Cases Of Malignant Pleural Mesothelioma Research Articles

P37.02 Improving Outcomes in Malignant Pleural Mesothelioma in an Integrated Health System

Malignant pleural mesothelioma (MPM) is a rare and aggressive tumor with an associated poor prognosis, median overall survival (OS) is 1 year, despite advances in treatment practices.1-4 NCCN guidelines recommend patients with MPM should be managed by a multidisciplinary team with experience in MPM management.5 Although there is no agreement on which surgical intervention is best,6-8 guidelines are consistent in recommending that surgeries be performed by skilled surgeons at high-volume centers.1 Improved outcomes due to regionalization of surgeries for patients with NSCLC has been demonstrated,9 but further evaluation of centralization of MPM surgeries has yet to be determined. Electronic medical records of 369 adult patients with MPM from 1/1/2009 to 12/31/2020 were reviewed and compared before (2009-2014) and after (2015-2020) MPM surgeries were regionalized to specialized surgeons and multidisciplinary review of MPM patient treatment options. We used the Kaplan-Meier method and log-rank tests to compare survival rates by period, by treatment type, and by stage. Patients were followed from cancer diagnosis date until they died or end of study follow-up, whichever occurred first. We also conducted Cox proportional hazards regression model to examine the overall survival with adjustments for age, gender, histology, stage, and Charlson Comorbidity Index (CCI). Despite similar staging, more patients received any MPM directed treatment from 2015-2020 (n=127, 65%) compared with those patients from 2009-2014 (n=77, 45%) (p<0.0001). Specifically, there was an increase in patients who received pleurectomy/decortication (PD) from 2015-2020 (n=42, 21%) compared to those who received PD in 2009-2014 (n=6, 3.5%) (p=0.0001). Median survival in patients who received multi-modality treatment (surgery, systemic therapy, +/- radiation) during 2009-2014 was 16.7 months (95% confidence interval (CI), 10.8-34.8) compared to 5.7 months (95% CI, 4.0-9.2) in patients who received no treatment. From 2015-2020, median OS for patients who received multi-modality therapy was 23.5 months compared to median survival of 4.3 months in those who received no treatment. Landmark analysis showed a significant survival benefit in patients with early stage MPM from 2015-2020 compared to the 2009-2014 cohort with a median OS 20.7 months and 12.8 months, respectively (HR, 1.58; 95% CI, 1.01-2.47; p = 0.042) (Figure 1); while patients with advanced stage MPM showed no difference in survival between 2009-2014 and 2015-2020 cohorts (HR, 0.97; 95% CI, 0.71-1.32). Consolidating mesothelioma surgery to specialized surgeons and regular multidisciplinary review of MPM cases to determine appropriate multimodality therapy improves OS in patients with MPM.

Short 57 kb CDKN2A FISH probe effectively detects short homozygous deletion of the 9p21 locus in malignant pleural mesothelioma.

Homozygous deletion (homo-d) of the cyclin-dependent kinase inhibitor 2A (CDKN2A) gene is frequently found in malignant pleural mesothelioma (MPM). Fluorescence in situ hybridization (FISH) is commonly used to detect chromosomal deletion, and sometimes reveals more frequent heterozygous deletion (hetero-d) compared with homo-d. In clinical practice, such CDKN2A FISH results belong to the 'borderline' homo-d rate, which makes it difficult to definitively diagnose MPM. Microdeletion, [<200 kilobase (kb)], can induce a 'pseudo' hetero-d signal in FISH assays with long probes owing to redundant probe reactivity. Thus, the present study hypothesized that shorter FISH probes can effectively detect the small deletion status of the CDKN2A gene and increase homo-d rate in MPM, which has high hetero-d and low homo-d status. The present study aimed to evaluate the effectiveness of a shorter CDKN2A FISH probe in diagnosing MPM. CDKN2A FISH with either a 222 kb long probe (L-probe) or a 57 kb short probe (S-probe) was performed in four MPM cases with high hetero-d and low homo-d patterns. Furthermore, immunohistochemistry for methylthioadenosine phosphorylase (MTAP) and quantitative (q)PCR analyses were performed to confirm the microdeletion of the 9p21 locus. The results demonstrated that all four MPM cases retained MTAP protein expression. CDKN2A FISH with L-probe revealed high hetero-d (cases 1-4; 73.3, 37.1, 59.2 and 64.8%, respectively) and low homo-d (cases 1-4; 12.1, 12.4, 25.4 and 22.2%, respectively). CDKN2A FISH with S-probe revealed high homo-d (cases 1-4; 96.8, 90.0, 87.5 and 82.6%, respectively), with low hetero-d (cases 1-4; 0.0, 1.2, 1.2 and 4.3%, respectively). qPCR analysis demonstrated no allele deletions of the MTAP gene and two-allele deletions of the CDKN2A gene in 3/4 cases. Taken together, these results suggest that the S-probe detects the short homo-d of the 9p21 locus more effectively than the L-probe in MPM. This can assist in solving diagnostic difficulties in cases involving high hetero-d with low homo-d.

Effect of Asbestos Consumption on Malignant Pleural Mesothelioma in Italy: Forecasts of Mortality up to 2040.

Simple SummaryAsbestos consumption figures could be used to construct epidemiological models to forecast the pleural mesothelioma mortality, although they are not frequently taken into consideration in this kind of analysis. Our purpose is to predict the future burden of pleural mesothelioma deaths in Italy until 2039 and to describe the exposure–response curve considering time lasted from the exposure start. Our results could be of interest to plan future needs of the Italian health system and to provide evidence on the consequences of asbestos exposures useful for countries in which this material is, at present, still used for productive activities.Statistical models used to forecast malignant pleural mesothelioma (MPM) trends often do not take into account historical asbestos consumption, possibly resulting in less accurate predictions of the future MPM death toll. We used the distributed lag non-linear model (DLNM) approach to predict future MPM cases in Italy until 2040, based on past asbestos consumption figures. Analyses were conducted using data on male MPM deaths (1970–2014) and annual asbestos consumption using data on domestic production, importation, and exportation. According to our model, the peak of MPM deaths is expected to occur in 2021 (1122 expected cases), with a subsequent decrease in mortality (344 MPM deaths in 2039). The exposure–response curve shows that relative risk (RR) of MPM increased almost linearly for lower levels of exposure but flattened at higher levels. The lag-specific RR grew until 30 years since exposure and decreased thereafter, suggesting that the most relevant contributions to the risk come from exposures which occurred 20–40 years before death. Our results show that the Italian MPM epidemic is approaching its peak and underline that the association between temporal trends of MPM and time since exposure to asbestos is not monotonic, suggesting a lesser role of remote exposures in the development of MPM than previously assumed.

Tumor Immune Microenvironment and Genetic Alterations in Mesothelioma.

Malignant pleural mesothelioma (MPM) is a rare and fatal disease of the pleural lining. Up to 80% of the MPM cases are linked to asbestos exposure. Even though its use has been banned in the industrialized countries, the cases continue to increase. MPM is a lethal cancer, with very little survival improvements in the last years, mirroring very limited therapeutic advances. Platinum-based chemotherapy in combination with pemetrexed and surgery are the standard of care, but prognosis is still unacceptably poor with median overall survival of approximately 12 months. The genomic landscape of MPM has been widely characterized showing a low mutational burden and the impairment of tumor suppressor genes. Among them, BAP1 and BLM are present as a germline inactivation in a small subset of patients and increases predisposition to tumorigenesis. Other studies have demonstrated a high frequency of mutations in DNA repair genes. Many therapy approaches targeting these alterations have emerged and are under evaluation in the clinic. High-throughput technologies have allowed the detection of more complex molecular events, like chromotripsis and revealed different transcriptional programs for each histological subtype. Transcriptional analysis has also paved the way to the study of tumor-infiltrating cells, thus shedding lights on the crosstalk between tumor cells and the microenvironment. The tumor microenvironment of MPM is indeed crucial for the pathogenesis and outcome of this disease; it is characterized by an inflammatory response to asbestos exposure, involving a variety of chemokines and suppressive immune cells such as M2-like macrophages and regulatory T cells. Another important feature of MPM is the dysregulation of microRNA expression, being frequently linked to cancer development and drug resistance. This review will give a detailed overview of all the above mentioned features of MPM in order to improve the understanding of this disease and the development of new therapeutic strategies.

Immunohistochemical Expression of Serine and Arginine-Rich Splicing Factor 1 (SRSF1) in Fluoro-Edenite-Induced Malignant Mesothelioma: A Preliminary Study.

The Serine and Arginine-Rich Splicing Factor 1 (SRSF1) has a proto-oncogenic function, being associated with angiogenesis and frequently overexpressed in many human malignant neoplasms. Its immunohistochemical expression has never been investigated in malignant pleural mesothelioma (MPM). We evaluated SRSF1 immunoexpression and its possible relation to angiogenesis in a selected cohort of 10 fluoro-edenite(FE)-induced MPM cases. Methods: Immunohistochemical analyses with an anti-SRSF1 antibody were performed. We interpreted the cases as positive if tumor cell nuclei were stained; a semi-quantitative analysis of the cases was performed by evaluating the intensity of staining and the percentage of tumor positive cells. A microvessel density (MVD) count was also performed. Results: High and low immunoexpressions of SRSF1 were seen in six and four MPMs, respectively. A trend of shorter overall survival was found in FE-induced MPM patients with SRSF1 overexpression. In addition, a significant association between high-MVD and high SRSF1 immunoexpression (p = 0.0476) was found. Conclusions: SRSF1 appears to be involved in MPM pathogenesis and its immunoexpression may represent a prognostic biomarker capable of identifying subgroups of patients with different prognosis. However, given the preliminary nature of the present study, further investigations on larger series, and additional in vitro studies, are required to validate our findings.

New DNA Methylation Signals for Malignant Pleural Mesothelioma Risk Assessment.

Simple SummaryOur study investigated DNA methylation differences in easily accessible white blood cells (WBCs) between malignant pleural mesothelioma (MPM) cases and asbestos-exposed cancer-free controls. A multiple regression model highlighted that the methylation level of two single CpGs (cg03546163 in FKBP5 and cg06633438 in MLLT1) are independent MPM markers. The epigenetic changes at the FKBP5 and MLLT1 genes were robustly associated with MPM in asbestos-exposed subjects. Interaction analyses showed that MPM cases and cancer-free controls showed DNAm differences which may be linked to asbestos exposure.Malignant pleural mesothelioma (MPM) is a rare and aggressive neoplasm. Patients are usually diagnosed when current treatments have limited benefits, highlighting the need for noninvasive tests aimed at an MPM risk assessment tool that might improve life expectancy. Three hundred asbestos-exposed subjects (163 MPM cases and 137 cancer-free controls), from the same geographical region in Italy, were recruited. The evaluation of asbestos exposure was conducted considering the frequency, the duration and the intensity of occupational, environmental and domestic exposure. A genome-wide methylation array was performed to identify novel blood DNA methylation (DNAm) markers of MPM. Multiple regression analyses adjusting for potential confounding factors and interaction between asbestos exposure and DNAm on the MPM odds ratio were applied. Epigenome-wide analysis (EWAS) revealed 12 single-CpGs associated with the disease. Two of these showed high statistical power (99%) and effect size (>0.05) after false discovery rate (FDR) multiple comparison corrections: (i) cg03546163 in FKBP5, significantly hypomethylated in cases (Mean Difference in beta values (MD) = −0.09, 95% CI = −0.12|−0.06, p = 1.2 × 10−7), and (ii) cg06633438 in MLLT1, statistically hypermethylated in cases (MD = 0.07, 95% CI = 0.04|0.10, p = 1.0 × 10−6). Based on the interaction analysis, asbestos exposure and epigenetic profile together may improve MPM risk assessment. Above-median asbestos exposure and hypomethylation of cg03546163 in FKBP5 (OR = 20.84, 95% CI = 8.71|53.96, p = 5.5 × 10−11) and hypermethylation of cg06633438 in MLLT1 (OR = 11.71, 95% CI = 4.97|29.64, p = 5.9 × 10−8) genes compared to below-median asbestos exposure and hyper/hypomethylation of single-CpG DNAm, respectively. Receiver Operation Characteristics (ROC) for Case-Control Discrimination showed a significant increase in MPM discrimination when DNAm information was added in the model (baseline model, BM: asbestos exposure, age, gender and white blood cells); area under the curve, AUC = 0.75; BM + cg03546163 at FKBP5. AUC = 0.89, 2.1 × 10−7; BM + cg06633438 at MLLT1. AUC = 0.89, 6.3 × 10−8. Validation and replication procedures, considering independent sample size and a different DNAm analysis technique, confirmed the observed associations. Our results suggest the potential application of DNAm profiles in blood to develop noninvasive tests for MPM risk assessment in asbestos-exposed subjects.

Malignant Pleural Mesothelioma Epidemiology in the United States From 2000 to 2016.

IntroductionPleural mesothelioma constitutes about 80% of all mesotheliomas. The peak incidence of malignant mesothelioma estimated using the cancer registries was in early 1990 to 2000 in the United States. The disease is primarily associated with asbestos exposure. The latency period between asbestos exposure and the development of malignant pleural mesothelioma (MPM) can range anywhere from 15 to 60 years. Asbestos exposure was peaked during the industrial revolution and World War II due to military and shipyard exposures. It is often difficult for the pathologist to distinguish different histological subtypes; due to the disease's rarity and the inadequate tissue sample obtained. There is no available data on the difference in epidemiology of different subtypes of MPM. Surveillance Epidemiology and End Results (SEER), cancer incidence data include population-based registries covering approximately 34.6% of the U.S. population. Here in our study, we analyze malignant pleural mesothelioma epidemiology in the United States, emphasizing different histological subtypes.MethodsSEER data from 2000 to 2016 was used in our study. The primary site of cancer is selected as pleura, and malignant behavior only is selected as the filter. Data were analyzed using the SEER stat program. Overall epidemiology of MPM and epidemiology of epithelioid, fibrous, and biphasic histological subtypes were analyzed separately. We used annual percentage change (APC) to evaluate the trend in the epidemiology of MPM.Results summaryA total of 11,857 cases of MPM were included in the primary cohort from the SEER 18 registry from 2000 to 2016. The total prevalence of MPM was highest in 2009 and was lowest in 2016. The APC in MPM incidence during this period is -2.0. After removing 5,989 cases with non-specified histology during the same period, the APC for each histological type is -0.7 for fibrous type, 1.8 for epithelioid type, and 2.9 for biphasic type. Out of 17 regional registries included in the study, the greatest statistically significant change in APC was seen in the Hawaiian registry -4.1. In contrast, the lowest statistically significant difference was seen in Seattle (Puget Sound) registry -1.7. The APC in the incidence of MPM among males during the study period was -2.4 while that of females was -0.9. The Iowa registry showed a statistically significant increase in APC of the epithelioid malignant mesothelioma with a statistically insignificant reduction in the overall MPM APC.ConclusionThe overall incidence of MPM in the United States is declining, while the data showed an increase in the incidence of epithelioid and biphasic histological subtypes. The authors believe that these conflicting results can be attributed to improved histological diagnosis and improved biopsy techniques.

Identification of distinct immune landscapes using an automated nine-color multiplex immunofluorescence staining panel and image analysis in paraffin tumor tissues

Immune profiling is becoming a vital tool for identifying predictive and prognostic markers for translational studies. The study of the tumor microenvironment (TME) in paraffin tumor tissues such as malignant pleural mesothelioma (MPM) could yield insights to actionable targets to improve patient outcome. Here, we optimized and tested a new immune-profiling method to characterize immune cell phenotypes in paraffin tissues and explore the co-localization and spatial distribution between the immune cells within the TME and the stromal or tumor compartments. Tonsil tissues and tissue microarray (TMA) were used to optimize an automated nine-color multiplex immunofluorescence (mIF) panel to study the TME using eight antibodies: PD-L1, PD-1, CD3, CD8, Foxp3, CD68, KI67, and pancytokeratin. To explore the potential role of the cells into the TME with this mIF panel we applied this panel in twelve MPM cases to assess the multiple cell phenotypes obtained from the image analysis and well as their spatial distribution in this cohort. We successful optimized and applied an automated nine-color mIF panel to explore a small set of MPM cases. Image analysis showed a high degree of cell phenotype diversity with immunosuppression patterns in the TME of the MPM cases. Mapping the geographic cell phenotype distribution in the TME, we were able to identify two distinct, complex immune landscapes characterized by specific patterns of cellular distribution as well as cell phenotype interactions with malignant cells. Successful we showed the optimization and reproducibility of our mIF panel and their incorporation for comprehensive TME immune profiling into translational studies that could refine our ability to correlate immunologic phenotypes with specific patterns of cells distribution and distance analysis. Overall, this will improve our ability to understand the behavior of cells within the TME and predict new treatment strategies to improve patient outcome.

Expression and clinical significance of SETD2 in maligant pleural mesothelioma

Objective: To analyze the gene mutation profile in malignant pleural mesothelioma (MPM) and investigate the expression of high-frequency mutant genes and its relationship with clinicopathological parameters. To screen out key genes and clinicopathologic factors related to the prognosis of MPM patients. Methods: The second generation sequencing data, somatic mutation data and clinical pathological data of 86 MPM cases and gene chip expression data of 89 MPM cases were downloaded from the Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) in March 2020. Summarize the gene mutation profile of tissue samples in the TCGA database and analyze the relationship between the expression level of high-frequency mutation genes and the clinicopathological characteristics, asbestos exposure history and prognosis of MPM patients. The genes significantly related to MPM prognosis were screened out for gene set enrichment analysis (GSEA) . Survival analysis and GSEA were performed for the selected key genes and clinicopathological features verification using the microarray expression data from the GEO database. Results: The top 10 genes with highest single nucleotide variations frequencies were BAP1, NF2, TP53, TTN, SETD2, LATS2, CCDC168, FAT4, PTCH1 and ZNF469. The high expression rates of NF2, TP53, SETD2 and CCDC168 genes in wild type were higher than those of mutated type, and the differences were statistically significant (P<0.05) . Cox multivariate analysis of TCGA data showed that MPM patients with epithelial type (HR=0.425, 95%CI: 0.235-0.767, P<0.01) and SETD2 low expression (HR=0.516, 95%CI: 0.307-0.868, P=0.011) had lower risk of death. The survival analysis of GEO data verified that patients with epithelial type MPM had longer survival time, while patients with sarcoma type MPM had shortest survival time (P<0.01) . GSEA showed that SETD2 was involved in G2M checkpoint, E2F targets, MYC signaling pathways, protein secretion, mitotic spindle, MTORC1 pathway, TGF-β pathway, androgen response and uv response. Conclusion: MPM is accompanied with higher frequency of gene mutations represented by BAP1, NF2, TP53, TTN, SETD2, LATS2 and so on. SETD2 expression level and epithelia type of MPM may be influential factors for MPM prognosis.

Malignant pleural mesothelioma: Experience of the Medical Oncology Department of Hassan II Hospital in Fez, Morocco

Background: Malignant pleural mesothelioma (MPM) is a primary, rare and aggressive malignant tumor, closely correlated with asbestos exposure. Aim: The objective of this work is to study the main epidemiological, clinical, histological and therapeutic aspects of these tumors and to compare our results with those reported in the literature. Methods: We conducted a retrospective study of 8 cases of MPM collected at the medical oncology department of CHU Hassan II in Fez, for a period of 8 years from January 2011 to January 2019. Results: The mean age at diagnosis was 53 years with an F/H sex ratio of 1.7. Occupational exposure to asbestos was found in only one patient. Pleural effusion syndrome was present in all patients. Biopsy was done under thoracoscopy in 7patients (87.5%). MPM were mostly stage IV (50%). The standard treatment was conventional chemotherapy based on platinum, administered to all patients. After an average number of 4 courses, the objective response rate was 12.5%, and the disease control rate was 50%. Second line chemotherapy consisted of monotherapy with NAVELBINE (67%) or PEMETREXED (33%). After a median follow–up of 17 months, the median of progression–free survival was 5 months, and that of overall survival was 8 months. Conclusion: Based on the results of this study, we conclude that MPM is a very rare tumor in Morocco with poor prognosis. Prognostic factors affecting survival could not be studied due to the low number of patients included in the study, and the lack of data on medical records.

Clinical prognostic factors in pleural mesothelioma: best supportive care and anti-tumor treatments in a real-life setting

Background This study aims to investigate patient- and disease characteristics associated with survival in malignant pleural mesothelioma (MPM) patients with anti-tumor treatment or with best supportive care (BSC). Materials and methods Consecutive MPM cases diagnosed in North Denmark Region from 1972 to 2015 were reevaluated and verified by two pathologists using modern immunohistochemical techniques. Danish registries and hospital records were used to gather patient-, asbestos exposure-, and disease information. Results Of the 279 patients, anti-tumor treatment was administered to 184 patients (66.0%). All of those received chemotherapy alone or as part of a multimodal treatment, where pemetrexed was given to 126 (68.5%) patients. Asbestos exposure was documented in 92.5% of all patients. In the treated group, mean age was lower (66 years versus 74 years, p < 0.01), rate of occupational asbestos exposure was higher (74.5 versus 54.7%, p < 0.01), more patients had better performance score (98.4 versus 60%, p < 0.01) and stage was lower (81 versus 63.2%, p < 0.01) compared to the BSC group. Multivariate analysis showed that epithelioid subtype was the only common prognostic factor for OS in both groups. In BSC patients, good PS and female gender was associated with improved OS. Median overall survival (OS) was 17 versus 4 months (p < 0.01), and independently of the histopathological subtype, the median and 2-year survival was higher in the treated versus the BSC group (p < 0.02). Conclusions This retrospective study showed that epithelioid subtype is the only independent positive prognostic factor of survival in treated patients with MPM. For BSC patients, the epithelioid subtype, good PS, and female gender were positive prognostic factors, while age and comorbidities were not significant. This study with long-term follow-up of treated and BSC MPM patients can contribute to the clinical stratification of patients. Further validation is appropriate to verify these findings.

Fluorescence in situ hybridization detection of chromosome 22 monosomy in pleural effusion cytology for the diagnosis of mesothelioma.

Malignant pleural mesothelioma (MPM) is characterized by mutations in several genes, including cyclin-dependent kinase-inhibitor 2A/p16 in the 9p21 locus, BRCA1-associated protein 1 (BAP1), and neurofibromatosis type 2 (NF2) in the 22q12 locus. Recent studies indicate that fluorescence in situ hybridization (FISH) detects hemizygous loss of NF2 in tissue specimens of MPM. The authors investigated whether NF2 FISH, either alone or in combination with other diagnostic assays (9p21 FISH, methylthioadenosine phosphorylase [MTAP] immunohistochemistry [IHC], and BAP1 IHC), effectively distinguishes MPM cells from reactive mesothelial cells (RMCs) in cell blocks prepared from pleural effusions. FISH assays were used to examine the deletion status of NF2 and 9p21, and IHC was used to determine the expression of MTAP and BAP1 in cell blocks from 54 cases with MPM and 18 cases with RMCs. Hemizygous NF2 loss (chromosome 22 monosomy or hemizygous deletion) showed 51.9% sensitivity (48.1% for chromosome 22 monosomy and 3.7% for hemizygous deletion) and 100% specificity in differentiating MPM cells from RMCs. Combinations of NF2 FISH, 9p21 FISH, and BAP1 IHC assays yielded greater sensitivity (98.1%) than any assay alone (9p21 FISH, 61.1%; MTAP IHC, 52.8%; or BAP1 IHC, 60.4%). The level of hemizygous NF2 loss in cell blocks positively correlated with that in corresponding tissues. Furthermore, to overcome cytologic specimen-specific challenges, FISH combined with cytokeratin AE1/AE3 immunofluorescence was necessary in 25.9% of MPM cases for FISH assessment of predominantly scattered MPM cells. NF2 FISH alone or in combination with other diagnostic assays effectively differentiates MPM cells from RMCs in cell blocks prepared from pleural effusions.

DNA Methylation of FKBP5 as Predictor of Overall Survival in Malignant Pleural Mesothelioma.

Simple SummaryOur study is the first one to investigate DNA methylation changes in white blood cells (WBCs) from easily accessible peripheral blood as malignant pleural mesothelioma (MPM) survival biomarker. The Cox proportional hazards regression model highlighted that the methylation status of the CpG dinucleotide cg03546163 is an independent marker of prognosis in MPM patients with a better performance than traditional inflammation-based scores such as lymphocyte-to-monocyte ratio (LMR). Biological validation and replication showed that epigenetic changes at the FKBP5 gene were robustly associated with overall survival (OS) in MPM cases. The identification of simple and valuable prognostic markers for MPM will enable clinicians to select patients who are most likely to benefit from aggressive therapies and avoid subjecting non-responder patients to ineffective treatment.Malignant pleural mesothelioma (MPM) is an aggressive tumor with median survival of 12 months and limited effective treatments. The scope of this study was to study the relationship between blood DNA methylation (DNAm) and overall survival (OS) aiming at a noninvasive prognostic test. We investigated a cohort of 159 incident asbestos exposed MPM cases enrolled in an Italian area with high incidence of mesothelioma. Considering 12 months as a cut-off for OS, epigenome-wide association study (EWAS) revealed statistically significant (p value = 7.7 × 10−9) OS-related differential methylation of a single-CpG (cg03546163), located in the 5′UTR region of the FKBP5 gene. This is an independent marker of prognosis in MPM patients with a better performance than traditional inflammation-based scores such as lymphocyte-to-monocyte ratio (LMR). Cases with DNAm < 0.45 at the cg03546163 had significantly poor survival compared with those showing DNAm ≥ 0.45 (mean: 243 versus 534 days; p value< 0.001). Epigenetic changes at the FKBP5 gene were robustly associated with OS in MPM cases. Our results showed that blood DNA methylation levels could be promising and dynamic prognostic biomarkers in MPM.

MALIGNANT PLEURAL MESOTHELIOMA WITH NO ASBESTOS EXPOSURE

SESSION TITLE: Medical Student/Resident Lung Cancer Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: Malignant pleural mesothelioma (MPM) is the primary malignant tumor of the pleura which is highly aggressive with median survival around 12 months. This cancer is linked with asbestos exposure, but in 20% cases, the exposure fails to be found. CASE PRESENTATION: A 73 year- old lifetime non-smoking female presented with sharp, non-radiating, lower right chest pain. Her vital signs were normal and the physical exam was significant only for mild tenderness over her right flank. A CT angiogram of chest showed a soft tissue mass within the right posterior pleura measuring up to 3.4cm with enlarged subcarinal lymph nodes measuring up to 15mm. She denied any direct or indirect asbestos exposure, worked as a homemaker and her husband worked in agriculture. Subsequent PET scan was compatible with a malignant process. Bronchoscopy with biopsy of the subcarinal lymph node showed a poorly differentiated epithelioid neoplasm. A confirmatory CT-guided biopsy showed the same. Tumor cells had a high nuclear-cytoplasmic ratio, hyperchromatic nuclei with irregular contours. The cells showed positive immunostaining with Calretinin, WT-1, GATA-3, D2-40. The above workup was consistent with an atypical presentation of mesothelioma, stage IIIA (cT3N1), not felt to be resectable given subcarinal nodal involvement, and the patient underwent radiation followed by systemic chemotherapy. DISCUSSION: MPM affects men in 80% of cases and it is most frequent around the age of 60 years [1]. The male to female ratio is 4:1 with a predominance of right side over the left. The main etiological factor is previous exposure to asbestos with a typical long latency period of around 20 - 40 years. Few cases of MPM without asbestos exposure have been reported in literature [2,3]. The possibility of association of MPM and exposure to some dust or chemicals (stone cutter, leather factory or textile factory worker, agricultural chemicals) has also been reported. Typical presentation includes progressive dyspnea, cough and chest pain . Weight loss and generalized fatigue are seen at advanced stages and linked with poor outcomes. The most common radiological presentation is a unilateral pleural effusion, which is recurrent, and sometimes exudative and hemorrhagic. Bronchoscopy has a high sensitivity of 95% for diagnosis of MPM. In our case the patient is a lifetime non-smoker without any direct or indirect asbestos exposure. CONCLUSIONS: MPM has a poor prognosis despite advancement in surgery and oncology. Although linked with asbestos exposure, in 20% of the cases this exposure fails to be found. A significant increase in survival among MPM patients can be reached through earlier diagnosis. This case was unusual in that the initial presentation was due to pain, there was no significant pleural effusion identified, and no known exposure to asbestos. Reference #1: Robinson BW, Musk AW, Lake RA. Malignant mesothelioma. Lancet. 2005; 366:397-408. Reference #2: Batahar SA, Ouradi O, Elidrissi S, Amro L. Pleural Mesothelioma with No Asbestos Exposure: A Case Report. Journal of Clinical and Diagnostic Research : JCDR. 2016 Nov;10(11):OD07-OD08. DOI: 10.7860/JCDR/2016/21066.8849. Reference #3: Kant S, Verma SK, Sanjay. Malignant pleural mesothelioma without asbestos exposure with distant metastasis in a peripheral lymph node: a case report. Lung India. 2008;25(1):31–33. doi:10.4103/0970-2113.44137 DISCLOSURES: No relevant relationships by SYED ABBAS, source=Web Response No relevant relationships by Amarpreet Bhalla, source=Web Response No relevant relationships by Aditi Desai, source=Web Response No relevant relationships by Vivek Murthy, source=Web Response

Does size matter? -a population-based analysis of malignant pleural mesothelioma.

BackgroundThe 8th edition staging system for malignant pleural mesothelioma (MPM) has been proposed. The size of tumor is not taken into consideration. We intend to elucidate the prognostic value of the size of MPM and evaluate the current staging system via the data of SEER database.MethodsAll cases of primary MPM were identified and extracted from the SEER database during the period of 2004–2016. The endpoints were overall survival (OS) and cancer-specific survival (CSS) which were analyzed using Kaplan-Meier method. Log-rank test and Cox regression were utilized to identify the prognostic factors.ResultsA total of 2,138 patients were included in the primary cohort. The 1-, 3- and 5-year survival rates of MPM were 39.4%, 11.8% and 3.8%. Older, male and advanced stage patients accounted for larger proportion of the cohort. Besides tumor extension, lymph node involvement and metastatic status, tumor size, pathological type and differentiation grade were significant prognostic factors. In the stratified analysis of tumor extension, size is a significant prognostic factor in T2 patients and indicates inferior survival outcomes. Surgery, chemotherapy and radiation can increase both OS and CSS in MPM patients. Triple combination treatments showed a superiority to other treatments.ConclusionsTumor size matters in the prognosis of MPM especially in the early stage of MPM patients. The adjusted TNM staging system incorporating tumor size has better accuracy than the 8th edition IMIG system. However, some stages had not been fully identified. More cases of early stages are warranted for essential revision.

Abstract B14: Discovery of YAP-TEAD protein-protein interaction inhibitors (PPI) for treating malignant pleural mesothelioma (MPM)

Abstract We have recently reported the development of YAP-TEAD interaction inhibitors that disrupt the YAP-TEAD complex and block proliferation of tumor cells. These compounds represent promising new treatment modalities for mesothelioma where the Hippo pathway is highly deregulated, with around 45% of MPM cases displaying a mutation of NF2 or LATS and predominantly nuclear YAP localization. MPM is an extremely aggressive disease with limited treatment options and no cure and is inherently chemoresistant, with only 50% of patients responding to the standard-of-care treatment; consequently, it has a very poor prognosis. The aim of this study was to support a multipronged approach to treat MPM. We have first established the in vitro proof of concept using siRNA experiments. Then, we have evaluated the effect of several Inventiva compounds (YAP-TEAD inhibitors) on the proliferation of a well-characterized YAP-dependent mesothelioma cell line (H2052) and on a large panel of MPM cells. We have further demonstrated the mechanism of action (MOA) of our compounds investigating the nuclear localization of YAP, the YAP-TEAD interactions, and the YAP protein expression levels in H2052 cancer cell line. To demonstrate the MOA, we have used immunofluorescence, proximity ligation assay, as well as Co-IP and Western blot experiments. Furthermore, we have examined the effect of IVA compounds in combination with the standard-of-care agent pemetrexed in a 3D spheroid model, and demonstrated the target engagement by looking at YAP-TEAD target gene expression. The effect of IVA compounds has been compared to this obtained with siRNA transfection. To assess the efficacy of pemetrexed +/- Inventiva compounds, we exposed H2052 cells to either each of the single agents or to their combination for 4 or 15 days in 2D or in 3D cultures. We used EdU incorporation assay or the measure of the spheroid area to access cell proliferation. We found a synergistic effect between YAP-TEAD inhibitors and pemetrexed, leading to a drastic inhibition of cancer cell proliferation and an increase of cytotoxicity. This suggests that YAP-TEAD inhibitors used in combination with existing chemotherapeutics could be used to attenuate multidrug resistance and resensitize chemoresistant cancer cells. We are currently exploring the effect of Inventiva compounds in H2052 mouse xenograft model. This study will be expanded to other indications and combination strategies where standard-of-care agents are ineffective and YAP is activated. Citation Format: Anne Soudé, Martine Barth, Jean-Michel Luccarini, Séverine Delaporte, Florence Chirade, Christelle Valaire, Aude Boulay, Geneviève Cheret, Marie Dorchie, Céline Estivalet, Pascale Tuya-Boustugue, Robin Tranchand, Didier Jean, Lisa Quetel, Jean-Baptiste Assié, Irena Konstantinova, Jean-Louis Junien, Pierre Broqua. Discovery of YAP-TEAD protein-protein interaction inhibitors (PPI) for treating malignant pleural mesothelioma (MPM) [abstract]. In: Proceedings of the AACR Special Conference on the Hippo Pathway: Signaling, Cancer, and Beyond; 2019 May 8-11; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2020;18(8_Suppl):Abstract nr B14.

Telomerase Reverse Transcriptase Promoter Mutations Identify a Genomically Defined and Highly Aggressive Human Pleural Mesothelioma Subgroup.

Human malignant pleural mesothelioma (MPM) is characterized by dismal prognosis. Consequently, dissection of molecular mechanisms driving malignancy is of key importance. Here we investigate whether activating mutations in the telomerase reverse transcriptase (TERT) gene promoter are present in MPM and associated with disease progression, cell immortalization, and genomic alteration patterns. TERT promoters were sequenced in 182 MPM samples and compared with clinicopathologic characteristics. Surgical specimens from 45 patients with MPM were tested for in vitro immortalization. The respective MPM cell models (N = 22) were analyzed by array comparative genomic hybridization, gene expression profiling, exome sequencing as well as TRAP, telomere length, and luciferase promoter assays. TERT promoter mutations were detected in 19 of 182 (10.4%) MPM cases and significantly associated with advanced disease and nonepithelioid histology. Mutations independently predicted shorter overall survival in both histologic MPM subtypes. Moreover, 9 of 9 (100%) mutated but only 13 of 36 (36.1%) wild-type samples formed immortalized cell lines. TERT promoter mutations were associated with enforced promoter activity and TERT mRNA expression, while neither telomerase activity nor telomere lengths were significantly altered. TERT promoter-mutated MPM cases exhibited distinctly reduced chromosomal alterations and specific mutation patterns. While BAP1 mutations/deletions were exclusive with TERT promoter mutations, homozygous deletions at the RBFOX1 and the GSTT1 loci were clearly enriched in mutated cases. TERT promoter mutations independently predict a dismal course of disease in human MPM. The altered genomic aberration pattern indicates that TERT promoter mutations identify a novel, highly aggressive MPM subtype presumably based on a specific malignant transformation process.

Adenosine Deaminase in Pleural Effusion and Its Relationship with Clinical Parameters in Patients with Malignant Pleural Mesothelioma

Pleural effusion adenosine deaminase (ADA) levels are elevated in various diseases. We investigated whether pleural effusion ADA levels differ among patients with malignant pleural mesothelioma (MPM), lung cancer (LC), and benign diseases, including tuberculous pleurisy. We examined 329 patients from February 2002 to July 2013. There were 131 MPM cases with ADA levels of 32.29 IU/L; 117 LC cases with ADA levels of 21.12 IU/L; 54 benign disease cases with ADA levels of 20.98 IU/L. A significant difference existed in pleural effusion ADA levels between MPM and benign disease patients. Pleural effusion ADA levels were significantly higher in MPM patients.

Genomic-based ancillary assays offer improved diagnostic yield of effusion cytology with potential challenges in malignant pleural mesothelioma.

BRCA1-associated protein 1 (BAP1) or methylthioadenosine phosphorylase (MTAP) immunohistochemistry (IHC) or 9p21 fluorescence in situ hybridization (FISH) are useful for the diagnosis of malignant pleural mesothelioma (MPM). However, the effect of these assays on the diagnostic yield of effusion cytology in MPM cases with suspicious cytomorphology or the diagnostic challenges in BAP1 or MTAP IHC have not been fully elucidated. Two cohorts of cytologic preparations obtained from pleural effusions were examined: MPM cases in cohort 1 were used to evaluate whether BAP1 or MTAP IHC or 9p21 FISH increase the diagnostic yield of effusion cytology; cohort 2 included cases suspicious for MPM, to which BAP1 or MTAP IHC was applied to clarify the challenges in the clinical assessment of these assays. In cohort 1 (n = 28), either assay elevated 62.5% of class II or III cases to class V. In cohort 2 (n = 139), 21.7% of BAP1 immunocytochemistry in smears and 10.6% of BAP1 IHC and 9.4% of MTAP IHC in cell blocks, were identified to be challenging. The application of genomic-based assays increased the diagnostic yield of effusion cytology in the diagnosis of MPM. However, diagnostic challenges limit the application of these assays in some cases.

Histopathological and Immunohistochemical Study of D2-40 Expression in Malignant Pleural Mesothelioma and Metastatic Adenocarcinoma

Abstract Background: Malignant pleural mesothelioma (MPM) is known to be an aggressive malignant tumor due to the difficulty of making early diagnosis and its rapid progression. Its incidence is increasing worldwide but no treatment plans are accepted. D2-40 is an immunohistochemical marker (mono-clonal antibody) that has been used as a lymphatic endothelial marker and used in the differential diagnosis of MPM (epi-thelioid type) versus metastatic adenocarcinoma. Fifty spec-imens of the pleural biopsy were viewed. They were diagnosed as 40 cases of MPM (epithelioid type) and 10 cases of meta-static adenocarcinoma (unknown primary origin). These diagnoses based on Hematoxylin and Eosin (Hx & E) stained sections and other immunohistochemical markers such as calretinin, carcinoembryonic antigen (CEA), thyroid transcrip-tion factor-1 (TTF-1). Aim of Study: To compare D2-40 immunostaining in MPM (epithelioid type) and metastatic adenocarcinoma with deter-mining its sensitivity and specificity in both types. Results: All cases of MPM epithelioid type were positive for D2-40 while all cases of metastatic adenocarcinoma were negative (both sensitivity and specificity= 100%). D2-40 staining result was considered positive or negative according to the presence or absence of membranous staining. Statistical analysis was done for assessment of D2-40 expression in both types of tumors by using SPSS version 21. Conclusion: Routine immunohistochemical work using D2-40 with calretinin is recommended. D2-40 would be superior to calretinin because of its membranous pattern of staining which does not obscure the cytological features of the tumor cells as compared to calretinin.