Malignant Pleural Mesothelioma: A Population-Based Study of Survival

Epidemiology of mesothelioma in the 21st century in Europe and the United States, 40 years after restricted/banned asbestos use

Research has established a strong association between asbestos exposure and malignant mesothelioma, a deadly form of cancer. Since the early 1980’s many countries have restricted or banned the production of asbestos, leading to a decline of occupational asbestos exposure in many industrialized countries. However, some countries continue to use asbestos, and worldwide rates of mesothelioma are still increasing. Because of the long latency between exposure and mesothelioma occurrence and the persistence of environmental exposure, incidence rates (IR) may decrease very slowly for several years ahead. In this review, we examine estimates of asbestos consumption before widespread asbestos regulations and the trends in incidence and mortality rates, as well as changes over time for the United States and Europe. In some countries with earlier asbestos restrictions, mesothelioma incidence has been in a modest decline over time. However, asbestos exposure is still a burden worldwide and legislative action is needed to obtain a full ban. The pattern of mesothelioma is shifting from a mostly male disease to a disease that affects females as well in substantial numbers. Studies on unknown sources of asbestos exposure, of other sources of natural exposure to asbestos and asbestos-like fibers, as well as of individual genetic susceptibility to asbestos fibers are needed.

An Emerging Model for Cancer Development from a Tumor Microenvironment Perspective in Mice and Humans

In the past, cancer development was studied in terms of genetic mutations acquired in cancer cells at each stage of the development. We present an emerging model for cancer development in which the tumor microenvironment (TME) plays an integral part. In this model, the tumor development is initiated by a slowly growing nearly homogeneous colony of cancer cells that can evade detection by the cell's innate mechanism of immunity such as natural killer (NK) cells (first stage; colonization). Subsequently, the colony develops into a tumor filled with lymphocytes and stromal cells, releasing pro-inflammatory cytokines, growth factors, and chemokines (second stage; lymphocyte infiltration). Cancer progression proceeds to a well-vesiculated silent tumor releasing no inflammatory signal, being nearly devoid of lymphocytes (third stage; silenced). Eventually some cancer cells within a tumor undertake epithelial-to-mesenchymal transition (EMT), which leads to cancer metastasis (fourth stage; EMT). If a circulating metastasized cancer cell finds a niche in a new tissue and evades detection by NK cells, it can establish a new colony in which very few stromal cells are present (fifth stage; metastasis), which is much like a colony at the first stage of development. At every stage, cancer cells influence their own TME, and in turn, the TME influences the cancer cells contained within, either by direct interaction between cancer cells and stromal cells or through exchange of cytokines. In this article, we examine clinical findings and animal experiments pertaining to this paradigm-shifting model and consider if, indeed, some aspects of cancer development are governed solely by the TME.

Inhibition of cyclin-dependent kinase 7 down-regulates yes-associated protein expression in mesothelioma cells

Cyclin-dependent kinase 7 (CDK7) is a protein kinase that plays a major role in transcription initiation. Yes-associated protein (YAP) is a main effector of the Hippo/YAP signalling pathway. Here, we investigated the role of CDK7 on YAP regulation in human malignant pleural mesothelioma (MPM). We found that in microarray samples of human MPM tissue, immunohistochemistry staining showed correlation between the expression level of CDK7 and YAP (n = 70, r = .513). In MPM cells, CDK7 expression level was significantly correlated with GTIIC reporter activity (r = .886, P = .019). Inhibition of CDK7 by siRNA decreased the YAP protein level and the GTIIC reporter activity in the MPM cell lines 211H, H290 and H2052. Degradation of the YAP protein was accelerated after CDK7 knockdown in 211H, H290 and H2052 cells. Inhibition of CDK7 reduced tumour cell migration and invasion, as well as tumorsphere formation ability. Restoration of the CDK7 gene rescued the YAP protein level and GTIIC reporter activity after siRNA knockdown in 211H and H2052 cells. Finally, we performed a co-immunoprecipitation analysis using an anti-YAP antibody and captured the CDK7 protein in 211H cells. Our results suggest that CDK7 inhibition reduces the YAP protein level by promoting its degradation and suppresses the migration and invasion of MPM cells. Cyclin-dependent kinase 7 may be a promising therapeutic target for MPM.

Diagnostic value of biopsy sampling in predicting histology in patients with diffuse malignant pleural mesothelioma

BACKGROUND

The classification of diffuse malignant mesothelioma into epithelioid, biphasic, and sarcomatoid types is based on histologic patterns. The diagnosis is made on biopsies, and because of intratumoral heterogeneity, they may not be representative of the entire tumor. The number and volume of biopsies needed to reach diagnostic accuracy in diffuse malignant mesothelioma and their prognostic value remain unclear.

METHODS

This study examined 759 consecutive patients with pleural diffuse malignant mesothelioma treated by pleurectomy/decortication or extrapleural pneumonectomy for the presence of epithelioid and/or sarcomatoid histology and classified both the presurgery biopsies (core-needle or thoracoscopic) and surgical resection specimens. The number and volume of biopsies were correlated with pre- and postsurgery histologies and overall survival.

RESULTS

Diffuse malignant mesothelioma was classified as epithelioid (76%), biphasic (18%), sarcomatoid (5%), or indeterminate (1%) in biopsies and as epithelioid (64%), biphasic (32%), and sarcomatoid (4%) in surgical resection specimens (overall concordance, 80.6%). The positive likelihood ratios were 2.4, 13.6, and 90.1 for biopsies with epithelioid, biphasic, and sarcomatoid histologies, respectively. Concordant histologies between biopsies and resections were associated with a higher number of biopsies (median tissue blocks for concordant histologies vs discordant histologies, 3 vs 2; P < .002) but were less associated with a higher volume (median, 1.2 vs 1.1 cm3 ; P = .06). In a multivariate analysis, overall survival was independently predicted by histology in the resection specimen (P < .0001) but not in the biopsy (P = .09).

CONCLUSIONS

In contrast to epithelioid histology, sarcomatoid histology in biopsies is highly accurate. Despite intratumoral heterogeneity, the accuracy of histologic classification increases with the number of tissue blocks examined, emphasizing the diagnostic value of extensive sampling by presurgery biopsies.

Actualités et perspectives concernant l’immunothérapie en oncologie thoracique

IMMUNOTHERAPY IN THORACIC ONCOLOGY

STATE OF THE ART AND PERSPECTIVES: Immune checkpoint inhibitors (ICI) are monoclonal antibodies that inhibit molecular interaction between an immune checkpoint and its ligand, which leads to increased anti-tumoral immune response, Programmed Death 1 (PD-1) and Cytotoxic T-Lymphocyte Associated-4 (CTLA-4) are the most commonly known immune checkpoints. ICIs are currently placed early in the course of the treatment of patients with non-small cell lung cancer (NSCLC). In France, approvals have been pronounced for nivolumab and pembrolizumab (anti-PD-1 antibodies) as second-line treatments after chemotherapy in patients with advanced NSCLC, and pembrolizumab has been approved as a first-line treatment in patients with advanced NSCLC, without EGFR mutation or ALK rearrangement, with strong (≥50%) PD-L1 (Programmed Death Ligand 1) expression. Atezolizumab is currently soon to be approved as a second-line treatment. Numerous studies are currently evaluating ICIs in thoracic oncology. In this article, we will develop perspectives regarding ICIs for early stage or locally advanced NSCLCs, ICIs used in other thoracic cancers (small cell lung cancer, malignant pleural mesothelioma, thymic epithelial tumors), and trials with combinations involving ICIs: two ICIs combined, or ICIs combined with chemotherapy, radiotherapy or other anti-cancer treatments.

Malignant pleural mesothelioma in Finland: regional and gender variation

BACKGROUND

Malignant pleural mesothelioma (MPM) is a rare occupational cancer with a poor prognosis. Even with a multimodality treatment approach, the treatment outcomes remain unsatisfactory. The use of asbestos has been banned in most developed countries, but MPM continues to be a significant occupational disease also in these countries. Aim of this study is to identify modern epidemiology and assess equality in care.

METHODS

Our study cohort consists of 1010 patients diagnosed with MPM in Finland during 2000-2012. The data were collected from the Finnish Cancer Registry, the National Workers' Compensation Center Registry and the National Registry of Causes of Death, Statistics Finland.

RESULTS

Women were diagnosed a mean of 4.5 years later than males (p = .001), but survival did not differ (overall median survival 9.7 months). A workers' compensation claim was more common in males (OR 11.0 [95% CI 7.5-16.2]) and in regions with a major asbestos industry (OR 1.7 [95% CI 1.3-2.2]). One-year and three-year survivals did not differ regionally. Patients without chemotherapy treatment had an inferior survival (RR 1.8 [95% CI 1.5-2.0]). The initial survival benefit gained with pemetrexed was diluted at 51 months.

CONCLUSIONS

MPM is a disease with a poor prognosis, although chemotherapy appears to improve survival time. Significant gender and regional variation exists among patients, with notable differences in diagnostic and treatment practices. Long-term outcomes with pemetrexed remain indeterminate.

IMPACT

Emphasize centralized consult services for the diagnosis, treatment and support that patients receive for MPM, facilitating equal outcomes and compensation.

A Novel Prospective Study Assessing the Combination of Photodynamic Therapy and Proton Radiation Therapy: Safety and Outcomes When Treating Malignant Pleural Mesothelioma

Malignant pleural mesothelioma remains difficult to treat, with high failure rates despite optimal therapy. We present a novel prospective trial combining proton therapy (PT) and photodynamic therapy (PDT) and the largest-ever mesothelioma PT experience (n = 10). PDT photosensitizers included porfimer sodium (2 mg·kg-1 ; 24 h drug-light interval) or 2-[1-hexyloxyethyl]-2-devinyl pyropheophorbide-a (HPPH) (4 mg·m-2 ;48 h) with wavelengths of 630 nm to 60J·cm-2 and 665 nm to 15-45J·cm-2 , respectively. With a median age of 69 years, patients were predominantly male (90%) with epithelioid histology (100%) and stage III-IV disease (100%). PT was delivered to a median of 55.0 CGE/1.8-2.0 CGE (range 50-75 CGE) adjuvantly (n = 8) or as salvage therapy (n = 2) following extended pleurectomy/decortication (ePD)/PDT. Two-year local control was 90%, with distant and regional failure rates of 50% and 30%, respectively. All patients received chemotherapy, and four received immunotherapy. Surgical complications included atrial fibrillation (n = 3), pneumonia (n = 2), and deep vein thrombosis (n = 2). Median survival from PT completion was 19.5 months (30.3 months from diagnosis), and 1- and 2-year survival rates were 58% and 29%. No patient experienced CTCAEv4 grade ≥2 acute or late toxicity. Our prolonged survival in very advanced-stage patients compares favorably to survival for PT without PDT and photon therapy with PDT, suggesting possible spatial or systemic cooperativity and immune effect.

miR-182 and miR-183 Promote Cell Proliferation and Invasion by Targeting FOXO1 in Mesothelioma

Dysregulation of miR-182 and miR-183 has been implicated in the progression of several human cancers. Our previous study showed that miR-182 and miR-183 are upregulated in malignant mesothelioma. However, their biological functions remain unclear. We performed in-situ hybridization to analyze the expression of miR-182 and miR-183 in human tissues. Functional analysis was performed by treatment of two mesothelioma cell lines (ACC-MESO1 and CRL-5915) with miR-182 and miR-183 inhibitors. RT-PCR and western blot analysis were conducted to analyze the expression of FOXO1, a known target of both miR-182 and miR-183. Mesothelioma cells treated with FOXO1 siRNA and miR-182/183 inhibitors were also analyzed by evaluating cell proliferation and invasion, as well as expression of FOXO1 and its downstream targets. We confirmed miR-182 expression in 25/29 cases and miR-183 expression in 29/29 cases of human mesothelioma tissue by in-situ hybridization. Notably, inhibition of miR-182 or miR-183 reduced cell proliferation, invasion, migration, and adhesion abilities of mesothelioma cells. Surprisingly, transfection with both miR-182 and miR-183 inhibitors showed even more effects on cell progression. Furthermore, FOXO1 was identified as a target of miR-182 and miR-183 in mesothelioma cells. Inhibition of miR-182 and miR-183 reduced cell proliferation ability via upregulation of FOXO1 and its downstream targets, namely, p27. Moreover, inhibition of miR-182 and miR-183 reduced the cell invasion properties of mesothelioma cells. Our findings indicated that miR-182 and miR-183 promote mesothelioma cell progression via downregulation of FOXO1 and p27. Targeting the miR-182/183—FOXO1 axis could serve as a novel treatment against malignant mesothelioma.

Curcumin induces apoptosis and inhibits angiogenesis in murine malignant mesothelioma

Malignant pleural mesothelioma (MPM) is a rare form of cancer that is associated with asbestos exposure. Unfortunately, current therapies have limited efficacy. Previous studies have indicated that curcumin exerts antiproliferative and antitumor effects, and has low toxicity. The present study aimed to evaluate the anticancer effects of curcumin on the RN5 MPM cell line. The inhibitory effects of curcumin on cell viability were determined using the sulforhodamine B assay. In addition, cell cycle progression was analyzed by propidium iodide (PI) staining and flow cytometry, and curcumin‑induced apoptosis was measured by Annexin V/PI double staining. The translocation of apoptosis-inducing factor (AIF) was assessed by western blotting and immunofluorescence, and the expression levels of the phosphoinositide 3-kinase (PI3K)-AKT serine/threonine kinase (Akt)‑mammalian target of rapamycin (mTOR) signaling pathway proteins and mitochondria-associated proteins were evaluated by western blotting. In vivo antitumor effects were evaluated in a subcutaneous murine model. Briefly, tumors were harvested from the mice, and immunohistochemistry was conducted to evaluate cell proliferation, apoptosis and angiogenesis. The results indicated that curcumin inhibited RN5 cell viability and induced apoptotic cell death. In addition the findings suggested that curcumin-induced cell apoptosis occurred via the mitochondrial pathway, and caspase‑independent and AIF-dependent pathways. Further analysis revealed that curcumin may act as a PI3K-Akt-mTOR signaling pathway inhibitor by downregulating PI3K, p-Akt, p-mTOR and p-p70 ribosomal protein S6 kinase. Furthermore, curcumin inhibited tumor angiogenesis in vivo. In conclusion, curcumin may be potent enough to be developed as a novel therapeutic agent for the treatment of MPM.

Zoledronic acid in the management of mesothelioma - a feasibility study (Zol-A Trial): study protocol for a randomised controlled trial

BACKGROUND

Nitrogen containing bisphosphonates such as zoledronic acid (ZA) are known to contain certain anti-cancer properties. These have been investigated in the past in various cancers such as breast, prostate and colon. ZA in particular has shown promising results in pre-clinical studies. We propose a multicentre double-blind randomised controlled feasibility study to assess the recruitment and acceptability of ZA/placebo alongside chemotherapy in malignant pleural mesothelioma (MPM).

METHODS

Patients will be recruited for a 13-month period from October 2016 to November 2017. Eligible patients will be identified via the regional mesothelioma multidisciplinary team meeting. Those who receive chemotherapy will be randomised to receive either ZA or placebo alongside their chemotherapy. Those who decline chemotherapy will be offered to join the trial on the non-randomised open-labelled arm of the trial. Patients will receive a maximum of six cycles of ZA/placebo, at three-weekly cycles. All patients will be followed up for six months from randomisation. Semi-structured interviews to gather data on acceptability of trial procedures, tolerability of ZA and other relevant information will take place after the participants have completed their six cycles of treatment. For a better understanding about non-participation in mesothelioma trials we also aim to interview those who decline to take part in the trial.

DISCUSSION

The qualitative and quantitative data gathered in this feasibility trial will hopefully pave the way to designing a robust full phase III trial to investigate the potential synergistic effect of ZA and current standard treatment for MPM, cisplatin-pemetrexed combination chemotherapy.

TRIAL REGISTRATION

ISRCTN Registry, ISRCTN45536692 . Registered on 9 August 2016. EudraCT no. 2015-004433-26.

Survival by Histologic Subtype of Malignant Pleural Mesothelioma and the Impact of Surgical Resection on Overall Survival

INTRODUCTION

For the 3 histologic subtypes of malignant pleural mesothelioma (MPM)-epithelioid, sarcomatoid, and biphasic-the magnitude of benefit with surgical management remains underdefined.

MATERIALS AND METHODS

The National Cancer Data Base was queried for newly diagnosed nonmetastatic MPM with known histology. Patients in each histologic group were dichotomized into those receiving gross macroscopic resection versus lack thereof/no surgery. Kaplan-Meier analysis evaluated overall survival (OS) between cohorts; multivariable Cox proportional hazards modeling assessed factors associated with OS. After propensity matching, survival was evaluated for each histologic subtype with and without surgery.

RESULTS

Overall, 4207 patients (68% epithelioid, 18% sarcomatoid, 13% biphasic) met the study criteria. Before propensity matching, patients with epithelioid disease experienced the highest median OS (14.4 months), followed by biphasic (9.5 months) and sarcomatoid (5.3 months) disease; this also persisted after propensity matching (P < .001). After propensity matching, surgery was associated with significantly improved OS for epithelioid (20.9 vs. 14.7 months, P < .001) and biphasic (14.5 vs. 8.8 months, P = .013) but not sarcomatoid (11.2 vs. 6.5 months, P = .140) disease. On multivariable analysis, factors predictive of poorer OS included advanced age, male gender, uninsured status, urban residence, treatment at community centers, and T4/N2 disease (all P < .05). Chemotherapy and surgery were independently associated with improved OS, as was histology (all P < .001).

CONCLUSION

This large investigation evaluated surgical practice patterns and survival by histology for MPM and found that histology independently affects survival. Gross macroscopic resection is associated with significantly increased survival in epithelioid and biphasic, but not sarcomatoid, disease. However, the decision to perform surgery should continue to be individualized in light of available randomized data.

Mismatch Repair Protein Defects and Microsatellite Instability in Malignant Pleural Mesothelioma

INTRODUCTION

Malignant pleural mesothelioma is an aggressive malignancy with limited systemic therapy options. Promising results have been reported with use of anti-programmed cell death 1 therapy; however, its benefits appear to be confined to a subgroup of patients. Microsatellite instability (MSI) results from the inactivation of DNA mismatch repair genes and results in a high tumor mutational burden, a phenomenon that has not been seen with mesothelioma. MSI and protein absence have been shown to correlate in colorectal cancer, such that most centers have adopted immunohistochemistry (IHC) to screen for MSI-high colorectal cancers. We profiled a large cohort of patients with mesothelioma to determine the rate of negative IHC staining results the four common mismatch repair proteins.

DESIGN

A tissue microarray comprising 335 patients with malignant pleural mesothelioma were used. IHC for the four common mismatch repair proteins (mutL homolog 1; PMS1 homolog 2, mismatch repair system component; mutS homolog 2; and mutS homolog 6) was performed. Programmed death ligand 1 IHC staining with the E1L3N clone was also performed. DNA was isolated from IHC equivocal samples and analyzed for microsatellite instability by using the Promega MSI Analysis System (version 1.2, Promega, Madison, WI).

RESULTS

Of the patients profiled, 329 had intact mismatch repair proteins by IHC. Six samples with IHC testing results indicating absent mismatch repair protein were analyzed for MSI and confirmed to be negative. Of the six IHC-negative samples, five were negative for programmed death ligand 1 staining and one sample had more than 5% staining.

CONCLUSION

In this large retrospective series, we were unable to identify any patients with malignant pleural mesothelioma with microsatellite instability. Response to anti-programmed cell death 1-based immunotherapy may be driven by other mechanisms.

Prognostic factors and treatment outcomes of malignant pleural mesothelioma in Eastern Asian patients - A Taiwanese study

BACKGROUND/PURPOSE

There are scarce reports on the prognostic factors and treatment outcomes of patients with malignant pleural mesothelioma (MPM) in Asia. This study aimed to address these matters in a real-world setting.

METHODS

Medical records of patients with histologically proven MPM diagnosed between 1977 and 2016 at the National Taiwan University Hospital were reviewed. Variables including age, gender, performance status, asbestos exposure, smoking history, histology subtype, staging, and treatment received were recorded. All patients were followed until death or March 1st, 2017. Survival and prognostic factors were analyzed by the Kaplan-Meir method and the Cox proportional hazard model.

RESULTS

A total of 93 patients was identified, including 65 men and 28 women. An increasing trend of MPM cases diagnosed was observed in the past 40 years. Stage I/II disease (HR 0.24, 95% CI 0.13-0.46) and epithelioid histology (HR 0.42, 95% CI 0.23-0.75) were associated with favorable prognosis, whereas age ≥70 years (HR 2.66, 95% CI 1.36-5.22) and ECOG ≥2 (HR 5.03, 95% CI 2.69-9.4) were poor prognostic factors. After adjustment for prognostic factors, surgery in stage I-III MPM (HR 0.36, 95% CI 0.15-0.83) and systemic therapy in stage III/IV disease (HR 0.42, 95% CI 0.19-0.94) conferred a survival benefit.

CONCLUSION

This is one of the largest case series of MPM reported in Asia outside of Japan. Prognostic factors in the study population included age, performance status, stage, and histology subtype. Surgery in potentially resectable disease and systemic therapy in advanced MPM confer a survival benefit in Asian patients.

Four immunohistochemical assays to measure the PD-L1 expression in malignant pleural mesothelioma

Immune checkpoint inhibitors (ICIs) targeting the PD-1/PD-L1 pathway are expected to be a novel therapy for combating future increases in numbers of malignant pleural mesothelioma (MPM) patients. However, the PD-L1 expression, which is a predictor of the response to ICIs, is unclear in MPM. We studied the PD-L1 expression using four immunohistochemical assays (SP142, SP263, 28-8 and 22C3) in 32 MPM patients. The PD-L1 expression in tumor cells and immune cells was evaluated to clarify the rate of PD-L1 expression and the concordance among the four assays in MPM. The positivity rate of PD-L1 expression was 53.1% for SP142, 28.1% for SP263, 53.1% for 28-8, and 56.3% for 22C3. Nine cases were positive and 10 were negative for all assays. Discordance among the four assays was found in 13 cases. The concordance rates between SP142 and 22C3 and between 28-8 and 22C3 were the highest (84.4%). The concordance rates between SP263 and the other three assays were low (71.9% to 75.0%). The PD-L1 expression in MPM was almost equivalent for three of the assays. Given the cut-off values set in our study, these findings suggested that these assays, except for SP263, can be used for accurate PD-L1 immunostaining in MPM.

Global trends in mortality from malignant mesothelioma: Analysis of WHO mortality database (1994-2013)

BACKGROUND AND OBJECTIVE

Little is known about the extent to which asbestos use ban has affected global trends in malignant mesothelioma. This study investigated recent global mortality trends of malignant mesothelioma.

METHODS

Data were collected from International Agency for Research on Cancer/World Health Organization mortality database to examine age-standardized, gender-specific mortality rates for malignant mesothelioma (ICD10-C45). Cross-sectional mortality rates (2009-2013) as well as trends over time (1994-2013) were also reported. Gender-specific annual percent change (APC) was calculated to examine trends over time for each country.

RESULTS

Among the 30 countries with highest mesothelioma mortality in men, there is almost 10-fold variation in mortality rates during 2009-2013 ranging from 6.25 per 100 000 for United Kingdom to 0.64 per 100 000 in Portugal; whereas, among the 30 countries with highest mesothelioma mortality in women, there is a 4-fold variation in mortality rates during 2009-2013 ranging from 1.08 per 100 000 for United Kingdom to 0.26 per 100 000 in Ireland. Mortality rates were higher in men compared to women in 32 out of 35 evaluable countries. Among males and over the last 10 years of covered years, mesothelioma mortality was significantly declining in 9 countries (United Kingdom, Sweden, France, Germany, Netherlands, Canada, United States, Australia, and New Zealand); whereas, it was significantly rising in 5 countries (Poland, Spain, China-Hong Kong, Japan, and Republic of Korea). In the remaining countries, APC was stable. Among females and over the last 10 years of covered years, mesothelioma mortality was significantly declining in 1 country only (Italy); whereas, it was significantly rising in 3 countries (Poland, Argentina, and Republic of Korea). In the remaining countries, APC was stable.

CONCLUSIONS

There is a worldwide variability in the burden and trends of mesothelioma mortality; and despite the ban on asbestos in many countries, mesothelioma still represents an important cause of mortality.

Therapeutic potential of targeting S100A11 in malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is an aggressive tumor with an unfavorable prognosis. The standard therapeutic approaches are limited to surgery, chemotherapy, and radiotherapy. Because the consequent clinical outcome is often unsatisfactory, a different approach in MPM treatment is required. S100A11, a Ca²⁺-binding small protein with two EF-hands, is frequently upregulated in various human cancers. Interestingly, it has been found that intracellular and extracellular S100A11 have different functions in cell viability. In this study, we focused on the impact of extracellular S100A11 in MPM and explored the therapeutic potential of an S100A11-targeting strategy. We examined the secretion level of S100A11 in various kinds of cell lines by enzyme-linked immunosorbent assay. Among them, six out of seven MPM cell lines actively secreted S100A11, whereas normal mesothelial cell lines did not secrete it. To investigate the role of secreted S100A11 in MPM, we inhibited its function by neutralizing S100A11 with an anti-S100A11 antibody. Interestingly, the antibody significantly inhibited the proliferation of S100A11-secreting MPM cells in vitro and in vivo. Microarray analysis revealed that several pathways including genes involved in cell proliferation were negatively enriched in the antibody-treated cell lines. In addition, we examined the secretion level of S100A11 in various types of pleural effusions. We found that the secretion of S100A11 was significantly higher in MPM pleural effusions, compared to others, suggesting the possibility for the use of S100A11 as a biomarker. In conclusion, our results indicate that extracellular S100A11 plays important roles in MPM and may be a therapeutic target in S100A11-secreting MPM.

Trimodality Treatment of Malignant Pleural Mesothelioma: An Institutional Review

OBJECTIVE

Malignant pleural mesothelioma (MPM) is a deadly disease with varying treatment options. This study retrospectively describes treatment practices at the University of Washington Medical System from 1980 to 2011, and evaluates the impact of trimodality therapy and radiation (photon and neutron) on survival.

METHODS

A retrospective study was conducted on patients treated for MPM. Univariate and multivariate methods were utilized to evaluate potential factors associated with survival. Treatments received and baseline characteristics were included. Survival analysis of trimodality therapy was performed using a propensity score method to control for baseline characteristics.

RESULTS

Among 78 eligible patients, the median age at diagnosis was 59 years and the median survival was 13.7 months. On multivariate analysis, the significant predictors of improved survival were age, smoking history, location, and receipt of radiation therapy or chemotherapy. In the 48 patients receiving radiation therapy, the difference in survival between neutron therapy and non-neutron therapy patients was not statistically significant: hazard ratio, 1.20 (95% confidence interval, 0.68-2.13), P=0.52. Patients receiving trimodality therapy were more likely to have early-stage disease (60% vs. 30%) and epithelioid histology (86% vs. 58%). In a propensity score-weighted Cox proportional hazards model, trimodality therapy patients had improved overall survival, hazard ratio 0.45, P=0.004, median 14.6 versus 8.6 months.

CONCLUSIONS

Trimodality therapy was significantly associated with prolonged survival in patients with MPM, even when adjusting for baseline patient factors. Radiation therapy was associated with improved survival, but the modality of radiation therapy used was not associated with outcome.

Minor regression and long-time survival (56 months) in a patient with malignant pleural mesothelioma under Viscum album and Helleborus niger extracts-a case report

Malignant pleural mesothelioma (MPM) is a rare cancer with a dismal prognosis. Viscum album extracts (VAE) have strong immune stimulatory properties, cytotoxic effects, can downregulate cancer genes and inhibit angiogenesis. VAE are often used as an adjunct treatment in cancer patients but have rarely been investigated in MPM. Helleborus niger extracts (HNE) have been used in anticancer therapy since antiquity, and also show tumor specific cytotoxic effects. We present a case of a 64-year old woman with epithelioid MPM of the right chest with node involvement (T2N1M0, stage III). Deciding against the recommended radio-chemotherapy, surgery and pleurodesis, she opted for an integrative treatment approach and was treated with VAE and HNE. After 6 weeks' treatment, the pleural and nodal MPM manifestations were reduced by about 15%. Subsequent tumor growth was slow, and the patient remained in good health, enabling her to remain physically active until shortly before her death 56 months after the initial diagnosis. This is a rare case of an MPM patient not receiving any standard anticancer treatment; it still shows an extraordinary long survival and good performance status. We presume that VAE and HNE might had an impact on this clinically relevant outcome and therefore should be further investigated in MPM.

The revised staging system for malignant pleural mesothelioma based on surveillance, epidemiology, and end results database

BACKGROUND

Several staging systems for MPM have been introduced. However, none of them provide perfect survival stratification among heterogeneous patients. The aim of this population-based cohort study was to propose adjustments to current staging system for malignant pleural mesothelioma (MPM).

METHODS

We retrieved MPM data from Surveillance, Epidemiology, and End Results database (1973-2014). Kaplan-Meier method was derived to examine the prognostic effects of tumor, lymph node, metastasis and histology features. Proportional hazards models guided adjustments to stage groupings. The accuracy of staging systems at predicting survival was evaluated by concordance index and bootstrap resampling.

RESULTS

A total of 1110 MPM cases were extracted from SEER. T stage failed to demonstrate survival difference between adjacent categories with the exception of T3 versus T4 (P < 0.001). Patients in M0 had better prognosis than those in M1 (P < 0.001). Exploratory analyses suggested important survival difference for single-versus multiple-site M1 cases (P < 0.001), but not for different metastatic sites (P = 0.286). Histology subtype was a significant prognostic indicator (P < 0.001). Regrouping of TNM and histology combinations resulted in the best concordance index (0.683), compared with UICC 2010 (0.578) and IASLC 2016 (0.585) staging systems. The revised staging system also improved patients distribution (IA:33.8%, IB:17.0%, II: 20.7%, IIIA:10.6%, IIIB: 6.8%, IV:11.1%). Log-rank analyses and calibration plots both demonstrated the new stage achieved optimal survival prediction and discrimination.

CONCLUSION

The revised staging system improved patients distribution and survival stratification for MPM.

Novel ATP-competitive Akt inhibitor afuresertib suppresses the proliferation of malignant pleural mesothelioma cells

Malignant pleural mesothelioma (MPM), an asbestos-related occupational disease, is an aggressive and incurable tumor of the thoracic cavity. Despite recent advances in MPM treatment, overall survival of patients with MPM is very low. Recent studies have implicated that PI3K/Akt signaling is involved in MPM cell survival and development. To investigate the effects of Akt inhibitors on MPM cell survival, we examined the effects of nine selective Akt inhibitors, namely, afuresertib, Akti-1/2, AZD5363, GSK690693, ipatasertib, MK-2206, perifosine, PHT-427, and TIC10, on six MPM cell lines, namely, ACC-MESO-4, Y-MESO-8A, MSTO-211H, NCI-H28, NCI-H290, and NCI-H2052, and a normal mesothelial cell line MeT-5A. Comparison of IC₅₀ values of the Akt inhibitors showed that afuresertib, an ATP-competitive specific Akt inhibitor, exerted tumor-specific effects on MPM cells. Afuresertib significantly increased caspase-3 and caspase-7 activities and apoptotic cell number among ACC-MESO-4 and MSTO-211H cells. Moreover, afuresertib strongly arrested the cell cycle in the G₁ phase. Western blotting analysis showed that afuresertib increased the expression of p21^WAF1/CIP1 and decreased the phosphorylation of Akt substrates, including GSK-3β and FOXO family proteins. These results suggest that afuresertib-induced p21 expression promotes G₁ phase arrest by inducing FOXO activity. Furthermore, afuresertib significantly enhanced cisplatin-induced cytotoxicity. Interestingly, results of gene set enrichment analysis showed that afuresertib modulated the expression E2F1 and MYC, which are associated with fibroblast core serum response. Together, these results suggest that afuresertib is a useful anticancer drug for treating patients with MPM.

Immunotherapy for malignant pleural mesothelioma: current status and future directions

Malignant pleural mesothelioma (MPM) has been marked historically by poor prognosis. Current standard of care for this deadly disease results in sub-optimal improvements in overall survival (OS), which has prompted researchers to explore innovative treatment alternatives. Immunotherapy is an emerging therapeutic modality that harnesses the power of the human immune system. In this review, we summarize the different methods of immunotherapy for malignant pleural mesothelioma. Using ClinicalTrials.gov we searched the terms "immunotherapy" and "immune therapy" combined with "pleural mesothelioma". Our search yielded 75 trials, among which 37 trials met our specific criteria. Our search identified immune checkpoint blockade, immunotoxin therapy, anticancer vaccines, oncolytic viral therapy, and adoptive cell therapy as the most common and pertinent methods of immunotherapy currently being assessed in clinical trials. We have reviewed the most up-to-date clinical trials involving immunotherapeutic approaches for the treatment of malignant pleural mesothelioma. In addition to highlighting some of the successes of immunotherapy, we also have identified limitations that must be overcome to improve the efficacy of these therapies.

Life Expectancy in Pleural and Peritoneal Mesothelioma

Background. Mesothelioma is a rare cancer with a historically dire prognosis. We sought to calculate life expectancies for patients with pleural or peritoneal mesothelioma, both at time of diagnosis and several years later, and to examine whether survival has improved in recent years. Methods. Data on 10,258 pleural and 1,229 peritoneal patients from the SEER US national cancer database, 1973-2011, were analyzed using the Cox proportional hazards regression model. Results. The major factors related to survival were age, sex, stage, grade, histology, and treatment. Survival improved only modestly over the study period: 0.5% per year for pleural and 2% for peritoneal. Conclusions. Life expectancies were markedly reduced from normal, even amongst 5-year survivors with the most favorable characteristics and treatment options.

Mesothelioma in the United States: a Surveillance, Epidemiology, and End Results (SEER)-Medicare investigation of treatment patterns and overall survival

INTRODUCTION

Mesothelioma is a rare malignancy typically associated with exposure to asbestos and poor survival. The purpose of this investigation was to describe mesothelioma patient characteristics, treatment patterns, and overall survival (OS) utilizing the National Cancer Institute's Surveillance, Epidemiology, and End Results-Medicare database.

MATERIALS AND METHODS

Patients in this study were diagnosed with malignant mesothelioma of the pleura or peritoneum between January 1, 2005 and December 31, 2009 with follow-up for survival through December 31, 2010. We examined both patient and tumor characteristics at time of diagnosis and subsequent treatment patterns (surgery, radiation, and chemotherapy). Among patients treated with chemotherapy, we determined chemotherapy regimen and OS by line of therapy.

RESULTS

Of the 1,625 patients considered eligible for this investigation, the median age at diagnosis was 78 years. Nearly a third of patients (30%) had surgery as part of their treatment and 45% were given chemotherapy. The median OS was 8 months (range 1-69 months). Among chemotherapy patients, the most commonly (67%) prescribed regimen for first-line therapy was cisplatin or carboplatin (Ca/Ci) combined with pemetrexed (Pe). Among those prescribed Ca/Ci + Pe as first-line therapy, retreatment with Ca/Ci + Pe (28%) or treatment with gemcitabine (30%) were the most common second-line therapies. Median OS for those receiving first-line chemotherapy was 7 months, and among those receiving second-line therapy median OS was extended an additional 5 months.

CONCLUSION

Irrespective of surgical resection, mesothelioma patients receiving some form of chemotherapy survived longer than patients who did not, with an additional survival benefit among those patients receiving multimodal treatment.

Impact of Age on Long-Term Outcomes of Surgery for Malignant Pleural Mesothelioma

BACKGROUND

Although malignant pleural mesothelioma (MPM) is generally a disease associated with more advanced age, the association of age, treatment, and outcomes has not been well-characterized. We evaluated the impact of age on outcomes in patients with MPM to provide data for use in the treatment selection process for elderly patients with potentially resectable disease.

PATIENTS AND METHODS

Overall survival (OS) of patients younger than 70 and 70 years or older with Stage I to III MPM who underwent cancer-directed surgery or nonoperative management in the Surveillance, Epidemiology, and End Results database (2004-2010) was evaluated using multivariable Cox proportional hazard models and propensity score-matched analysis.

RESULTS

Cancer-directed surgery was used in 284 of 879 (32%) patients who met inclusion criteria, and was associated with improved OS in multivariable analysis (hazard ratio, 0.71; P = .001). Cancer-directed surgery was used much less commonly in patients 70 years and older compared with patients younger than 70 years (22% [109/497] vs. 46% [175/382]; P < .001), but patients 70 years and older had improved 1-year (59.4% vs. 37.9%) and 3-year (15.4% vs. 8.0%) OS compared with nonoperative management. The benefit of surgery in patients 70 years and older was observed even after propensity score-matched analysis was used to control for selection bias.

CONCLUSION

Surgical treatment is associated with improved survival compared with nonoperative management for both patients younger than 70 years and patients aged 70 years or older.

Simian virus 40 may be associated with developing malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is associated with a history of heavy, long-term exposure to asbestos. However, MPM may also be associated with simian virus 40 (SV40), a polyomavirus. The association between SV40 and MPM remains unclear. The present study was conducted in order to investigate the proportion of SV40 presence in the histological specimens of Vietnamese patients with MPM. Histological specimens were obtained from 45 patients (19 men and 26 women) with MPM at the Pham Ngoc Thach Hospital in Ho Chi Minh City, Vietnam. The specimens were processed and examined in order to detect the presence of the SV40 large T antigen (SV40 Tag) expression using immunohistochemistry. Of the 45 patients, 23 (51%) were epithelioid, 7 (16%) were biphasic, 6 (13%) were sarcomatoid, 4 (9%) were desmoplastic, 4 (9%) were well-differentiated papillary and 1 (2%) was the anaplastic subtype. In total, 9/45 patients (20%) demonstrated SV40 Tag expression. The proportion of patients that demonstrated SV40 Tag expression was not significantly different between the epithelioid subtype and the other subtypes (22 vs. 18%; P=1.000) or between the patients with stage IV disease and other stages (20 vs. 20%; P=1.000). The median survival time was not significantly different between the patients with or without SV40 Tag expression (196 vs. 236 days, P=0.8949). In summary, a 5th of the Vietnamese patients with MPM were associated with infection with SV40. SV40 may be a potential cause of MPM in Vietnam and this potential association requires additional studies.

Relapse pattern and second-line treatment following multimodality treatment for malignant pleural mesothelioma

OBJECTIVES

To analyse the relapse pattern and influence of second-line treatment after recurrence of malignant pleural mesothelioma (MPM) in patients who had previously undergone multimodality treatment.

METHODS

Between September 1999 and December 2013, 136 patients underwent macroscopic complete resection (MCR) by extrapleural pneumonectomy after induction chemotherapy for MPM. We analysed 106 patients who presented with recurrent disease until October 2014. Data were retrieved from our mesothelioma database, with additional information regarding precise localization gathered by reviewing the imaging and medical records.

RESULTS

The overall recurrence rate was 78% (106/136 patients). The median freedom from recurrence was 9 months after surgery [95% confidence interval (95% CI) 7-10]. Local recurrence only was observed in 33 patients (31%), distant metastases only in 27 patients (26%) and simultaneous distant and local recurrence in 46 patients (43%). Local recurrence was observed significantly less frequently in patients having received adjuvant radiotherapy (19 vs 47%, P = 0.003), but there was no significant impact on overall survival (OS) [radiation: 22 months (95% CI 19-24); no-radiation: 23 months (95% CI 18-27), P = 0.6]. The median OS was 22 months (95% CI 21-24), median post-recurrence survival (PRS) was 7 months (95% CI 5-9) and patients with local recurrence only survived significantly longer (12 months, 95% CI 8-16) compared with patients with distant recurrence only (5 months, 95% CI 2-8) or distant plus local relapse (6 months, 95% CI 3-9; P = 0.04). A total of 78 patients received a second-line therapy after tumour recurrence: chemotherapy (n = 48), local radiotherapy (n = 9), surgery (n = 10) or a combination thereof (n = 11). Patients undergoing second-line treatment survived significantly longer compared with patients not receiving therapy (P < 0.0005). The median PRS after surgery was significantly longer than that of patients receiving chemo-, radio- or chemo-radiotherapy (P = 0.04).

CONCLUSIONS

Local recurrence of MPM remains the most frequent type of relapse even after multimodality treatment including MCR. In the present cohort, active treatment seems beneficial to the patient since surgical excision of local tumour relapse has good long-term outcome in selected patients. Thus, second-line treatment may prolong PRS; however, these results need to be confirmed in a prospective manner.

Deletion status of p16 in effusion smear preparation correlates with that of underlying malignant pleural mesothelioma tissue

Differentiating malignant pleural mesothelioma (MPM) cells morphologically from reactive mesothelial hyperplasia cells is problematic. Homozygous deletion (HD) of p16 (CDKN2A), detected by FISH, is a good marker of malignancy and is useful to differentiate between these cells. However, the correlation between the p16 status of effusion smears and that of the underlying MPM tissues has not been investigated. We used p16‐specific FISH to investigate 20 cases of MPM from which both effusion cytologic smears and histologic specimens were available. In five cases, histologic specimens included both an invasive component and surface mesothelial proliferation. In 14 cases (70%), MPM cells in both tissue sections and effusion smears were p16 HD‐positive. Conversely, MPM cells in the remaining six tumors (30%) were p16 HD‐negative in both tissue sections and effusion smears. For all five MPM cases with surface mesothelial proliferations and invasive components, the effusion smears, surface mesothelial proliferations, and invasive MPM components all displayed p16 deletion. Moreover, the extent to which p16 was deleted in smears highly correlated with the extent of p16 deletion in tissues. The p16 deletion percentages were also similar among smears, tissue surface proliferations, and invasive components. In cases with clinical and radiologic evidence of a diffuse pleural tumor, detection of p16 deletion in cytologic smear samples may permit MPM diagnosis without additional tissue examination. However, the absence of p16 deletion in cytologic smear samples does not preclude MPM.

Epithelioid pleural mesothelioma concurrently associated with miliary pulmonary metastases and minimal change nephrotic syndrome - A hitherto undescribed case

Malignant pleural mesothelioma (MPM) is the aggressive disease typically spreading along the pleural surface and encasing the lung, leading to respiratory failure or cachexia. Rare cases with atypical clinical manifestation or presentation have been reported in MPM. We experienced a unique case of MPM concurrently associated with miliary pulmonary metastases and nephrotic syndrome. A 73-year-old Japanese man with past history of asbestos exposure was referred to our hospital for the investigation of the left pleural effusion. Chest computed tomography showed thickening of the left parietal pleura. Biopsy specimen of the pleura showed proliferating epithelioid tumor cells, leading to the pathological diagnosis of epithelioid MPM with the aid of immunohistochemistry. After the diagnosis of MPM, chemotherapy was performed without effect. Soon after the clinical diagnosis of progressive disease with skull metastasis, edema and weight gain appeared. Laboratory data met the criteria of nephrotic syndrome, and renal biopsy with electron microscopic examination revealed the minimal change disease. Steroid therapy was started but showed no effect. Around the same time of onset of nephrotic syndrome, multiple miliary lung nodules appeared on chest CT. Transbronchial biopsy specimen of the nodules showed the metastatic MPM in the lung. The patient died because of the worsening of the general condition. To our knowledge, this is the first case of MPM concurrently associated with multiple miliary pulmonary metastases and nephrotic syndrome.

Frequency of Surgery in Black Patients with Malignant Pleural Mesothelioma

INTRODUCTION

Malignant Pleural Mesothelioma (MPM) is a rare disease, even less frequently described in minority patients. We used a large population-based dataset to study the role of race in MPM presentation, treatment, and survival.

METHODS

All cases of pathologically proven MPM were identified in the Surveillance, Epidemiology, and End Results (SEER) database. Age, sex, diagnosis year, stage, cancer-directed surgery, radiation, and vital status were analyzed according to self-reported race (black or white).

RESULTS

There were 13,046 white and 688 black MPM patients (incidence: 1.1 per 100,000 whites; 0.5 per 100,000 blacks; age-adjusted, p = 0.01). Black patients were more likely to be female, younger, and with advanced stage and less likely to undergo cancer-directed surgery than whites, after adjustment by stage. On multivariable analysis, younger age and having surgery were associated with longer survival for both cohorts; female gender (HR 0.82 (0.77-0.88)) and early stage at diagnosis (HR 0.83 (0.76-0.90)) were predictive of longer survival in white, but not in black, patients.

CONCLUSIONS

Surgery was associated with improved survival for both black and white MPM patients. However, black patients were less likely to undergo cancer-directed surgery. Increased surgical intervention in MPM black patients with early stage disease may improve their survival.

Impact of mesothelioma histologic subtype on outcomes in the Surveillance, Epidemiology, and End Results database

BACKGROUND

This study was conducted to determine how malignant pleural mesothelioma (MPM) histology was associated with the use of surgery and survival.

METHODS

Overall survival of patients with stage I-III epithelioid, sarcomatoid, and biphasic MPM in the Surveillance, Epidemiology, and End Results database from 2004-2010 was evaluated using multivariate Cox proportional hazards models.

RESULTS

Of 1183 patients who met inclusion criteria, histologic subtype was epithelioid in 811 patients (69%), biphasic in 148 patients (12%), and sarcomatoid in 224 patients (19%). Median survival was 14 mo in the epithelioid group, 10 mo in the biphasic group, and 4 mo in the sarcomatoid group (P < 0.01). Cancer-directed surgery was used more often in patients with epithelioid (37%, 299/811) and biphasic (44%, 65/148) histologies as compared with patients with sarcomatoid histology (26%, 58/224; P < 0.01). Among patients who underwent surgery, median survival was 19 mo in the epithelioid group, 12 mo in the biphasic group, and 4 mo in the sarcomatoid group (P < 0.01). In multivariate analysis, surgery was associated with improved survival in the epithelioid group (hazard ratio [HR] 0.72; P < 0.01) but not in biphasic (HR 0.73; P = 0.19) or sarcomatoid (HR 0.79; P = 0.18) groups.

CONCLUSIONS

Cancer-directed surgery is associated with significantly improved survival for MPM patients with epithelioid histology, but patients with sarcomatoid and biphasic histologies have poor prognoses that may not be favored by operative treatment. The specific histology should be identified before treatment, so that surgery can be offered to patients with epithelioid histology, as these patients are most likely to benefit.

Mesothelioma patients with germline BAP1 mutations have 7-fold improved long-term survival

BRCA1-associated protein-1 (BAP1) mutations cause a new cancer syndrome, with a high rate of malignant mesothelioma (MM). Here, we tested the hypothesis that MM associated with germline BAP1 mutations has a better prognosis compared with sporadic MM. We compared survival among germline BAP1 mutation MM patients with that of all MM (N = 10 556) recorded in the United States Surveillance, Epidemiology, and End Results (SEER) data from 1973 to 2010. We identified 23 MM patients--11 alive--with germline BAP1 mutations and available data on survival. Ten patients had peritoneal MM, ten pleural MM and three MM in both locations. Thirteen patients had one or more malignancies in addition to MM. Actuarial median survival for the MM patients with germline BAP1 mutations was 5 years, as compared with <1 year for the median survival in the United States SEER MM group. Five-year survival was 47%, 95% confidence interval (24-67%), as compared with 6.7% (6.2-7.3%) in the control SEER group. Analysis of the pooled cohort of germline BAP1 mutation MM showed that patients with peritoneal MM (median survival of 10 years, P = 0.0571), or with a second malignancy in addition to MM (median survival of 10 years, P = 0.0716), survived for a longer time compared with patients who only had pleural MM, or MM patients without a second malignancy, respectively. In conclusion, we found that MM patients with germline BAP1 mutations have an overall 7-fold increased long-term survival, independently of sex and age. Appropriate genetic counseling and clinical management should be considered for MM patients who are also BAP1 mutation carriers.

Women with malignant pleural mesothelioma have a threefold better survival rate than men

BACKGROUND

Many studies have reported that women with malignant pleural mesothelioma (MPM) experience longer survival compared with men, whereas others have not. To date, no large population-based studies have evaluated MPM outcome and its determinants in female patients.

METHODS

All pathologically confirmed cases of MPM in the Surveillance, Epidemiology and End Results database from 1973 to 2009 were evaluated. Age, year of diagnosis, race, stage, cancer-directed surgery, radiation, and vital status were analyzed according to gender. Cox proportional hazard models were derived to assess the association between prognostic factors and survival.

RESULTS

There were 14,228 cases of MPM, of which 3,196 (22%) were women. Despite similar baseline characteristics for both genders, 5-year survival was 13.4% in women and 4.5% in men (p < 0.0001). The effect of female gender on survival persisted when stratified by age (dichotomized at 50 years), stage, or race, but differed depending on treatment. Even when adjusted for age, stage, race, and treatment, female MPM patients experienced longer survival than men (hazard ratio = 0.78; 95% confidence interval 0.75 to 0.82).

CONCLUSIONS

This large data set confirms that although MPM is less common in women, they present with similar stage and are offered similar treatment options compared with men. Nevertheless, survival is far better in women compared with men, independent of confounders such as age, stage, and treatment. Differences in asbestos exposure, tumor biology, and the impact of circulating hormones on host response must be investigated to understand this survival advantage and improve prognosis for patients of both genders.

Clinical significance of epithelial-mesenchymal transition-associated markers in malignant pleural mesothelioma

Epithelioid tumors with aggressive behavior have been reported; however, the epithelioid type of malignant pleural mesothelioma (MPM) has a less aggressive behavior. Few studies have evaluated the prognostic value of epithelial-mesenchymal transition (EMT) markers in MPM. We hypothesized that mesenchymal characteristics might predominate in the tumors. Tumor specimens were collected from 33 consecutive patients. We analyzed the EMT expression levels in tumor samples by an immunohistochemical analysis. Positive expression of E-cadherin, γ-catenin, vimentin, fibronectin, Twist and YB-1 was observed in 25, 14, 21, 1, 19 and 18 patients, respectively. No significant association between these markers and the clinicopathological characteristics was found. γ-Catenin demonstrated a trend towards decreased expression in sarcomatoid tumors compared to epithelioid tumors. On the other hand, a trend was noted towards higher expression of vimentin, Twist and YB-1 in sarcomatoid tumors. The survival curves demonstrated that the patients with negative γ-catenin and positive Twist staining had a tendency to have a worse prognosis. Although the individual proteins might not significantly affect the progression of MPM, the combination of γ-catenin and Twist staining can predict the prognosis of patients with MPM.

Clinicopathologic Characteristics of Malignant Mesotheliomas Arising in Patients With a History of Radiation for Hodgkin and Non-Hodgkin Lymphoma

Purpose

Studies have reported an association between pleural diffuse malignant mesothelioma (PDMM) and chest radiation for lymphoma. The clinicopathologic characteristics of malignant mesotheliomas arising in these patients have not been established.

Patients and Methods

We studied 1,618 consecutive patients diagnosed with pleural PDMM from July 1993 to February 2008 and identified patients with a history of radiation for Hodgkin and non-Hodgkin lymphoma. We evaluated the histology in the surgical resection specimens and compared clinicopathologic features with overall survival.

Results

We identified 22 patients who developed PDMM after chest radiation as part of their treatment for lymphoma (mean latency time, 21.4 years; 95% CI, 17.0 to 25.8 years). Asbestos bodies in lymphoma-associated PDMM were lower than in asbestos-associated PDMM (median count, 15 v 325 bodies, respectively; P < .001) and similar to an unexposed control group (median count, 15 v 10 bodies, respectively; P = .6). Seventeen lymphoma-associated PDMMs (77%) were epithelioid and five (23%) were biphasic. Seven PDMMs (32%) had unusual histologies (pleomorphic, myxoid, clear cell, and signet ring cell). Patients with lymphoma-associated PDMM were younger than patients with asbestos-associated PDMM (median age, 45 v 64 years, respectively; P < .001) and had a significantly longer overall survival time (median, 32.5 v 12.7 months, respectively; P = .018). In multivariate analysis, independent favorable predictors for overall survival were history of prior radiation (P = .022), female sex (P < .001), age ≤ 65 years (P = .005), cytoreductive surgery (P < .001), and epithelioid histology (P < .001).

Conclusion

Patients with lymphoma-associated PDMM are likely to have unusual histologic features, are significantly younger, and seem to have a longer overall survival compared with patients with asbestos-associated PDMM.