Malignant Mesothelioma Patients Research Articles

Overexpression of Estrogen Receptor Beta and Its Prognostic Significance among Malignant Pleural Mesothelioma Patients

Abstract Background The expression of estrogen receptor beta (ER beta) and its correlation with the prognosis of malignant mesothelioma remains controversial. This study aimed at studying ER beta expression in tumour cells in patients with mesothelioma and its association with clinicopathological factors and survival outcomes. Material and Methods A prospective study to evaluate prognostic significance of ER beta overexpression by immunohistochemistry (IHC) on paraffin blocks among malignant mesothelioma patients at Ain Shams university hospital and correlate their overexpression with the patients' follow up clinical data, OS, and PFS. Results Forty-two mesothelioma cases were enrolled and followed up, High ER beta expression (modified Allred score 7-9) was reported in 9.5% of the patients (4 cases), moderate expression (modified Allred score 4-6) was reported in 28.6% of the patients(12 cases), weak and negative expression ( modified Allred score 0-3) was reported in 61% of the patients(26 cases), percent of ER beta positive cases was 69% of the total patients, there was no statistical difference as regard age (p value:0.8), sex(p value:0.4), stage (p-value: 0.71), ECOG (p-value :0.84), histological subtype(p value:0.17) and response to first-line treatment (p value:0.5) across the 3 groups of patients (high, moderate, weak and negative ER beta on tumour cells).there was no statistically significant difference in OS and PFS for ER beta overexpression. Conclusion ER beta overexpression was not associated with improved OS or PFS in mesothelioma patients, larger sample size would be recommended for more solid conclusions.

Survival analysis of 37 cases of malignant mesothelioma

Objective: To explore the relationship between clinicopathological features, treatment and prognosis of patients with malignant mesothelioma, and provide theoretical basis for the prevention and treatment of malignant mesothelioma. Methods: In November 2022, the clinical data of 37 patients with malignant mesothelioma diagnosed in Qingdao Central Hospital from July 2014 to November 2022 were retrospectively analyzed, and the prognostic factors were analyzed by Kaplan-Meier and log-rank tests. Results: The median age of the 37 patients was 66 years old, all patients were confirmed by pathology. The median survival time of all patients was 30.00 months. The 1-year, 2-year, 3-year and 5-year cumulative survival rates were 70.27% (26/37), 48.65% (18/37), 16.22% (6/37) and 13.51% (5/37), respectively. Compared with different treatments, the median survival time of palliative care patients was 5.00 months, which was significantly lower than that of operation group (30.33 months), chemotherapy group (30.00 months), surgery combined with chemotherapy group (30.00 months) and chemotherapy combined with bevacizumab targeted therapy group (47.42 months) (P<0.05). Gender, age (≥60 years old or <60 years old), smoking history, occupational exposure history, disease site, and surgical history were not factors affecting the survival of malignant mesothelioma patients (P>0.05) . Conclusion: The clinical symptoms of malignant mesothelioma are not specific, but early initiation of treatment can still prolong survival, and chemotherapy combined with anti-vascular targeted therapy shows better therapeutic effect.

Prognostic significance of inflammation scores in malignant mesothelioma.

The relationship between inflammatory markers and survival in many cancers has been investigated previously. Inflammatory markers may also offer the possibility of predicting surveillance in patients with malignant mesothelioma. Our study seeks to enhance comprehension of how variables such as the nutritional status and inflammation indices of malignant mesothelioma patients impact the disease's progression and prognosis. This study included patients who were treated at the Erciyes University Medical Oncology Clinic between 2010 and 2022 and diagnosed with malignant mesothelioma. This is a retrospective single-center cohort study. Receiver Operating Characteristic (ROC) analysis was applied to determine the inflammation markers' optimal cut-off values with high sensitivity and specificity. Patients were categorized based on these values. The differences in overall survival (OS) and progression-free survival (PFS) between categorized groups were assessed using Log-rank curves and Kaplan-Meier tests. Multivariate analysis was performed using Cox regression analysis on statistically significant data. The relationship between inflammation markers and malignant mesothelioma survival was evaluated. There are 115 patients in this study. Pre-treatment high neutrophil to lymphocyte ratio (NLR) (HR: 1.34, 95% CI: 1.12-2.83, p=0.04), high pan-immune inflammation value (PIIV) (HR: 2.01, 95% CI: 1.32-4.79, p=0.03), and high systemic inflammation response index (SIRI) (HR: 1.34, 95% CI: 1.2-2.78, p=0.04) were associated with poor OS. Conversely, high advanced lung cancer inflammation index (ALI) (HR: 0.73, 95% CI: 0.53-0.84, p=0.03) and high hemoglobin-albumin-lymphocyte and platelet (HALP) (HR: 0.67, 95% CI: 0.23-0.78, p=0.02) were associated with favorable survival. Our study investigated the prognostic value of various inflammation markers in malignant mesothelioma patients and suggests that composite formulas like NLR, PIIV, SIRI, ALI, and HALP that incorporate CBC cells and nutritional parameters like albumin, height, and weight could more consistently and accurately predict malignant mesothelioma prognosis.

Interdisciplinary diagnostics and therapy of malignant mesothelioma

The asbestos-related malignant mesothelioma (MM) is one of the common occupational cancers in Germany with approximately 1000 new cases per year. Provided that the appropriate diagnostic criteria are fulfilled, MM can be diagnosed with high specificity from both histological and cytological specimens. However, many MM are detected cyto-/histologically only at advanced stages. Clinical/radiological aspects complement each other and enable interdisciplinary assessment of tumor stage and individualized decisions on the best possible therapeutic options. Diagnostically, video-assisted thoracoscopy (VATS) has the highest priority. Therapy planning is based on the MM subtype, tumor spread and stage, and the patient's clinical condition. MM has generally a very unfavorable prognosis. Accordingly, the standard therapy aims at a macroscopic radical tumor resection in terms of cytoreduction within the framework of a suitable multimodal therapy concept (chemotherapy, radiotherapy, psychooncology). The aim of palliative measures should be primarily symptom control. Overall, interdisciplinary diagnosis and therapy of MM is crucial for the best possible care of MM patients.

Serum Calretinin and Genetic Variability as a Prognostic and Predictive Factor in Malignant Mesothelioma.

Calretinin is a promising diagnostic biomarker for malignant mesothelioma (MM), but less is known about its prognostic role. Our aim was to evaluate the association between serum calretinin concentration or genetic factors and the survival or outcome of cisplatin-based chemotherapy in MM. Our study included 265 MM patients. Serum calretinin concentration was determined using ELISA. Patients were genotyped for seven polymorphisms in CALB2, E2F2, MIR335, NRF1, and SEPTIN7 using competitive allele-specific PCR. Nonparametric tests, logistic regression, and survival analysis were used for statistical analysis. Higher serum calretinin concentration was associated with shorter progression-free (PFS) (HR = 1.18 (1.02-1.37), p = 0.023) and overall survival (OS) (HR = 1.20 (1.03-1.41), p = 0.023), but the association was not significant after adjusting for clinical factors (HR = 1.05 (0.85-1.31), p = 0.653 and HR = 1.06 (0.84-1.34), p = 0.613, respectively). SEPTIN7 rs3801339 and MIR335 rs3807348 were associated with survival even after adjustment (HR = 1.76 (1.17-2.64), p = 0.007 and HR = 0.65 (0.45-0.95), p = 0.028, respectively). Calretinin concentration was higher in patients who progressed after treatment with cisplatin-based chemotherapy (1.68 vs. 0.45 ng/mL, p = 0.001). Calretinin concentration above 0.89 ng/mL was associated with shorter PFS and OS from the start of chemotherapy (HR = 1.88 (1.28-2.77), p = 0.001 and HR = 1.91 (1.22-2.97), p = 0.004, respectively), even after adjusting for clinical factors (p < 0.05). MIR335 rs3807348 was associated with a better response to chemotherapy (OR = 2.69 (1.17-6.18), p = 0.020). We showed that serum calretinin is associated with survival and chemotherapy treatment outcomes in MM and could serve as a predictive biomarker.

A postmortem case control study of asbestos burden in lungs of malignant mesothelioma cases

BackgroundAsbestos lung content is regarded as the most reliable tool for causal attribution of malignant mesothelioma (MM) to previous asbestos exposures. However, there is a lack of studies on asbestos burden in lungs of MM patients in comparison with healthy individuals. This study aims to provide such a comparison, investigating, as well, differences in asbestos lung burden with sex and time trends.MethodsAsbestos lung content has been assessed on formalin-fixed lung fragments using scanning electron microscopy coupled with energy dispersion spectroscopy (SEM–EDS) on individuals deceased from MM (cases) and healthy subjects without any lung disease who died from violent causes (controls) between 2005 and 2023.ResultsAsbestos and asbestos bodies (ABs) were found, respectively, in 73.7% and 43.2% of cases and in 28 and 22% of controls; in MM cases the most represented asbestos types were crocidolite and amosite, whereas in controls it was tremolite-actinolite asbestos. The concentration of both asbestos fibers and ABs was statistically significantly higher in MM cases compared to controls. The mean asbestos fibers width was also significantly higher in cases than controls. Males and females with MM showed similar asbestos and ABs concentrations, but females had higher concentrations of chrysotile, and significantly lower fibers width compared to males. Time trends show that MM lung asbestos concentrations decreased starting in 2011.DiscussionThe results suggest a correlation between asbestos burden in lungs and MM risk. The different concentration of chrysotile, as well as the different width of asbestos fibers in MM males and females might reflect a sex difference in response of the lung microenvironment to inhaled asbestos. Finally, this study provides the first pathological evidence of the effect of the ban of asbestos use, demonstrating a significant decrease of asbestos lung content after 2011.

The association of genetic factors with serum calretinin levels in asbestos-related diseases.

Asbestos exposure is associated with different asbestos-related diseases, including malignant mesothelioma (MM). MM diagnosis is confirmed with immunohistochemical analysis of several markers, including calretinin. Increased circulating calretinin was also observed in MM. The aim of the study was to determine if CALB2 polymorphisms or polymorphisms in genes that can regulate calretinin expression are associated with serum calretinin levels or MM susceptibility. The study included 288 MM patients and 616 occupationally asbestos-exposed subjects without MM (153 with asbestosis, 380 with pleural plaques and 83 without asbestos-related disease). Subjects were genotyped for seven polymorphisms in CALB2, E2F2, MIR335, NRF1 and SEPTIN7 genes using competitive allele-specific polymerase chain reaction (PCR). Serum calretinin was determined with ELISA in 545 subjects. Nonparametric tests, logistic regression and receiver operating characteristic (ROC) curve analysis were used for statistical analysis. Carriers of at least one polymorphic CALB2 rs889704 allele had lower calretinin levels (P = 0.036). Carriers of two polymorphic MIR335 rs3807348 alleles had higher calretinin (P = 0.027), while carriers of at least one polymorphic NRF1 rs13241028 allele had lower calretinin levels (P = 0.034) in subjects without MM. Carriers of two polymorphic E2F2 rs2075995 alleles were less likely to develop MM (odds ratio [OR] = 0.64, 95% confidence interval [CI] = 0.43-0.96, P = 0.032), but the association was no longer significant after adjustment for age (P = 0.093). Optimal serum calretinin cut-off values differentiating MM patients from other subjects differed according to CALB2, NRF1, E2F2, and MIR335 genotypes. The results of presented study suggest that genetic variability could influence serum calretinin levels. These findings could contribute to a better understanding of calretinin regulation and potentially to earlier MM diagnosis.

Impact of Perioperative Systemic Chemotherapy on Survival for Patients Who have Diffuse Malignant Peritoneal Mesothelioma Treated with CRS-HIPEC.

The available data on the role of perioperative systemic chemotherapy (SC) for diffuse malignant peritoneal mesothelioma (DMPM) patients undergoing (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) is heterogeneous and unstandardized. This study aimed to evaluate the impact of SC on the survival outcomes of DMPM patients undergoing CRS-HIPEC and to identify prognostic factors that affect the decision to administer SC. Patients who underwent CRS-HIPEC in the National Cancer Institute Milan (1995-2020) were retrospectively analyzed using propensity score-matching of known covariates. The patients were grouped into three groups: group A (neoadjuvant chemotherapy [NACT] and no-SC), group B (no-SC and adjuvant chemotherapy [ACT]), and group C (NACT and ACT). Overall survival (OS) and progression-free survival (PFS) were calculated using the Kaplan-Meir method, and prognostic factors were calculated using the Cox-regression method. After a median follow-up period of 45 months (95% confidence interval [CI], 6.348-83.652 months) for group A, 115 months (95% CI, 44.379-185.621 months) for group B, and 88 months (95% CI, 3.296-172.704 months) for group C, the study analyzed 154 DMPM patients consisting of matched group A (NACT: 60 + no-SC: 52 = 112), group B (ACT: 38 + no-SC: 38 = 76), and group C (NACT: 31 + ACT: 31 = 62). The patients undergoing ACT had better 5-year OS and PFS than the patients undergoing NACT. In the multivariate analysis, ACT was significantly associated with improved OS by 48% (hazard ratio [HR], 0.52; 95% CI, 0.280-0.965, p = 0.038). For PFS, the association of ACT did not reach statistical significance (HR, 0.531; 95% CI, 0.266-1.058; p = 0.072). The optimum treatment sequence for DMPM is CRS-HIPEC followed by adjuvant chemotherapy for high-risk patients. Upfront surgery appears preferable to NACT for patients amenable to complete CRS.

Mesothelin expression remodeled the immune-matrix tumor microenvironment predicting the risk of death in patients with malignant pleural mesothelioma.

The combination of immunobiological agents with immune checkpoint proteins is a promising treatment for malignant pleural mesothelioma (MPM). Mesothelin and anti-PD-L1 antibody-drug conjugates specifically target malignant neoplastic cells, inhibit the migration and invasion of neoplastic cells, and restore the immune landscape. In this study, we confirmed the importance of mesothelin and examined the relationship between mesothelin and the immune landscape of the tumor microenvironment (TME) in two MPM cohorts. The discovery cohort included 82 MPM cases. Tissue microarray slides were generated, and samples were processed for hematoxylin & eosin staining, immunohistochemistry, and immunofluorescence assays. The relationship between mesothelin, biomarkers of histogenesis, histological aggressiveness, PD-L1, immune cells (CD4, CD8, CD20, CD68), and collagen type I and type V fibers was evaluated by quantitative digital analyses. The outcome was the survival time until death from disease recurrence. The exploratory cohort included 87 malignant mesothelioma (MESO) patients from The Cancer Genome Atlas database. Most patients were male (70.7%) with a history of asbestos exposure (53.7%) and with the epithelioid subtype (89%). Surgical resection was performed in 85.4% of patients, and 14.6% received chemotherapy; 59.8% of patients died from disease extension to the mediastinum. Low tumor mesothelin expression was associated with tumor necrosis and nuclear grade 1, whereas high mesothelin expression was significantly associated with the epithelioid histotype and high density of T cells CD8+, macrophages CD68+, and collagen type I fibers. Cox multivariate analysis showed a high risk of death for non-operated patients [hazard ratio (HR), 3.42 (1.15-10.16)] with low tumor mesothelin levels [HR, 2.58 (1.09-6.10)] and high PD-L1 and low infiltration of T cells CD4+ [HR, 3.81 (1.58-9.18)]. In the exploratory cohort, low mesothelin and high COL1A1 and COL5A1 expression were associated with poor overall survival. Tumor mesothelin expression associated with the TME immune landscape predicts the risk of death for patients with MPM and could be a new target for immunotherapy in MPM.

Establishment of a Bayesian network model to predict the survival of malignant peritoneal mesothelioma patients after cytoreductive surgery plus hyperthermic intraperitoneal chemotherapy

Objectives To establish a Bayesian network (BN) model to predict the survival of patients with malignant peritoneal mesothelioma (MPM) treated with cytoreductive surgery (CRS) plus hyperthermic intraperitoneal chemotherapy (HIPEC). Methods The clinicopathological data of 154 MPM patients treated with CRS + HIPEC at our hospital from April 2015 to November 2022 were retrospectively analyzed. They were randomly divided into two groups in a 7:3 ratio. Survival analysis was conducted on the training set and a BN model was established. The accuracy of the model was validated using a confusion matrix of the testing set. The receiver operating characteristic (ROC) curve and area under the curve were used to evaluate the overall performance of the BN model. Results Survival analysis of 107 patients (69.5%) in the training set found ten factors affecting patient prognosis: age, Karnofsky performance score, surgical history, ascites volume, peritoneal cancer index, organ resections, red blood cell transfusion, pathological types, lymphatic metastasis, and Ki-67 index (all p < 0.05). The BN model was successfully established after the above factors were included, and the BN model structure was adjusted according to previous research and clinical experience. The results of confusion matrix obtained by internal validation of 47 cases in the testing set showed that the accuracy of BN model was 72.7%, and the area under ROC was 0.74. Conclusions The BN model was established successfully with good overall performance and can be used as a clinical decision reference.

Association of tertiary lymphoid structures with outcomes from PD-1 inhibition in advanced malignant pleural mesothelioma.

e20545 Background: Predictive biomarkers of benefit form immunotherapy in malignant mesothelioma patients remain poorly defined. The 9-15 PROMISE-MESO study (NCT02991482) of the European Thoracic Oncology Platform (ETOP) evaluated second-line pembrolizumab against chemotherapy. Pembrolizumab led to an increased response rate compared to chemotherapy, which did not translate to survival benefits. We evaluated if the presence of tertiary lymphoid structures (TLSs) with different compositions or LRRC15+ immune suppressive fibroblasts could predict the clinical benefit from pembrolizumab. Methods: We performed multiplex immune histochemistry analysis on tumor tissues. 144 patients were included in the clinical trial, from whom, 112 had available tumor tissue for analysis: 55 patients in the chemotherapy arm, and 57 patients in the immune therapy arm. We performed the following panel: calretinin or WT1 (mesothelioma cells), CD20, CD23, CD11c, LRRC15, aSMA, and DAPI. We used the Akoya Vectra Polaris platform for analysis. The IFQuant analytical pipeline developed at the Swiss Institute for Bioinformatics (SIB) was used for analyses. Results: We defined three categories of TLSs: general CD20+ TLSs independent of other markers. CD20/CD23 double-positive as mature TLSs (mTLS), and TLSs with dendritic cells (CD11c+, cTLS). Immune suppressive CAFs were defined as LRRC15+ cells/mm2. CD20+ TLSs were identified in 84% of patients' stroma, with a median of 21 TLSs/tumor tissue and 2 TLSs/mm2. mTLSs were rare, only detected in 10 of the 112 patients (9%). cTLSs with dendritic cells were more frequent and present in 45% of all patients (50/112), and roughly half of the TLS+ patients (53%) had CD11c+ cells detected in TLSs. LRRC15+ cancer-associated fibroblasts (CAFs) were detected in 85% of patients, with a median density of 61 cells/mm2. LRRC15- tumors also contained TLSs but had significantly fewer than LRRC15+ tumors (p = 0.0079). We did not find any significant association between the responses or PFS with TLS, mTLS, and LRRC15+ CAFs. We found inverse association between cTLS levels and response to immune therapy (p = 0.037) but not for PFS. Conclusions: Our data shows that advanced malignant mesotheliomas frequently harbor TLSs, but these TLSs are mostly not activated/mature. The absence of antigen-presenting cells in TLSs, like CD11c dendritic cells, is unexpectedly associated with increased response to pembrolizumab. The high prevalence of immune suppressive LRRC15+ CAFs might explain the low response rate to pembrolizumab and could be linked to the absence of maturation of TLSs. Clinical trial information: EudraCT number: 2016-002062-31 .

Cytopathological characterization of ascites for the diagnosis of serous ovarian carcinoma

Objective: To investigate the cytomorphological and immunocytochemical features of tumor cells in the ascites of ovarian plasmacytoma (SOC). Methods: Specimens of serous cavity effusions were collected from 61 tumor patients admitted to the Affiliated Wuxi People's Hospital of Nanjing Medical University from January 2015 to July 2021, including ascites from 32 SOC, 10 gastrointestinal adenocarcinomas, 5 pancreatic ductal adenocarcinomas, 6 lung adenocarcinomas, 4 benign mesothelial hyperplasia and 1 malignant mesothelioma patients, pleural effusions from 2 malignant mesothelioma patients and pericardial effusion from 1 malignant mesothelioma. Serous cavity effusion samples of all patients were collected, conventional smears were made through centrifugation, and cell paraffin blocks were made through centrifugation of remaining effusion samples. Conventional HE staining and immunocytochemical staining were applied to observe and summarize cytomorphological characteristics and immunocytochemical characteristics. The levels of serum tumor markers carbohydrate antigen 125 (CA125), carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9) were detected. Results: Of the 32 SOC patients, 5 had low-grade serous ovarian carcinoma (LGSOC) and 27 had high-grade serous ovarian carcinoma (HGSOC). 29 (90.6%) SOC patients had elevated serum CA125, but the difference was not statistically significant between them and patients with non-ovarian primary lesions included in the study (P>0.05); The serum CEA was positive in 9 patients with gastrointestinal adenocarcinoma and 5 patients with lung adenocarcinoma, and the positive rate was higher than that in SOC patients (P<0.001); The serum CA19-9 was positive in 5 patients with gastrointestinal adenocarcinoma and 5 patients with pancreatic ductal adenocarcinoma, and the positive rate was higher than that in SOC patients (P<0.05). The serum CA125, CEA and CA19-9 were within the normal range in 4 patients with benign mesothelial hyperplasia. LGSOC tumor cells were less heterogeneous and aggregated into small clusters or papillary pattern, and psammoma bodies could be observed in some LGSOC cases. The background cells were fewer and lymphocytes were predominant; the papillary structure was more obvious after making cell wax blocks. HGSOC tumor cells were highly heterogeneous, with significantly enlarged nuclei and varying sizes, which could be more than 3-fold different, and nucleoli and nuclear schizophrenia could be observed in some cases; tumor cells were mostly clustered into nested clusters, papillae and prune shapes; there were more background cells, mainly histiocytes. Immunocytochemical staining showed that AE1/AE3, CK7, PAX-8, CA125, and WT1 were diffusely positively expressed in 32 SOC cases. P53 was focally positive in all 5 LGSOCs, diffusely positive in 23 HGSOCs, and negative in the other 4 HGSOCs. Most of adenocarcinomas of the gastrointestinal tract and lung had a history of surgery, and tumor cells of pancreatic ductal adenocarcinoma tend to form small cell nests. Immunocytochemistry can assist in the differential diagnosis of mesothelial-derived lesions with characteristic "open window" phenomenon. Conclusion: Combining the clinical manifestations of the patient, the morphological characteristics of the cells in the smear and cell block of the ascites can provide important clues for the diagnosis of SOC, and the immunocytochemical tests can further improve the accuracy of the diagnosis.

Preliminary validation of a brief PROM assessing psychological distress in patients with malignant mesothelioma: The mesothelioma psychological distress tool-Patients.

Psychological suffering in malignant mesothelioma (MM) differs from that in other cancers because of its occupational etiology, and we aimed to develop specific patient-reported outcome measures to assess it. We used a multi-method prospective observational multicentric study (N = 149), and a preliminary questionnaire validation was performed through a Bayesian approach. Item analysis showed a good internal consistency and reliability (Cronbach alpha = 0.79 [95% CI = 0.74-0.93]. Twenty of the 41 initial items were selected as posterior 95% highest density interval factor loading standardized effect size fell outside of the region of practical equivalence. Bayesian exploratory factor analysis showed a two-factor structure: (1) Trauma-related reactions (TR, 13 items) and (2) Claim for justice (CJ, 7 items), confirmed by the Bayesian confirmatory factor analysis. Latent factors were poorly correlated (Posterior median: 0.13; 95% CI = -0.079 to 0.323). The 90% root mean square error of approximation posterior median was 0.04 [90% CI = 0.03-0.58]; the 90% chi-square posterior median was 242 [90% CI = 209-287]. Psychological suffering in MM patients implies negative cognitive, emotional, and somatic reactions related to the traumatic impact of the disease and the need to obtain justice through economic compensation. Our findings provide preliminary evidence that the Mesothelioma Psychological Distress Tool-Patients could be a promising and reliable instrument to assess MM patients' psychological distress.

1661MO Genomic somatic copy number alterations drive adaptive tumor immune suppression and primary resistance to anti-PD1 + anti-angiogenics in pleural mesothelioma

In patients with advanced pleural malignant mesothelioma (MM), Pembrolizumab [P] in combination with Nintedanib [N] synergize with a response rate of 24% (PEMBIB trial initial results reported at ESMO Congress 2021), superior to [P] alone (8% in MM in the KN158 trial). Here we report new data from the biomarker analysis performed in this trial (NCT02856425). 30 MM patients were treated with [N] (150mg bid) & [P] (200mg IV Q3W). Fresh tumor biopsies were collected in media and immediately processed at baseline and at C2D1 for measuring proteins released in the biopsy supernatant and immune cell infiltrates (by Flow Cytometry). Frozen and fixed tumor biopsies were also analyzed by WES, FISH, RNAseq and IHC. Circulating cytokines & immune cells were measured on plasma and fresh whole blood at baseline and on-treatment. At 6 months, patients remaining in stable disease or objective tumor response per RECIST1.1 were categorized as having Durable Clinical Benefit (DCB). All differences reported here are statistically significant with a p value at least <0,05. Higher PD-L1 on tumor cells, higher tumor CD45+, CD3+ & CD8+ T-cells characterized the DCB group at baseline. Unexpectedly, active recruitment of CD8+ T-cells, with higher gene expression of EOMES, T-BET, IFNg, & GzmB, occurred in No DCB tumors upon treatment. At C2D1, same levels of tumor infiltrating CD8+ T-cells were found in DCB & No DCB tumors. This tumor T-cell recruitment occurred in a context of high blood and tumor CXCL9 increases upon [N]+[P] treatment. However, No DCB patients presented more IL6, VEGF, IL8, in their blood & tumor secretome and they increased their tumor content in CD4+ CD25+ Tregs compared to DCB patients upon treatment. Tumor somatic copy number alterations (SCNA) were higher in tumors with no DCB and correlated with higher plasmatic IL-6 rate levels in MM patients. MM primary resistance to anti-PD1+antiangiogenics is not due to a lack of CD8+ T-cell tumor response but to an adaptive secretion of IL6 by tumors, driven by genomic SCNA, leading to VEGF and IL8 secretion, and recruitment of tumor infiltrating Tregs.

P034 Checkpoint inhibitor-induced coexisting myositis and myasthenia gravis in a malignant mesothelioma patient: a case report

Abstract Background/Aims Nivolumab &amp; ipilimumab are immune checkpoint inhibitors (ICIs) and combination therapy has shown efficacy in patients with malignant pleural mesothelioma. Nivolumab is a fully human IgG4 monoclonal antibody known as a programmed cell death 1 (PD-1) immune checkpoint inhibitor. The combination therapy nivolumab &amp; ipilimumab features a potentially synergistic mechanism of action that targets 2 different checkpoints (PD-1 and CTLA-4) respectively. Myositis, an immune-related adverse event, has been reported in the literature. Ipilimumab and nivolumab have also been associated with the development/exacerbation of myasthenia gravis (MG). Methods A 75-year-old woman with right sarcomatoid malignant mesothelioma presented to the hospital with muscle cramps and a raised creatinine kinase, a few weeks after initiation of nivolumab &amp; ipilimumab. In addition to myalgia and proximal limb weakness, her symptoms progressed to involve new right eye ptosis, double vision, and dysphagia. She was diagnosed with ICI-related myositis after an EMG was suggestive of myositis, but antibody screens for myositis and myasthenia gravis were negative. Treatment was started with intravenous methylprednisolone and subsequently was treated with IVIG and mycophenolate mofetil 1g twice daily alongside the tapering oral steroids for maintenance, leading to resolution of proximal muscle weakness caused by immunotherapy-induced myositis. Following the initial improvement of muscle weakness, reassessment revealed worsening bulbar symptoms including ptosis, dysphagia, and diplopia. She was therefore readmitted. As her creatinine kinase, muscle weakness and CRP had now normalized, the impression at this stage was of symptoms predominantly related to myasthenia gravis rather than of myositis flare-up. Pyridostigmine was commenced as a trial, which demonstrated improvement with regards to the ptosis. Results ICIs have led to the development of new approaches for cancer treatment with positive outcomes. However, checkpoint blockade is associated with a unique spectrum of immune-related adverse events, which may cause irreversible neurological deficits and even death. This is a rare reported case of a patient developing nivolumab &amp; ipilimumab-induced myositis concomitant with new-onset MG after treatment for advanced mesothelioma. Additional studies are needed to explore the association between myositis, MG, and ICI therapy. This woman is having ongoing multidisciplinary management involving oncologists, rheumatologists, and neurologists. She continues to be treated with mycophenolate mofetil and pyridostigmine. Ipilimumab and nivolumab were permanently discontinued. Conclusion This case demonstrates that rheumatologists must be alert to the possibility of myositis overlapping with MG in patients treated with checkpoint inhibitors who develop weakness. Early recognition complete evaluation and a team approach are essential in such a complex case. Disclosure F. Javaid: None. S. Byravan: None. S. Makan: None. M. Kadicheeni: None. R. Neame: None. M. Durrani: None.

What has changed in malignant mesothelioma between 1990 and 2019? A time- series analyses in Turkey.

To investigate the changes in epidemiological and survival characteristics of malignant mesothelioma (MM) cases diagnosed in a 30-year period between 1990 and 2019. Data were analyzed considering three time periods (1990-1999, 2000-2009, 2010-2019) when treatment practices changed. The Join point Regression Program was used to analyze the change in clinical and epidemiological characteristics of the cases. Kaplan-Meier analysis was used to calculate the overall survival of the patients. Cox regression analysis was used to determine the effect of variables on survival. The study group consisted of 928 MM patients. During the study period, the mean age of the patients and the percentage of epithelioid subtype increased, while the percentage of female and histopathologically unidentified cases decreased. The median survival (95%CI) of patients according to the study periods was 9.0 (7.2-10.9), 9.0 (7.6-10.4) and 12.0 (10.5-13.5) months, respectively. A significant increase in overall survival was observed in the time trend (p = 0.013). There was no significant change in overall survival in patients receiving best supportive care over the 30-year period (p = 0.060), but an improvement of 1.4 (95%CI 0.2 to 2.7) months (p = 0.027) was observed in patient receiving chemotherapy. An improvement in overall survival of 4.8 (1.2 to 8.4) months was also observed in patients receiving multimodality treatment during 2000-2019 (p = 0.014). MM patients who were younger, female, diagnosed after 2000, epithelioid subtype, early stage, and received chemotherapy or multimodal treatment had longer survival. It was found that histopathological diagnosis and treatment success in MM have improved over the years.

Correlation of MET-Receptor Overexpression with MET Gene Amplification and Patient Outcome in Malignant Mesothelioma.

Thanks to clinically newly introduced inhibitors of the mesenchymal–epithelial transition (MET) receptor tyrosine-kinase, MET-gene copy number gain/amplification (MET-GCNG/GA) and increased expression of the MET protein are considered very promising therapeutic targets in lung cancer and other malignancies. However, to which extent these MET alterations occur in malignant mesothelioma (MM) remains unclear. Thus, we investigated by well-established immunohistochemistry and fluorescence in situ hybridization methods, the frequency of these alterations in specimens from 155 consecutive MMs of different subtypes obtained from pleural or peritoneal biopsies and pleurectomies. Thirty-three benign reactive mesothelial proliferations (RMPs) were used as controls. MET-protein upregulation was observed in 35% of all MM-cases, though restricted to predominantly epithelioid MMs. We detected low-/intermediate-level MET-GCNG/GA in 22.2% of MET-overexpressing MMs (7.8% of whole MM-cohort) and no MET-GCNG/GA in the other 77.8%, suggesting other upregulating mechanisms. In contrast, 100% of RMPs exhibited no MET-upregulation or MET-GCNG/-GA. Neither MET exon 14 skipping mutations nor MET-fusions were detected as mechanisms of MET overexpression in MM using RNA next-generation sequencing. Finally, in two cohorts of 30 MM patients with or without MET overexpression (MET-positive/-negative) that were matched for several variables and received the same standard chemotherapy, the MET-positive cases showed a significantly lower response rate, but no significant difference in progression-free or overall survival. Our results imply that MET overexpression occurs in a substantial fraction of predominantly epithelioid MMs, but correlates poorly with MET-amplification status, and may impact the likelihood of response to mesothelioma standard chemotherapy. The predictive significance of MET-IHC and -FISH for possible MET-targeted therapy of MM remains to be elucidated.

Diagnostic and Prognostic Value of Three microRNAs in Environmental Asbestiform Fibers-Associated Malignant Mesothelioma.

Fluoro-edenite (FE) is an asbestiform fiber identified in Biancavilla (Sicily, Italy). Environmental exposure to FE has been associated with a higher incidence of malignant mesothelioma (MM). The present study aimed to validate the predicted diagnostic significance of hsa-miR-323a-3p, hsa-miR-101-3p, and hsa-miR-20b-5p on a subset of MM patients exposed to FE and matched with healthy controls. For this purpose, MM tissues vs. nonmalignant pleura tissues were analyzed through droplet digital PCR (ddPCR) to evaluate differences in the expression levels of the selected miRNAs and their MM diagnostic potential. In addition, further computational analysis has been performed to establish the correlation of these miRNAs with the available online asbestos exposure data and clinic-pathological parameters to verify the potential role of these miRNAs as prognostic tools. ddPCR results showed that the three analyzed miRNAs were significantly down-regulated in MM cases vs. controls. Receiver operating characteristic (ROC) analysis revealed high specificity and sensitivity rates for both hsa-miR-323a-3p and hsa-miR-20b-5p, which thus acquire a diagnostic value for MM. In silico results showed a potential prognostic role of hsa-miR-101-3p due to a significant association of its higher expression and increased overall survival (OS) of MM patients.

Serum Calretinin as a Biomarker in Malignant Mesothelioma.

The early diagnosis of malignant mesothelioma (MM) could improve the prognosis of MM patients. To confirm an MM diagnosis, an immunohistochemical analysis of several tumor tissue markers, including calretinin, is currently required. Our aim is to evaluate serum calretinin as a potential biomarker in asbestos-related diseases, especially in MM. Our study includes 549 subjects: 164 MM patients, 117 subjects with asbestosis, 195 subjects with pleural plaques and 73 occupationally asbestos-exposed subjects without asbestos-related diseases. The serum calretinin concentration was determined with a commercially available enzyme immunoassay. Data on the soluble mesothelin-related peptides (SMRP) concentration are available from previous studies. MM patients had a significantly higher calretinin concentration than subjects without disease, subjects with pleural plaques or subjects with asbestosis (all p < 0.001). The histological type was significantly associated with serum calretinin: patients with sarcomatoid MM had lower calretinin than patients with the epithelioid type (p = 0.001). In a ROC curve analysis, the area under the curve for calretinin concentration predicting MM was 0.826 (95% CI = 0.782–0.869; p < 0.001). At the cutoff value of 0.32 ng/mL, sensitivity was 0.683, while specificity was 0.886. The combination of calretinin and SMRP had the highest predictive value. Calretinin is a useful biomarker that can distinguish MM from other asbestos-related diseases and could, therefore, contribute to an earlier non-invasive diagnosis of MM.

Survival of Korean Patients with Malignant Pleural Mesothelioma Compensated for the Asbestos Injury Relief

Background: The purpose of this study was to identify the epidemiologic characteristics and prognostic factors for malignant pleural mesothelioma in Korea, which are currently insufficient. The data were derived from malignant mesothelioma patients who registered under the Asbestos Injury Relief Act; Methods: A total of 728 patients received compensation from the Asbestos Injury Relief Act due to malignant mesothelioma between 2011 and 2015. Of these, 313 patients (43.0%) with malignant pleural mesothelioma were included in the study. The study variables were sex (male, female), age at diagnosis (&lt;59, 60–69, ≥70), smoking history (yes, no), surgery (yes, no), chemotherapy (yes, no), occupational exposure to asbestos (yes, no), and histological subtype (epithelioid, nonepithelioid); Results: Median survival of mesothelioma was 8.0 months (95% confidence interval: 6.2 to 9.8). The 1-year, 2-year, and 5-year survival rates (%) were 43.5%, 23.6%, and 12.5%, respectively. In multivariate analysis of Cox’s proportional hazards model; sex, age, smoking history, occupational asbestos exposure, and histological subtype were not significant prognostic factors, but surgery and chemotherapy combined was a significant predictor; Conclusions: Although the representativeness of these data is limited, our study estimates the epidemiologic characteristics of malignant pleural mesothelioma. Non-occupational exposure had a similar prognosis to occupational asbestos exposure, and there was no sex difference. In addition, it was found that receiving a combination of surgery and chemotherapy affects the survival rate, but there is a limitation in that factors such as performance status, comorbidities, and stage that contribute to survival are not considered.