-L1 expression were assessed in 93 and 65 chemonaive MPM samples, respectively. Twenty-eight samples have not sufficient tumor tissue for PD-L1 expression. Sarcomatoid/biphasic samples were characterized by higher CD8+ T lymphocytes and PD-L1 expression on tumor cells, while epithelioid showed higher peritumoral CD4+ T and CD20+ B lymphocytes. Higher CD8+ T lymphocytes, CD68+ macrophages, and PD-L1 expression were associated with pathological features of aggressiveness (necrosis, grading, Ki-67). MPM cases characterized by higher CD8+ T-infiltrate showed lower response to chemotherapy and worse survival at univariate analysis. Patients stratification according to a combined score including CD8+ T lymphocytes, necrosis, mitosis, and proliferation index showed median overall survival of 11.3 months compared with 16.4 months in cases with high versus low combined score (P < 0.003). Subgroup exploratory analysis of 15 paired samples before and after chemotherapy showed a significant increase in cytotoxic T lymphocytes in MPM samples and PD-L1 expression in immune cells. Conclusions: TME enriched with cytotoxic T lymphocytes is associated with higher levels of macrophages and PD-L1 expression on tumor cells and with aggressive histopathological features, lower response to chemotherapy and shorter survival. The role of chemotherapy as a tumor immunogenicity inducer should be confirmed in a larger validation set.

Heterogeneous Contributing Factors in MPM Disease Development and Progression: Biological Advances and Clinical Implications.

Malignant pleural mesothelioma (MPM) tumors are remarkably aggressive and most patients only survive for 5-12 months; irrespective of stage; after primary symptoms appear. Compounding matters is that MPM remains unresponsive to conventional standards of care; including radiation and chemotherapy. Currently; instead of relying on molecular signatures and histological typing; MPM treatment options are guided by clinical stage and patient characteristics because the mechanism of carcinogenesis has not been fully elucidated; although about 80% of cases can be linked to asbestos exposure. Several molecular pathways have been implicated in the MPM tumor microenvironment; such as angiogenesis; apoptosis; cell-cycle regulation and several growth factor-related pathways predicted to be amenable to therapeutic intervention. Furthermore, the availability of genomic data has improved our understanding of the pathobiology of MPM. The MPM genomic landscape is dominated by inactivating mutations in several tumor suppressor genes; such as CDKN2A; BAP1 and NF2. Given the complex heterogeneity of the tumor microenvironment in MPM; a better understanding of the interplay between stromal; endothelial and immune cells at the molecular level is required; to chaperone the development of improved personalized therapeutics. Many recent advances at the molecular level have been reported and several exciting new treatment options are under investigation. Here; we review the challenges and the most up-to-date biological advances in MPM pertaining to the molecular pathways implicated; progress at the genomic level; immunological progression of this fatal disease; and its link with developmental cell pathways; with an emphasis on prognostic and therapeutic treatment strategies.

Heterogeneity in Immune Cell Content in Malignant Pleural Mesothelioma.

Malignant pleural mesothelioma (MPM) is a highly aggressive cancer with limited therapy options and dismal prognosis. In recent years, the role of immune cells within the tumor microenvironment (TME) has become a major area of interest. In this review, we discuss the current knowledge of heterogeneity in immune cell content and checkpoint expression in MPM in relation to prognosis and prediction of treatment efficacy. Generally, immune-suppressive cells such as M2 macrophages, myeloid-derived suppressor cells and regulatory T cells are present within the TME, with extensive heterogeneity in cell numbers. Infiltration of effector cells such as cytotoxic T cells, natural killer cells and T helper cells is commonly found, also with substantial patient to patient heterogeneity. PD-L1 expression also varied greatly (16-65%). The infiltration of immune cells in tumor and associated stroma holds key prognostic and predictive implications. As such, there is a strong rationale for thoroughly mapping the TME to better target therapy in mesothelioma. Researchers should be aware of the extensive possibilities that exist for a tumor to evade the cytotoxic killing from the immune system. Therefore, no "one size fits all" treatment is likely to be found and focus should lie on the heterogeneity of the tumors and TME.

Antitumor effect of novel anti-podoplanin antibody NZ-12 against malignant pleural mesothelioma in an orthotopic xenograft model.

Podoplanin (aggrus) is highly expressed in several types of cancers, including malignant pleural mesothelioma (MPM). Previously, we developed a rat anti-human podoplanin mAb, NZ-1, and a rat-human chimeric anti-human podoplanin antibody, NZ-8, derived from NZ-1, which induced antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity against podoplanin-positive MPM cell lines. In this study, we showed the antitumor effect of NZ-1, NZ-8, and NZ-12, a novel rat-human chimeric anti-human podoplanin antibody derived from NZ-1, in an MPM orthotopic xenograft SCID mouse model. Treatment with NZ-1 and rat NK (CD161a(+) ) cells inhibited the growth of tumors and the production of pleural effusion in NCI-H290/PDPN or NCI-H226 orthotopic xenograft mouse models. NZ-8 and human natural killer (NK) (CD56(+) ) cells also inhibited tumor growth and pleural effusion in MPM orthotopic xenograft mice. Furthermore, NZ-12 induced potent ADCC mediated by human MNC, compared with either NZ-1 or NZ-8. Antitumor effects were observed following treatment with NZ-12 and human NK (CD56(+) ) cells in MPM orthotopic xenograft mice. In addition, combined immunotherapy using the ADCC activity of NZ-12 mediated by human NK (CD56(+) ) cells with pemetrexed, led to enhanced antitumor effects in MPM orthotopic xenograft mice. These results strongly suggest that combination therapy with podoplanin-targeting immunotherapy using both NZ-12 and pemetrexed might provide an efficacious therapeutic strategy for the treatment of MPM.

Immune response profiling of malignant pleural mesothelioma for diagnostic and prognostic biomarkers.

The asbestos induced cancer malignant mesothelioma (MM) is difficult to diagnose and has a poor prognosis. MM is an immunological cancer, therefore autoantibodies may be suitable biomarkers and associated with prognosis. We used Protoarray(®) microarrays to determine immune responses to 8798 antigens in 10 MM and 10 asbestos exposed controls and developed diagnostic panels using 17 antigens from this. The AUC of these panels were independently tested in these 10 MM patients and controls and in a validation group of 36 controls and 35 MM patients using luminex assays; none of the antigens identified were validated. Immune responses to RAB38 were associated with a better prognosis.

Curative Effects of Dendritic Cells Combined with Cytokine-Induced Killer Cells in Patients with Malignant Pericardial Effusion.

BACKGROUND To determine the effects of dendritic cells (DCs) and cytokine-induced killer (CIK) cells in patients with malignant pericardial effusion. MATERIAL AND METHODS All patients underwent pericardial puncture and indwelling catheter insertion. After pericardial drainage, the 16 patients in the treatment group received an infusion of 20 mL DCs and CIK cells (>1.0×10¹° cells) and 500,000 U interleukin (IL)-2 for 3 successive days. The 15 control-group patients received 30 mg/m² cisplatin and 500,000 U IL-2 for 3 successive days. The treatment effects were assessed using imaging data. RESULTS The total efficiency and complete remission rates were higher in the treatment group than in the control group at 4 weeks (total efficiency: 87.50% vs. 73.33%; complete remission: 62.50% vs. 46.67%) and 3 months after the treatment (total efficiency: 81.25% vs. 66.67%; complete remission: 50.00% vs. 40.00%; P<0.05 for all). In both groups, the Karnofsky scores for quality of life improved after treatment. However, the curative effects were better in the treatment group than in the control group (P<0.05). The following adverse reactions occurred: fever, 6 treatment-group patients and 3 control-group patients; chest pain, 2 treatment-group patients and 7 control-group patients; gastrointestinal reactions, 1 treatment-group patient and 6 control-group patients; and bone marrow suppression, 1 treatment-group patient and 5 control-group patients. The between-group differences in adverse reactions were significant (P<0.05). CONCLUSIONS The combination of DCs and CIK cells effectively treated malignant pericardial effusion, produced few side effects, and improved the patients' quality of life.

Chylothorax as Rare Manifestation of Pleural Involvement in Waldenström Macroglobulinemia: Mechanisms and Management.

Here we report the clinical, pathological, and immunological features of a rare case of Waldenström macroglobulinemia (WM) with pleural infiltrations. An atypical chylothorax, successfully treated by videothoracoscopy, represented the main clinical feature of this case of low-grade lymphoplasmacytic lymphoma. Pleuropulmonary manifestations are rare (from 0 to 5% of cases) in WM, with chylothorax observed in just seven patients worldwide. In addition to describing this uncommon clinical presentation, we investigate hypothetical pathogenetic mechanisms causing chylothorax and through an up-todate review of available literature furnish helpful suggestions for diagnosis and management of chylothorax in WM patients.

A novel targeting therapy of malignant mesothelioma using anti-podoplanin antibody.

Podoplanin (Aggrus), which is a type I transmembrane sialomucin-like glycoprotein, is highly expressed in malignant pleural mesothelioma (MPM). We previously reported the generation of a rat anti-human podoplanin Ab, NZ-1, which inhibited podoplanin-induced platelet aggregation and hematogenous metastasis. In this study, we examined the antitumor effector functions of NZ-1 and NZ-8, a novel rat-human chimeric Ab generated from NZ-1 including Ab-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity against MPM in vitro and in vivo. Immunostaining with NZ-1 showed the expression of podoplanin in 73% (11 out of 15) of MPM cell lines and 92% (33 out of 36) of malignant mesothelioma tissues. NZ-1 could induce potent ADCC against podoplanin-positive MPM cells mediated by rat NK (CD161a(+)) cells, but not murine splenocytes or human mononuclear cells. Treatment with NZ-1 significantly reduced the growth of s.c. established tumors of MPM cells (ACC-MESO-4 or podoplanin-transfected MSTO-211H) in SCID mice, only when NZ-1 was administered with rat NK cells. In in vivo imaging, NZ-1 efficiently accumulated to xenograft of MPM, and its accumulation continued for 3 wk after systemic administration. Furthermore, NZ-8 preferentially recognized podoplanin expressing in MPM, but not in normal tissues. NZ-8 could induce higher ADCC mediated by human NK cells and complement-dependent cytotoxicity as compared with NZ-1. Treatment with NZ-8 and human NK cells significantly inhibited the growth of MPM cells in vivo. These results strongly suggest that targeting therapy to podoplanin with therapeutic Abs (i.e., NZ-8) derived from NZ-1 might be useful as a novel immunotherapy against MPM.