Survival analysis and development of a prognostic nomogram for patients with malignant mesothelioma in different anatomic sites

Background

Malignant mesothelioma (MMe) is a rare and fatal cancer with a poor prognosis. Our study aimed to compare the overall survival (OS) of MMe patients across various sites and develop a prognostic model to provide a foundation for individualized management of MMe patients.

Methods

From the Surveillance, Epidemiology, and End Results (SEER) database, 1,772 individuals with malignant mesothelioma (MMe) were identified. The X-tile software was used to identify the optimal cut-off point for continuous variables. The Kaplan–Meier method was employed to compare the survival of MMe across different sites. The Cox proportional hazards model was applied to identify the independent risk factors of overall survival (OS) and a nomogram was constructed.

Results

In the survival analysis, MMe originating from the reproductive organs and hollow organs showed a relatively better prognosis than those originating from soft tissue, solid organs, and pleura. Age, gender, location, histological type, grade of differentiation, extent of disease, lymph node status, lymph node ratio (LNR), and chemotherapy were all found to be independent risk variables for the prognosis of MMe patients (P<0.05) in a multivariate Cox analysis and were included in the construction of nomogram. In the training and testing sets, the C-index of the nomogram was 0.701 and 0.665, respectively, and the area under the ROC curve (AUROC) of the 1-, 3-, and 5-year overall survival rate was 0.749, 0.797, 0.833 and 0.730, 0.800, 0.832, respectively. The calibration curve shows that the nomogram is well-calibrated.

Conclusions

This is the first research to examine the prognosis of MMe patients based on the location. However, previous studies often focused on malignant pleural mesothelioma or malignant peritoneal mesothelioma with high incidence. Furthermore, a nomograph with good prediction efficiency was established according to the variables that influence patient survival outcomes, which provides us with a reference for clinical decision-making.

A combination of intrinsic and extrinsic features improves prognostic prediction in malignant pleural mesothelioma

BACKGROUND

Malignant pleural mesothelioma (MPM) is a lung pleural cancer with very poor disease outcome. With limited curative MPM treatment available, it is vital to study prognostic biomarkers to categorise different patient risk groups.

METHODS

We defined gene signatures to separately characterise intrinsic and extrinsic features, and investigated their interactions in MPM tumour samples. Specifically, we calculated gene signature scores to capture the downstream pathways of major mutated driver genes (BAP1, NF2, SETD2 and TP53) as tumour-intrinsic features. Similarly, we inferred the infiltration levels for major immune cells in the tumour microenvironment to characterise tumour-extrinsic features. Lastly, we integrated these features with clinical factors to predict prognosis in MPM.

RESULTS

The gene signature scores were more prognostic than the corresponding genomic mutations, mRNA and protein expression. High immune infiltration levels were associated with prolonged survival. The integrative model indicated that tumour features provided independent prognostic values than clinical factors and were complementary with each other in survival prediction.

CONCLUSIONS

By using an integrative model that combines intrinsic and extrinsic features, we can more correctly predict the clinical outcomes of patients with MPM.

Global magnitude and temporal trend of mesothelioma burden along with the contribution of occupational asbestos exposure in 204 countries and territories from 1990 to 2019: Results from the Global Burden of Disease Study 2019

Understanding the burden of mesothelioma with the contribution of occupational asbestos exposure globally provides essential foundations for cancer control, policy decisions and resource allocation. Globally, 34,511 incident cases, 29,251 deaths and 668,104 disability-adjusted life years (DALYs) of mesothelioma were estimated in 2019. The age-standardized rates of incidence, mortality and DALYs all showed a slightly declining trend over the past 30 years, but the latest absolute number of mesothelioma burden almost doubled since 1990. The burden rate decreased among the population aged under 70 years, but increased among the population aged over 80 years, especially in the High socio-demographic index (SDI) region. The burden rate of mesothelioma attributable to asbestos exposure was positively associated with SDI at the national level. This study depicted a continuous increase in mesothelioma burden globally over the past 30 years. Controlling occupational asbestos exposure will reduce the mesothelioma burden, especially for higher SDI regions.

Concurrent alcoholic cirrhosis and malignant peritoneal mesothelioma in a patient: A case report

BACKGROUND

Malignant peritoneal mesothelioma (MPM) originates from the mesothelial and subcutaneous cells of the abdominal cavity. Its diagnose is difficult due to its nonspecific and vague symptoms, and it should be differentiated from alcoholic cirrhosis and liver and pancreatic cancers. Misdiagnosis and missed diagnosis can easily occur when MPM presents with other diseases. To the best of our knowledge, no case of MPM concurrent with alcoholic cirrhosis has been reported.

CASE SUMMARY

A 63-year-old man presented to our hospital with abdominal distension for 20days. He had a history of alcohol consumption for nearly 30 years and no history of special drug use or toxic exposure. After treatment for alcoholic cirrhosis in a community hospital, his symptoms did not improve significantly. The patient underwent exploratory laparotomy and surgical resection. Pathologic examination showed an epithelioid MPM. He was treated with chemotherapy and intraperitoneal hyperthermic perfusion after surgery. Currently, he is in a stable condition and tumor recurrence has not occurred.

CONCLUSION

Misdiagnosis and missed diagnosis of MPM can easily occur because of its insidious onset. Therefore, there is a need to understand. MPM in clinical practice, make the correct diagnosis, and provide timely and effective treatment.

Silencing VDAC1 to Treat Mesothelioma Cancer: Tumor Reprograming and Altering Tumor Hallmarks

Mesothelioma, an aggressive cancer with a poor prognosis, is linked to asbestos exposure. However, carbon nanotubes found in materials we are exposed to daily can cause mesothelioma cancer. Cancer cells reprogram their metabolism to support increased biosynthetic and energy demands required for their growth and motility. Here, we examined the effects of silencing the expression of the voltage-dependent anion channel 1 (VDAC1), controlling the metabolic and energetic crosstalk between mitochondria and the rest of the cell. We demonstrate that VDAC1 is overexpressed in mesothelioma patients; its levels increase with disease stage and are associated with low survival rates. Silencing VDAC1 expression using a specific siRNA identifying both mouse and human VDAC1 (si-m/hVDAC1-B) inhibits cell proliferation of mesothelioma cancer cells. Treatment of xenografts of human-derived H226 cells or mouse-derived AB1 cells with si-m/hVDAC1-B inhibited tumor growth and caused metabolism reprogramming, as reflected in the decreased expression of metabolism-related proteins, including glycolytic and tricarboxylic acid (-)cycle enzymes and the ATP-synthesizing enzyme. In addition, tumors depleted of VDAC1 showed altered microenvironments and inflammation, both associated with cancer progression. Finally, tumor VDAC1 silencing also eliminated cancer stem cells and induced cell differentiation to normal-like cells. The results show that silencing VDAC1 expression leads to reprogrammed metabolism and to multiple effects from tumor growth inhibition to modulation of the tumor microenvironment and inflammation, inducing differentiation of malignant cells. Thus, silencing VDAC1 is a potential therapeutic approach to treating mesothelioma.

Localized Malignant Peritoneal Mesothelioma (LMPeM) in Women: A Clinicopathologic Study of 18 Cases

Localized malignant peritoneal mesothelioma is a rare tumor with limited information in the literature. In this study, we present our experience with 18 cases seen in our hospital over a period of 43 years (1978 to 2021). Patients' median age was 55 years (y) (range: 33 to 79 y) and most of them were Caucasians. Patients presented with abdominal pain (11), ascites and right leg swelling (1), abdominal mass (1), and as incidental finding (1). Thirty percent of patients reported asbestos exposure, and all patients with available information had family history of tumors; a third had personal history of tumors. Seventy-seven percent had some form of abdominopelvic surgery and/or inflammatory process. Most cases had microscopic features typically seen in malignant mesothelioma; however, some cases had confounding features such as signet-ring cells, spindle cells, clear cell changes, and adenomatoid tumor-like appearance. BAP-1 by immunohistochemistry was lost in 1/3 cases. Only 1 patient underwent genetic testing and had an MSH2 germline mutation. Homozygous deletion of CDKN2A by FISH was not found in 1 tested case, although next-generation sequencing identified a CDKN2A pathogenic mutation. 16/18 (88%) had surgical treatment, and some also received adjuvant chemotherapy. The mean overall survival (OS) of our patients was 80.4 months (95% confidence interval: 54.3-106.52); the 3-year OS was 79%, while the 5-year OS was 52.6%. Fifty-three percent of patients had recurrences and 20% had tumor progression. Although the limited sample precludes definitive conclusions, small tumor size, low-grade cytology, and low mitotic index appeared to be associated with an indolent behavior.

Novel Insights Into Mesothelioma Therapy: Emerging Avenues and Future Prospects

Malignant mesothelioma is a rare and aggressive cancer that develops in the thin layer surrounding the mesothelium and is mainly caused by asbestos exposure. Despite improvements in patient prognosis with conventional cancer treatments, such as surgery, chemotherapy, and radiotherapy, there are still no curative treatment modalities for advanced disease. In recent years, new therapeutic avenues have been explored. Improved understanding of the mechanisms underlying the dynamic tumor interaction with the immune system has led to the development of immunotherapeutic approaches. Numerous recent clinical trials have shown a desire to develop more effective treatments that can be used to fight against the disease. Immune checkpoint inhibitors, oncolytic adenoviruses, and their combination represent a promising strategy that can be used to synergistically overcome immunosuppression in the mesothelioma tumor microenvironment. This review provides a synthesized overview of the current state of knowledge on new therapeutic options for mesothelioma with a focus on the results of clinical trials conducted in the field.

Repurposing therapeutics for malignant pleural mesothelioma (MPM) - Updates on clinical translations and future outlook

INTRODUCTION

Malignant pleural mesothelioma (MPM) is a rare malignancy affecting the mesothelial cells in the pleural lining surrounding the lungs. First approved chemotherapy against MPM was a platinum/antifolate (cisplatin/pemetrexed) (2003). Since then, no USFDA approvals have gone through for small molecules as these molecules have not been proven to be therapeutically able in later stages of clinical studies. An alternative to conventional chemotherapy can be utilization of monoclonal antibodies, which are proven to improve patient survival significantly as compared to conventional chemotherapy (Nivolumab + Ipilimumab, 2020).

AREA COVERED

Drug repurposing has been instrumental in drug discovery for rare diseases such as MPM and multiple repositioned small molecule therapies and immunotherapies are currently being tested for its applicability in MPM management. This article summarizes essential breakthroughs along the pre-clinical and clinical developmental stages of small molecules and monoclonal antibodies for MPM management.

EXPERT OPINION

For rare diseases such as malignant pleural mesothelioma, a drug repurposing strategy can be adapted as it eases the financial burden on pharmaceutical companies along with fast-tracking development. With the rise of multiple small molecule repurposed therapies and innovations in localized treatment, MPM therapeutics are bound to be more effective in this decade.

Do Carbon Nanotubes and Asbestos Fibers Exhibit Common Toxicity Mechanisms?

During the last two decades several nanoscale materials were engineered for industrial and medical applications. Among them carbon nanotubes (CNTs) are the most exploited nanomaterials with global production of around 1000 tons/year. Besides several commercial benefits of CNTs, the fiber-like structures and their bio-persistency in lung tissues raise serious concerns about the possible adverse human health effects resembling those of asbestos fibers. In this review, we present a comparative analysis between CNTs and asbestos fibers using the following four parameters: (1) fibrous needle-like shape, (2) bio-persistent nature, (3) high surface to volume ratio and (4) capacity to adsorb toxicants/pollutants on the surface. We also compare mechanisms underlying the toxicity caused by certain diameters and lengths of CNTs and asbestos fibers using downstream pathways associated with altered gene expression data from both asbestos and CNT exposure. Our results suggest that indeed certain types of CNTs are emulating asbestos fiber as far as associated toxicity is concerned.

Unexplained Pleural Effusion Leads to the Revelation of a Malignant Mesothelioma: A Case Report

Malignant mesothelioma is a rare and aggressive cancer that usually affects subjects with prior asbestos exposure, a major risk factor that has been widely known as carcinogenic, and its use is now controlled if not banned in many areas of the world. Malignant mesothelioma originates from mesothelial surface cells covering the serous cavities, and the pleura is its most common site. Malignant pleural mesothelioma (MPM) typically presents with pleural effusion and chest wall pain with wide pleural thickening at radiological investigation. Although the histological examination along with immunohistochemistry helps yield the diagnosis, clinicians and experts face many challenges in diagnosing malignant mesothelioma not only due to the rarity of the disease but also due to the similarities that the disease share with other malignancies.

Here, we report a case of a 55-year-old male patient with a history of chronic asbestos work exposure for 12 years who initially presented with unexplained pleural effusion and chest wall pain and was lost to follow-up but came back later with a worsening clinical state. This case is specially presented to raise awareness against cases of unexplained pleural effusion and chest pain.

Inflammation of the Pleural Cavity: A Review on Pathogenesis, Diagnosis and Implications in Tumor Pathophysiology

Pleural effusions are a common respiratory condition with many etiologies. Nonmalignant etiologies explain most pleural effusions and despite being nonmalignant, they can be associated with poor survival; thus, it is important to understand their pathophysiology. Furthermore, diagnosing a benign pleural pathology always harbors the uncertainty of a false-negative diagnosis for physicians and pathologists, especially for the group of non-specific pleuritis. This review aims to present the role of the inflammation in the development of benign pleural effusions, with a special interest in their pathophysiology and their association with malignancy.

Current Management and Future Perspective in Pleural Mesothelioma

Pleural mesothelioma is an aggressive malignancy arising from pleural mesothelial cell lining, predominantly associated with prior exposure to asbestos. The ban on asbestos use has led to its lower incidence in many countries, but globally the disease burden is expected to rise. Therefore, well-planned research is needed to develop more effective, tolerable and affordable drugs. The development of novel treatment has been too slow, with only two regimens of systemic therapy with robust phase 3 data approved formally to date. The treatment scenario for resectable disease remains controversial. However, recent developments in the understanding of disease and clinical trials have been encouraging, and may add better treatment options in the coming years. In this review, we discuss the current treatment options for pleural mesothelioma and shed light on some recent studies and ongoing trials.

Incidence, treatment and survival of malignant pleural and peritoneal mesothelioma: a population-based study

INTRODUCTION

Malignant mesothelioma (MM) is an aggressive cancer that primarily arises from the pleura (MPM) or peritoneum (MPeM), mostly due to asbestos exposure. This study reviewed the Dutch population-based incidence, treatment and survival since the national ban on asbestos in 1993.

MATERIALS AND METHODS

Patients with MPM or MPeM diagnosed from 1993 to 2018 were selected from the Dutch cancer registry. Annual percentage change (APC) was calculated for (age-specific and sex-specific) revised European standardised incidence rates (RESR). Treatment pattern and Kaplan-Meier overall survival analyses were performed.

RESULTS

In total, 12 168 patients were included in the study. For male patients younger than 80 years, the MM incidence significantly decreased in the last decade (APC ranging between -9.4% and -1.8%, p<0.01). Among both male and female patients aged over 80 years, the incidence significantly increased during the entire study period (APC 3.3% and 4.6%, respectively, p<0.01). From 2003 onwards, the use of systemic chemotherapy increased especially for MPM (from 9.3% to 39.4%). Overall, 62.2% of patients received no antitumour treatment. The most common reasons for not undergoing antitumour treatment were patient preference (42%) and performance status (25.6%). The median overall survival improved from 7.3 (1993-2003) to 8.9 (2004-2011) and 9.3 months from 2012 to 2018 (p<0.001).

CONCLUSION

The peak of MM incidence was reached around 2010 in the Netherlands, and currently the incidence is declining in most age groups. The use of systemic chemotherapy increased from 2003, which likely resulted in improved overall survival over time. The majority of patients do not receive treatment though and prognosis is still poor.

Peritoneal disease: key imaging findings that help in the differential diagnosis

The peritoneum is a unique serosal membrane, which can be the site of primary tumors and, more commonly, secondary pathologic processes. Peritoneal carcinomatosis is the most common malignant condition to affect the peritoneal cavity, and the radiologist plays an important role in making the diagnosis and assessing the extent of disease, especially in sites that may hinder surgery. In this review, we address the role of the radiologist in the setting of peritoneal pathology, focusing on peritoneal carcinomatosis as this is the predominant malignant process, followed by revising typical imaging findings that can guide the differential diagnosis.We review the most frequent primary and secondary peritoneal tumor and tumor-like lesions, proposing a systemic approach based on clinical history and morphological appearance, namely distinguishing predominantly cystic from solid lesions, both solitary and multiple.

Novel Therapeutic Targets and Immune Dysfunction in Malignant Pleural Mesothelioma

Advances in the treatment of malignant pleural mesothelioma (MPM) have been disappointing, despite the apparent need for new therapeutic options for this rare and devastating cancer. Drug resistance is common and surgical intervention has brought benefits only to a subset of patients. MPM is a heterogenous disease with a surprisingly low mutation rate and recent sequencing efforts have confirmed alterations in a limited number of tumor suppressors that do not provide apparent insights into the molecular mechanisms that drive this malignancy. There is increasing evidence that epigenetic regulation leads to immune evasion and transformation in MPM. Further, the low efficacy of immune checkpoint inhibitors is consistent with a suppression of genes involved in the anti-tumor immune response. We review three promising emerging therapeutic targets (STAT3, KDM4A, heparanase) and highlight their potential effects on the immune response.

Malignant Peritoneal Mesothelioma Associated With Endometriosis: A Clinicopathologic Study of 15 Cases

Only a few cases of malignant peritoneal mesothelioma (MPeM) associated with endometriosis have been published; with chronic inflammation of the peritoneum associated with the latter being postulated as an inducing factor in the pathogenesis of this tumor. We assessed the clinicopathologic characteristics of MPeM associated with endometriosis to determine if there were other factors besides inflammation that may contribute to the pathogenesis in this patient population. Fifteen MPeM associated with endometriosis were retrieved from our files. Most presented with abdominal/pelvic pain, mass or distention; median age was 45 yr. Only 16% of patients had a history of asbestos exposure. In contrast, a third of the patients had a personal history of other neoplasms, and >80% had a family history of malignancies. Although most tumors had gross and microscopic features typical of MPeM, some had confounding features including "adhesion-like" appearance or gelatinous cysts/nodules, and signet ring cells. Tumors were epithelioid (9) and biphasic (6). MPeM was misdiagnosed as Müllerian carcinoma in 40% of cases. All patients (n=15) had cytoreductive surgery in addition to other therapies. Only 2/12 patients died of disease (17%). The 3- and 5-yr overall survival was 90%. MPeM associated with endometriosis tends to occur in patients with personal/familial history of malignancies, which may be a predisposing factor. In light of this finding, the role of endometriosis in the pathogenesis of MPeM is likely less relevant. The favorable outcome seen in these patients may be related to germline mutations or the hormonal milieu and needs further investigation.

Spindle Cell Tumors of the Pleura and the Peritoneum: Pathologic Diagnosis and Updates

A diverse group of both benign and malignant spindle cell tumors can involve the pleura or the peritoneum. Due to their rarity and overlapping morphologic features, these tumors can pose considerable diagnostic difficulty in surgical pathology. As these tumors differ in their prognosis and clinical management, their correct pathologic diagnosis is critical. In addition to histologic assessment, select immunohistochemical and molecular tools can aid the distinction among these tumors. In this review, we consider some of the major histologic differential diagnosis of spindle cell tumors involving these serosal membranes. This list of tumors includes: solitary fibrous tumor, inflammatory myofibroblastic tumor, desmoid fibromatosis, synovial sarcoma, sarcomatoid carcinoma, spindle cell melanoma, dedifferentiated liposarcoma, epithelioid hemangioendothelioma, and sarcomatoid mesothelioma. We describe their salient clinicopathologic and genetic findings, with a review on some of the recent discoveries on their molecular pathogenesis.

The Epithelial-to-Mesenchymal Transition (EMT) in the Development and Metastasis of Malignant Pleural Mesothelioma

Malignant pleural mesothelioma (MPM) is an aggressive tumor mainly associated with asbestos exposure and is characterized by a very difficult pharmacological approach. One of the molecular mechanisms associated with cancer onset and invasiveness is the epithelial-to-mesenchymal transition (EMT), an event induced by different types of inducers, such as transforming growth factor β (TGFβ), the main inducer of EMT, and oxidative stress. MPM development and metastasis have been correlated to EMT; On one hand, EMT mediates the effects exerted by asbestos fibers in the mesothelium, particularly via increased oxidative stress and TGFβ levels evoked by asbestos exposure, thus promoting a malignant phenotype, and on the other hand, MPM acquires invasiveness via the EMT event, as shown by an upregulation of mesenchymal markers or, although indirectly, some miRNAs or non-coding RNAs, all demonstrated to be involved in cancer onset and metastasis. This review aims to better describe how EMT is involved in driving the development and invasiveness of MPM, in an attempt to open new scenarios that are useful in the identification of predictive markers and to improve the pharmacological approach against this aggressive cancer.

Spontaneous Primary Pleural Mesothelioma in Fischer 344 (F344) and Other Rat Strains: A Retrospective Review

Spontaneous primary pleural mesotheliomas in Fischer 344 (F344) or other rat strains have rarely been reported. The objectives of this retrospective study were to develop historical incidence data and better characterize the light-microscopic morphology of these naturally occurring neoplasms in a large cohort of rats of several strains. A retrospective review was performed of National Toxicology Program (NTP) studies in rats conducted between 1980 and 2019 and comprising a total of 104,029 rats (51,326 males, 52,703 females), predominantly (90%) of the F344 strain. Of the 94,062 F344 rats surveyed, there were 30 cases of primary pleural mesotheliomas (22 males, 8 females). Of the 2998 Wistar Han rats surveyed, primary pleural mesotheliomas were present in 2 male rats. No primary pleural mesotheliomas were noted in male and female rats of other strains (6669 Sprague Dawley; 300 Osborne-Mendel). All primary pleural mesotheliomas in control and treated F344 and Wistar Han rats were considered spontaneous and unrelated to treatment. Based on light-microscopic evaluation of paraffin-embedded hematoxylin and eosin stained sections, only epithelioid and biphasic histologic subtypes were observed: 18 and 12 in F344 rats, respectively, and one each in Wistar Han rats. No sarcomatoid subtype cases were noted in any strain of rat.

A critical review of the 2020 EPA risk assessment for chrysotile and its many shortcomings

From 2018 to 2020, the United States Environmental Protection Agency (EPA) performed a risk evaluation of chrysotile asbestos to evaluate the hazards of asbestos-containing products (e.g. encapsulated products), including brakes and gaskets, allegedly currently sold in the United States. During the public review period, the EPA received more than 100 letters commenting on the proposed risk evaluation. The Science Advisory Committee on Chemicals (SACC), which peer reviewed the document, asked approximately 100 questions of the EPA that they expected to be addressed prior to publication of the final version of the risk assessment on 30 December 2020. After careful analysis, the authors of this manuscript found many significant scientific shortcomings in both the EPA's draft and final versions of the chrysotile risk evaluation. First, the EPA provided insufficient evidence regarding the current number of chrysotile-containing brakes and gaskets being sold in the United States, which influences the need for regulatory oversight. Second, the Agency did not give adequate consideration to the more than 200 air samples detailed in the published literature of auto mechanics who changed brakes in the 1970-1989 era. Third, the Agency did not consider more than 15 epidemiology studies indicating that exposures to encapsulated chrysotile asbestos in brakes and gaskets, which were generally in commerce from approximately 1950-1985, did not increase the incidence of any asbestos-related disease. Fourth, the concern about chrysotile asbestos being a mesothelioma hazard was based on populations in two facilities where mixed exposure to chrysotile and commercial amphibole asbestos (amosite and crocidolite) occurred. All 8 cases of pleural cancer and mesothelioma in the examined populations arose in facilities where amphiboles were present. It was therefore inappropriate to rely on these cohorts to predict the health risks of exposure to short fiber chrysotile, especially of those fibers filled with phenolic resins. Fifth, the suggested inhalation unit risk (IUR) for chrysotile asbestos was far too high since it was not markedly different than for amosite, despite the fact that the amphiboles are a far more potent carcinogen. Sixth, the approach to low dose modeling was not the most appropriate one in several respects, but, without question, it should have accounted for the background rate of mesothelioma in the general population. Just one month after this assessment was published, the National Academies of Science notified the EPA that the Agency's systematic review process was flawed. The result of the EPA's chrysotile asbestos risk evaluation is that society can expect dozens of years of scientifically unwarranted litigation. Due to an aging population and because some fraction of the population is naturally predisposed to mesothelioma given the presence of various genetic mutations in DNA repair mechanisms (e.g. BAP1 and others), the vast majority of mesotheliomas in the post-2035 era are expected to be spontaneous and unrelated in any way to exposure to asbestos. Due to the EPA's analysis, it is our belief that those who handled brakes and gaskets in the post-1985 era may now believe that those exposures were the cause of their mesothelioma, when a risk assessment based on the scientific weight of evidence would indicate otherwise.

War journalism: an occupational exposure

Apart from the risk of accidents, war theatres present a hazard related to numerous long-lasting toxic agents. For 10 years, a >60-year-old male journalist worked in war theatres in the Far and Near East where he was exposed to asbestos and other toxic substances (metals, silica, clays, polycyclic aromatic hydrocarbons and other organic substances) contained in dust and smoke of destroyed buildings. More than 15 years later, he developed a mucoepidermoid carcinoma of the soft palate and, subsequently, a pleural malignant mesothelioma. The safety of war journalists should focus not only on preventing the risk of being killed, but also on providing protection from toxic and carcinogenic agents. Exposure to substances released during the destruction of buildings can also pose a carcinogenic risk for survivors.

Current evidence and future perspectives of immune-checkpoint inhibitors in unresectable malignant pleural mesothelioma

Platinum-based chemotherapy is commonly used as the standard first-line treatment for unresectable malignant pleural mesothelioma (MPM). However, in recent times, immune-checkpoint inhibitors (ICIs) have led to a paradigm shift. Herein, we review relevant literature and ongoing trials of ICIs used as both first-line and salvage therapies. Specifically, in the Japanese single-arm, phase II trial, the MERIT trial, nivolumab, an antiprogrammed cell death 1 (PD-1) antibody showed favorable efficacy when used as a salvage therapy. Currently, multiple ICI monotherapy or combination therapy trials have been conducted, which could provide further evidence. Among available ICIs, the anti-PD-1 antibody is promising for unresectable MPM, despite the limited efficacy of anti-CTLA4 monotherapy. Ongoing studies will further confirm the potential efficacy of ICIs for MPM, as observed across other malignancies. It is also crucial to identify any clinically useful predictive biomarkers that could reveal ICIs with maximal effects in MPM.

An Unpleasant Surprise: Abdominal Presentation of Malignant Mesothelioma

Malignant mesothelioma is an aggressive cancer associated with asbestos exposure with median survival time of 8 to 14 months following diagnosis. Given that mesothelial cells also line the peritoneum and pericardium, malignant mesothelioma can present in unusual sites and in patients with nonrespiratory complaints. A 73-year-old male presented to the emergency department for worsening intermittent diffuse abdominal pain for the past 3 months with associated unintentional 40-pound weight loss, early satiety, and diarrhea. He denied exposure to asbestos. Computed tomography imaging revealed multiple masses concerning for malignancy including the primary retroperitoneal mass, a mass involving the terminal ileum, and a mass in the right upper lung. Esophagogastroduodenoscopy demonstrated significant mass effect within the stomach without signs of endoluminal infiltration. Computed tomography–guided biopsy of the retroperitoneal abdominal and intramuscular paraspinal masses was performed. Stage IV epithelioid mesothelioma was confirmed when hematoxylin and eosin staining revealed pleomorphic malignancy nuclei containing a vesicular chromatin pattern and prominent nucleoli and immunohistochemical staining was positive for CK Oscar, cytokeratin 7, GATA3, calretinin, EMA, and CK5/6. He was started on cisplatin, pemetrexed, and bevacizumab but developed severe abdominal pain with pneumoperitoneum and bowel perforation 1 month later and expired shortly thereafter. To our knowledge, this represents a highly atypical presentation of malignant mesothelioma considering the involvement of the retroperitoneum with diffuse lesions in the abdominopelvic cavity and thorax (sparing the lung pleurae). This case also calls attention to the occurrence of malignant mesothelioma in patients without known asbestos exposure and the crucial role of pathology in diagnosing atypical presentations.

Malignant mesothelioma: Ongoing controversies about its etiology in females

Malignant mesothelioma (MM) is one of the most aggressive cancers with the poorest of outcomes. There is no doubt that mesothelioma in males is related to asbestos exposure, but some authors suggest that most of the cases diagnosed in females are "idiopathic." In our assessment of the science, the "low risk" of mesothelioma in females is because of the nonsystematic recording of exposure histories among females. Indeed, asbestos exposure is mentioned in only some of the studies that include females. We estimate the risk of MM among females to be close to that in males. The absence of detailed exposure histories should be rectified in future studies involving ​women. As a matter of social justice, the ongoing failure to recognize asbestos as the cause of a majority of cases of MM in females does them, and their kin, a profound disservice.

Immune Microenvironment and Genetics in Malignant Pleural Mesothelioma

Malignant pleural mesothelioma (MPM) is a rare and aggressive malignancy with limited therapeutic options beyond surgery and cytotoxic chemotherapy. The success of immune checkpoint inhibition has been found to correlate with expression of immune-related genes such as CD274 (PD-L1) in lung and other solid cancers. However, only a small subset of MPM patients respond to checkpoint inhibition, and this response has been varied and unpredictable across several clinical trials. Recent advances in next-generation sequencing (NGS) technology have improved our understanding of the molecular features of MPM, also with respect to its genetic signature and how this impacts the immune microenvironment. This article will review current evidence surrounding the interplay between MPM genetics, including epigenetics and transcriptomics, and the immune response.

Potential airborne asbestos exposures in dentistry: a comprehensive review and risk assessment

Chrysotile was formerly used in the manufacture of casting ring liner (CRL) and periodontal dressing powder (PDP). The purpose of this study was to describe the potential for airborne asbestos exposure among dental professionals who may have used these products and to assess their risk of asbestos-related disease (ARD). Task-specific exposure data associated with CRL and PDP were identified and compared to regulatory standards for asbestos and health-based benchmarks. Personal airborne fiber concentrations ranged from 0.008-3.5 f/cc by PCM (duration: 3-420 minutes) for CRL (tearing, placement), and from <0.0044-<0.297 f/cc by PCM (duration: 5-28 minutes) for PDP (mixing). Eight-hour time-weighted average (TWA) exposures were calculated using the reported task-based airborne fiber concentrations and associated sampling durations. For CRL tasks, the upper-bound calculated 8-hour TWA of 0.022 f/cc (tearing, placement) did not exceed regulatory standards for asbestos (≥0.1 f/cc). All samples collected during the mixing of PDP resulted in non-measurable fiber concentrations. The greatest estimated cumulative asbestos exposure for dental professionals using CRL (tearing, placement) of 0.33 f/cc-years is well below "best estimate", published chrysotile no-observed-adverse-effect-levels (NOAEL) for ARD (lung cancer = 89-168 f/cc-years; pleural mesothelioma = 208-415 f/cc-years). As such, the use of asbestos-containing CRL and/or PDP is not expected to pose an increased risk of ARD among dental professionals. This conclusion is consistent with the lack of an increased risk of ARD reported in epidemiological studies of these occupations.

When the Diagnosis of Mesothelioma Challenges Textbooks and Guidelines

The diagnosis of malignant mesothelioma (MPM) does not pose difficulties when presenting with usual clinico-radiologic features and morphology. Pathology textbooks and national/international guidelines generally describe the findings of classic MPM, underlining common clinical presentation, the gold standard of sampling techniques, usual morphologic variants, immunohistochemical results of several positive and negative primary antibodies in the differential diagnosis, and the role of novel molecular markers. Nevertheless, MPM often does not follow the golden rules in routine practice, while the literature generally does not sufficiently emphasize unusual features of its manifestation. This gap may potentially create problems for patients in sustaining a difficult diagnosis of MPM in clinical practice and during legal disputes. Indeed, the guidelines accidentally tend to favor the job of lawyers and pathologists defending asbestos-producing industries against patients suffering from MPM characterized by uncommon features. The current review is aimed at underlining the wide spectrum of clinical and radiological presentation of MPM, the possibility to consistently use cytology for diagnostic intent, the aberrant immunohistochemical expression using so-called specific negative and positive primary antibodies, and finally proposing some alternative and more unbiased approaches to the diagnosis of MPM.

Pediatric Mesothelioma With ALK Fusions: A Molecular and Pathologic Study of 5 Cases

Pediatric mesotheliomas are rare and their pathogenesis remains undefined. In this study, we report 5 cases of malignant mesothelioma in children, characterized by fusions involving the anaplastic lymphoma kinase (ALK) gene. Four cases occurred in females involving the abdominal cavity and were characterized by a pure epithelioid morphology. The fifth arose in the tunica vaginalis of a 15-year-old male and displayed a biphasic epithelioid-sarcomatoid phenotype. All cases demonstrated the classic morphologic and immunohistochemical features of malignant mesothelioma, including tubulopapillary architecture and cuboidal epithelioid cells with eosinophilic cytoplasm and uniform nuclei with vesicular chromatin. Immunohistochemically, all cases showed labeling for ALK, cytokeratins, WT1, and calretinin, while lacking expression of adenocarcinoma immunomarkers. Four cases demonstrated weak-moderate labeling for PAX8 protein, which resulted in diagnostic challenges with primary peritoneal serous carcinoma. The ALK genetic abnormalities were investigated by a combination of molecular methods. Archer FusionPlex was performed in 2 cases, showing fusions between ALK with either STRN or TPM1 genes, resulting in a transcript that retained the ALK kinase domain. One case was further studied by DNA targeted sequencing, but no additional genetic alterations were observed. In 1 case, cytogenetic analysis showed the presence of a t(2;15)(p23;q22) and fluorescence in situ hybridization confirmed the ALK gene break-apart. In the remaining 2 cases, ALK gene rearrangements were demonstrated by fluorescence in situ hybridization. Unlike adult mesotheliomas, which are tightly linked to asbestos exposure, often show loss of BAP1 expression and have complex karyotypes, ALK-rearranged mesothelioma appears to be similar to other fusion-positive mesotheliomas, such as those harboring EWSR1/FUS-ATF1 fusions, sharing significant morphologic overlap, occurring in young patients and displaying a simple, translocation-driven genetic profile.

Tongue: the unusual site in malignant pleural mesothelioma

Malignant mesotheliomas (MMs) are malignancies of the mesothelium, with primary deposits originating in the pleura, peritoneum, pericardium and the tunica vaginalis (ie, testicular). Metastatic spread is commonly reported to affect the liver, adrenal glands, kidney and contralateral lung (in cases of malignant pleural mesothelioma). Metastases to distant sites are uncommon. Spread to the oral cavity in particular is very rare. A total of 23 cases of metastatic spread to the oral cavity have been reported in the literature to date; of those, 9 cases have been to the tongue. Given the rarity of the site of metastasis, the management remains challenging. This case highlights a rare site of metastasis in MM, discusses treatment options available and briefly talks about technical limitations in treating a mobile structure such as the tongue. Good palliative and supportive care is crucial in managing cases where no curative treatment is possible.

Ongoing downplaying of the carcinogenicity of chrysotile asbestos by vested interests

Industries that mine, manufacture and sell asbestos or asbestos-containing products have a long tradition of promoting the use of asbestos, while placing the burden of economic and health costs on workers and society. This has been successfully done in recent years and decades in spite of the overwhelming evidence that all asbestos types are carcinogenic and cause asbestosis. In doing so, the asbestos industry has undermined the WHO campaign to reach a worldwide ban of asbestos and to eliminate asbestos-related diseases. Even worse, in recent years they succeeded in continuing asbestos mining and consuming in the range of about 1.3 million tons annually. Nowadays, production takes place predominantly in Russia, Kazakhstan and China. Chrysotile is the only asbestos type still sold and represents 95% of asbestos traded over the last century.The asbestos industry, especially its PR agency, the International Chrysotile Association, ICA, financed by asbestos mining companies in Russia, Kazakhstan and Zimbabwe and asbestos industrialists in India and Mexico, continues to be extremely active by using slogans such as chrysotile can be used safely.Another approach of the asbestos industry and of some of its insurance agencies is to broadly defeat liability claims of asbestos victims.In doing so they systematically use inappropriate science produced by their own and/or by industry-affiliated researchers. Some of the latter were also engaged in producing defense material for other industries including the tobacco industry. Frequent examples of distributing such disinformation include questioning or denying established scientific knowledge about adverse health effects of asbestos. False evidence continues to be published in scientific journals and books.The persisting strong influence of vested asbestos-related interests in workers and public health issues including regulations and compensation necessitate ongoing alertness, corrections and appropriate reactions in scientific as well as public media and policy advisory bodies.

Malignant Peritoneal Mesothelioma Arising in Young Adults With Long-standing Indwelling Intra-abdominal Shunt Catheters

Only 50% to 70% of patients with mesothelioma report asbestos exposure. Other exposures (eg, radiation) play a role in some cases, but some patients have no obvious cause. We describe a series of patients with long-standing indwelling intra-abdominal shunt catheters who developed malignant peritoneal mesothelioma, suggesting a novel association. We identified 7 patients who had shunts and subsequently developed mesothelioma (5 women; median age: 31 y, range: 18 to 45 y). Clinical history and pathology materials were reviewed, and RNA sequencing was performed. Clinical presentations varied; 6 patients had hydrocephalus and a ventriculoperitoneal shunt, and 1 patient had portal hypertension and a portoatrial shunt. The median duration of shunt therapy in 5 cases was 29 years (range: 12 to 35 y); the remaining 2 patients also had shunts for many years, but specific details were unavailable. Two patients had radiotherapy for malignancies in childhood. One had an alleged exposure to asbestos and 1 had prior exposure to talc. The rest had no known risk factors. Histologically, all tumors were purely epithelioid. Treatments included surgical debulking, chemotherapy, and palliative care. All 7 died of disease (median survival: 7 mo, range: 1 to 18 mo). Molecular testing showed loss of NF2 and CDKN2A/B and a BAP1 mutation in 1 case, and no genomic alterations associated with mesothelioma in 2 cases. Peritoneal mesothelioma may represent a complication of long-standing indwelling shunt catheters. The mechanism is unknown, but chronic peritoneal irritation may play a role. Albeit rare, mesothelioma should be considered in patients with a shunt who present with new ascites.

A quantitative weight of evidence assessment of Hill's guidelines for causal inference for cosmetic talc as a cause of mesothelioma

Cosmetic talc has been suggested to cause mesothelioma. To assess a potential causal relationship between cosmetic talc and mesothelioma, a quantitative weight of evidence analysis was performed in accordance with Hill's nine original guidelines for causal inference using a published empirical model to weight each respective guideline. Various epidemiological, toxicological, and exposure studies related to cosmetic talc and risk of mesothelioma were included in an evaluation of each of Hill's guidelines. Probabilities that the guidelines were true were assigned based on expert judgment. We applied a sensitivity analysis to evaluate the variability of our probability estimates. The overall probability of causality for cosmetic talc and mesothelioma was approximately 1.29% (range: 0.73%-3.96%). This low probability of causality supports the conclusion that cosmetic talc is not related to the development of mesothelioma.

Pathology of Malignant Pleural Mesothelioma

Despite multiple diagnostic toolkits, the diagnosis of diffuse malignant pleural mesothelioma relies primarily on proper histologic assessment. The definitive diagnosis of diffuse malignant pleural mesothelioma is based on the pathologic assessment of tumor tissue, which can be obtained from core biopsy sampling, pleurectomy, or other more extensive resections, such as extrapleural pneumonectomy. Given its rarity and overlapping microscopic features with other conditions, the histologic diagnosis of diffuse malignant pleural mesothelioma is challenging. This review discusses the pathologic features and the differential diagnosis of diffuse malignant pleural mesothelioma, including select diagnostic pitfalls.

Malignant Mesothelioma of the Peritoneum in Women: A Clinicopathologic Study of 164 Cases

Malignant mesothelioma of the peritoneum in women is an uncommon tumor. In this study, we present the clinicopathologic features of 164 such cases seen in our institution over a period of 42 years (1974-2016). Clinical information, pathologic findings, immunohistochemical results, and follow-up were recorded. Hematoxylin and eosin-stained slides were reviewed in all cases. Patients ranged in age from 3 to 85 years, median: 49 years. Most patients presented with abdominal/pelvic pain, although some were asymptomatic, presented with paraneoplastic syndromes or cervical lymphadenopathy. Overall, 9% of patients had a history of direct or indirect exposure to asbestos. In total, 31% and 69% of patients had either a personal or family history of other tumors; most of these tumors are currently recognized as part of a syndrome. Genetic testing information was available in 5 patients: BAP-1 germline mutation (1), type 2 neurofibromatosis (1), Lynch syndrome (1), McCune-Albright syndrome (1), no BAP-1 or TP53 mutation (1). Most cases had gross and microscopic features typical of malignant mesothelioma of the peritoneum in women; however, some had confounding features such as gelatinous appearance, signet ring or clear cells, and well-differentiated papillary mesothelioma-like areas. Calretinin and WT-1 were the markers more frequently expressed, and up to 23% of the cases showed PAX-8 expression. Patients' treatments predominantly included: chemotherapy, cytoreductive surgery, and hyperthermic intraperitoneal chemotherapy. On multivariate analysis, the predominance of deciduoid cells, nuclear grade 3, and the absence of surgical treatment were associated with worse overall survival (OS). For all patients, the 3- and 5-year OS were 74.3% and 57.4%, respectively. The 3- and 5-year OS for patients treated with cytoreductive surgery, and hyperthermic intraperitoneal chemotherapy were 88.9% and 77.8%, respectively.

The role of BCL-2 family proteins and therapeutic potential of BH3-mimetics in malignant pleural mesothelioma

Introduction: With limited recent therapeutic changes, malignant pleural mesothelioma (MPM) is associated with poor survival and death within 12 months, making it one of the most lethal malignancies. Due to unregulated asbestos use in developing countries and home renovation exposures, cases of MPM are likely to present for decades. As MPM is largely driven by dysregulation of tumor suppressor genes, researchers have examined other mechanisms of subverting tumor proliferation and spread. Over-expression of pro-survival BCL-2 family proteins impairs cells from undergoing apoptosis, and BH3-mimetics  targeting them are a novel treatment option across various cancers, though have not been widely investigated in MPM.Areas covered: This review provides an overview of MPM and its current treatment landscape. It summarizes the role of BCL-2 family proteins in tumorigenesis and the therapeutic potential of BH3-mimetics . Finally, it discusses the role of BCL-2 proteins in MPM and the pre-clinical rationale for investigating BH3-mimetics as a therapeutic strategy.Expert opinion: As a disease without readily actionable oncogene driver mutations and with modest benefit from immune checkpoint inhibition, novel therapeutic options are urgently needed for MPM. Hence, BH3-mimetics provide a promising treatment option, with evidence supporting dependence on pro-survival BCL-2 proteins for MPM cell survival.

Occurrence of asbestos-related occupational diseases in the Czech Republic in the last 20 years

OBJECTIVES

Asbestos-related diseases are still a current problem worldwide. What is their occurrence in the Czech Republic? The answer is the subject of this study, which aims to provide a general and regional overview of the situation over the last 20 years with a more detailed focus on mesothelioma, the development of which is highly associated with asbestos exposure and the issue of their recognition as an occupational disease.

METHODS

In its retrospective reviews, the study is based on analyses of data from the Institute of Health Information and Statistics of the Czech Republic and data from the Czech National Cancer Registry, which also interconnects.

RESULTS

In the last 20 years, 512 new cases of occupational diseases from asbestos have been reported, namely 228 cases of pleural thickening, 133 mesotheliomas, 92 asbestoses, and 59 cases of lung cancer. In the last 5 years, mesotheliomas (n = 39) predominated among the reported diseases with a 45% proportion in the total number of 86 cases. The trend in their incidence, as the only one among asbestos-related diseases, is not declining. There was a significant difference in the overall incidence of mesothelioma in a general population and the incidence of occupational mesotheliomas. At the national level, occupational aetiology was acknowledged in only 11.3% of cases of mesothelioma on average. The highest proportion of occupational mesotheliomas and the highest incidence of all asbestos-related diseases were found in regions where the largest asbestos processing plants were located.

CONCLUSION

The authors emphasize the importance of work history for the diagnostic process of asbestos-related diseases and also the need to perform follow-up examinations for their early detection.

Molecular characterization of diffuse malignant peritoneal mesothelioma

Malignant peritoneal mesothelioma is a rare aggressive tumor that arises from the peritoneal lining. While recurrent BAP1 mutations have been identified in a subset of mesotheliomas, molecular characteristics of peritoneal mesotheliomas, including those lacking BAP1 alterations, remain poorly understood. Using targeted next-generation sequencing, we examined the molecular features of 26 diffuse malignant peritoneal mesotheliomas. As part of an exploratory analysis, we analyzed an additional localized peritoneal mesothelioma and one well-differentiated papillary mesothelioma with invasive foci. Genomic characterization identified categories of diffuse malignant peritoneal mesotheliomas: The first group included 18 (69%) tumors with recurrent BAP1 alterations, with eight (31%) having more than one BAP1 alterations, and concomitant alterations in PBRM1 (46%) and SETD2 (35%). All tumors with complete loss of BAP1 expression by immunohistochemistry harbored BAP1 molecular alterations. PBRM1 alterations were significantly enriched in the BAP1-altered cohort. Frequent copy number loss of BAP1, ARID1B, PRDM1, PBRM1, SETD2, NF2, and CDKN2A was noted. The second group included eight (31%) BAP1-wild-type tumors: two with TP53 mutations, one with a TRAF7 activating mutation, one with a SUZ12 inactivating mutation, and three with ALK rearrangements that we previously published. One TP53-mutant biphasic mesothelioma showed evidence of genomic near-haploidization showing loss of heterozygosity of all chromosomes except 5, 7, 16, and 20. The localized peritoneal mesothelioma harbored a nonsense CHEK2 mutation, and the well-differentiated papillary mesothelioma with invasive foci harbored no reportable variants. In conclusion, we described the genetic categories of diffuse malignant peritoneal mesotheliomas, with BAP1-mutant and BAP1-wild-type groups. Our findings implicated DNA repair, epigenetics, and cell cycle regulation in the pathogenesis of peritoneal mesotheliomas, with identification of potential therapeutic targets.

Association between asbestos exposure and pericardial and tunica vaginalis testis malignant mesothelioma: a case-control study and epidemiological remarks

Objectives The purposes of this study are to describe the epidemiology of pericardial and tunica vaginalis testis mesothelioma and assess the role of asbestos exposure for these rare diseases. Methods Based on incident pericardial and tunica vaginalis testis mesothelioma cases collected from the Italian national mesothelioma registry (ReNaM) in the period 1993-2015, incidence rates, survival median period and prognostic factors have been evaluated. A case-control study has been performed to analyze the association with asbestos exposure (occupational and non-occupational) for these diseases. Results Between 1993 and 2015, 58 pericardial (20 women and 38 men) and 80 tunica vaginalis testis mesothelioma cases have been registered with a mean annual standardized (world standard population as reference) incidence rates of 0.049 (per million) in men and 0.023 in women for the pericardial site, and 0.095 for tunica vaginalis testis mesothelioma. Occupational exposure to asbestos was significantly associated with the risk of the diseases [odds ratio (OR) 3.68, 95% confidence interval (CI) 1.85-7.31 and OR 3.42, 95% CI 1.93-6.04 in pericardial and tunica vaginalis testis mesothelioma, respectively]. The median survival was 2.5 months for pericardial and 33.0 months for tunica vaginalis testis mesotheliomas. Age was the main predictive factor for survival for both anatomical sites. Conclusions For the first time in an analytical study, asbestos exposure was associated with pericardial and tunica vaginalis testis mesothelioma risk, supporting the causal role of asbestos for all anatomical sites. The extreme rarity of the diseases, the poor survival and the prognostic role of age have been confirmed based on population and nationwide mesothelioma registry data.

Mesothelioma Biomarkers: Discovery in Search of Validation

Malignant pleural mesothelioma (MPM) is an asbestos-related neoplasm that can only be treated successfully when correctly diagnosed and treated early. The asbestos-exposed population is a high-risk group that could benefit from sensitive and specific blood- or tissue-based biomarkers. We review recent work with biomarker development in MPM and literature of the last 20 years on the most promising blood- and tissue-based biomarkers. Proteomic, genomic, and epigenomic platforms are covered. SMRP is the only validated blood-based biomarker with diagnostic, monitoring and prognostic value. To strengthen development and testing of MPM biomarkers, cohorts for validation must be established by enlisting worldwide collaborations.

The Molecular Basis of Malignant Pleural Mesothelioma

Malignant pleural mesothelioma (MPM) is a rare, aggressive malignancy of the pleural lining associated with asbestos exposure in greater than 80% of cases. It is characterized by molecular heterogeneity both between patients and within individual tumors. Next-generation sequencing technology and novel computational techniques have resulted in a greater understanding of the epigenetic, genetic, and transcriptomic hallmarks of MPM. This article reviews these features and discusses the implications of advances in MPM molecular biology in clinical practice.

Geographic study of mortality due to mesothelioma in Peru and its evolution

BACKGROUND

Peru has a public health problem because of asbestos imports. We analyzed the mortality trends for mesothelioma in Peru and its provinces from 2005 to 2014 and estimated their relationship with the amount of asbestos imported previously.

METHODS

We computed age-standardized mortality rates (ASMRs) per 100,000 population (direct method and SEGI world standard population reference), and the standardized mortality ratio (SMR). The relationship between the amount of asbestos imported annually along the period 1965-2010 and the number of mesothelioma deaths per year from 2005 to 2014 was estimated by log-linear Poisson regression models and Pearson correlation calculations.

RESULTS

After correcting the number of deaths, Peru registered 428 cases (or 430 when corrected cases are rounded by sex) between 2005 and 2014. The highest ASMRs were in Arequipa and Callao (range: 0.40-0.41/100,000 population), followed by Huancavelica (0.36/100,000 population). This translates into approximately one death per each 68-111 of asbestos tons imported. The latency period for the higher level of positive correlation found was 8 years (r = 0.8). Male female sex ratio was lower in provinces such as Junin and Hunacavelica with geological asbestos risk.

CONCLUSIONS

Two patterns of mesothelioma risk have been detected, occupational and environmental. During the 2002-2006 years, Peru increased the asbestos use. If crocidolite imports were also increased, this could be behind the 8 years latency period detected. Peru should boost strategies towards the total ban of all forms of asbestos.

Reactive mesothelial hyperplasia mimicking mesothelioma in an African green monkey (Chlorocebus aethiops)

A spontaneous reactive mesothelial hyperplasia occurred in a female, 15.7-year-old African green monkey (grivet; Chlorocebus aethiops). At necropsy, massive effusions were found in the abdomen, the thorax, and the pericardium. Additionally, multiple small, beige-gray nodules were detected on the serosal surfaces of the abdominal organs. Histopathologically, the mesothelial cells resembled the epithelioid subtype of a mesothelioma, but no infiltrative or invasive growth could be demonstrated. The mesothelial cells on the thoracis, liver, and intestinal serosa were accompanied by chronic serositis. Mesothelial cells expressed cytokeratin, vimentin, calretinin, desmin, Wilms Tumor 1 (WT-1) protein, and epithelial membrane antigen (EMA). Cells were negative for carcinoembryonic antigen (CEA), cluster of differentiation 15 (CD15), and podoplanin. Ultrastructurally, cells revealed a moderate amount of microvilli of medium length, perinuclear tonofilament bundles, and long desmosomes. In fluorescence in situ hybridization (FISH) for the detection of characteristic gene loss (p16; CDKN2A), NF2, and MTAP, no deletions were detected. No asbestos fibers and no presence of Simian virus 40 antigen (SV40) could be demonstrated.

Malignant Diffuse Mesothelioma in Women: A Study of 354 Cases

We reviewed 354 cases of malignant diffuse mesothelioma (MM) in women from a database of 2858 histologically confirmed MM cases. There was a pleural predominance with 78% pleural MM and 22% peritoneal MM. The pleural tumors consisted of 72% epithelioid, 19% biphasic, and 9% sarcomatoid variant. The peritoneal tumors consisted of 82% epithelioid, 13% biphasic, and 5% sarcomatoid. The immunohistochemical profile was typical of what is well-accepted and previously described for MM. When examining tumor subtype and location, there was a trend toward epithelioid subtype and peritoneal location; however, this did not reach statistical significance. Age at the time of diagnosis ranged from 19 to 93 years with a mean of 60 years. The median age at time of diagnosis for pleural MM was 65 years and for peritoneal MM was 52 years. A further look at age and histologic subtype showed no statistically significant difference in age between MM subtypes. Survival was greatest for epithelioid variant, and this was magnified in the peritoneum. A majority of our cases were exposed to asbestos through a household contact. Asbestosis and parietal pleural plaque were present in 5% and 50% of cases with data, respectively. Fiber analysis data was available in 67 cases; 38 cases had elevated asbestos fiber burden, and tremolite was the most common asbestos fiber type detected. Commercial and noncommercial amphibole asbestos fibers were elevated in nearly equal numbers of cases.

Mesothelioma Biomarkers: A Review Highlighting Contributions from the Early Detection Research Network

Malignant pleural mesothelioma (MPM) is an asbestos-related neoplasm, which can be treated successfully only if correctly diagnosed and treated in early stages. The asbestos-exposed population serves as a high-risk group that could benefit from sensitive and specific blood- or tissue-based biomarkers. This review details the recent work with biomarker development in MPM and the contributions of the NCI Early Detection Research Network Biomarker Developmental Laboratory of NYU Langone Medical Center. The literature of the last 20 years was reviewed to comment on the most promising of the blood- and tissue-based biomarkers. Proteomic, genomic, and epigenomic platforms as well as novel studies such as "breath testing" are covered. Soluble mesothelin-related proteins (SMRP) have been characterized extensively and constitute an FDA-approved biomarker in plasma with diagnostic, monitoring, and prognostic value in MPM. Osteopontin is found to be a valuable prognostic biomarker for MPM, while its utility in diagnosis is slightly lower. Other biomarkers, such as calretinin, fibulin 3, and High-Mobility Group Box 1 (HMGB1), remain under study and need international validation trials with large cohorts of cases and controls to demonstrate any utility. The EDRN has played a key role in the development and testing of MPM biomarkers by enlisting collaborations all over the world. A comprehensive understanding of previously investigated biomarkers and their utility in screening and early diagnosis of MPM will provide guidance for further future research.See all articles in this CEBP Focus section, "NCI Early Detection Research Network: Making Cancer Detection Possible."

Malignant Pleural Mesothelioma: Genetic and Microenviromental Heterogeneity as an Unexpected Reading Frame and Therapeutic Challenge

Mesothelioma is a malignancy of serosal membranes including the peritoneum, pleura, pericardium and the tunica vaginalis of the testes. Malignant mesothelioma (MM) is a rare disease with a global incidence in countries like Italy of about 1.15 per 100,000 inhabitants. Malignant Pleural Mesothelioma (MPM) is the most common form of mesothelioma, accounting for approximately 80% of disease. Although rare in the global population, mesothelioma is linked to industrial pollutants and mineral fiber exposure, with approximately 80% of cases linked to asbestos. Due to the persistent asbestos exposure in many countries, a worldwide progressive increase in MPM incidence is expected for the current and coming years. The tumor grows in a loco-regional pattern, spreading from the parietal to the visceral pleura and invading the surrounding structures that induce the clinical picture of pleural effusion, pain and dyspnea. Distant spreading and metastasis are rarely observed, and most patients die from the burden of the primary tumor. Currently, there are no effective treatments for MPM, and the prognosis is invariably poor. Some studies average the prognosis to be roughly one-year after diagnosis. The uniquely poor mutational landscape which characterizes MPM appears to derive from a selective pressure operated by the environment; thus, inflammation and immune response emerge as key players in driving MPM progression and represent promising therapeutic targets. Here we recapitulate current knowledge on MPM with focus on the emerging network between genetic asset and inflammatory microenvironment which characterize the disease as amenable target for novel therapeutic approaches.