Mesothelioma epidemiology, carcinogenesis, and pathogenesis

Cisplatin plus pemetrexed therapy and subsequent immune checkpoint inhibitor administration for malignant peritoneal mesothelioma without pleural lesions: Case report

RATIONALE

Malignant peritoneal mesothelioma is a rare tumor with a poor prognosis and has no recommended therapy after first-line pemetrexed and platinum-based chemotherapy. Moreover, effects of immune checkpoint inhibitors on peritoneal mesothelioma remains to be elucidated. We herein report the case of a 75-year-old man with peritoneal mesothelioma treated with cisplatin plus pemetrexed and subsequent nivolumab.

PATIENT CONCERNS

A 75-year-old man was referred to our hospital due to lower abdominal pain.

DIAGNOSIS

Positron emission tomography-computed tomography (CT) showed the accumulation of fluorodeoxyglucose in an intraperitoneal mass. A histological examination of a laparoscopic biopsy specimen revealed malignant peritoneal mesothelioma.

INTERVENTIONS

After 4 cycles of cisplatin plus pemetrexed and 13 subsequent cycles of pemetrexed maintenance therapy showed beneficial responses until CT revealed liver metastasis. Nivolumab was then administered as the second-line therapy.

OUTCOMES

After 3 cycles of biweekly nivolumab administration, he developed severe abdominal distention. CT revealed an intraperitoneal mass growing much more rapidly than ever, indicating hyperprogressive disease after nivolumab treatment. He ultimately died 51 days after the initial nivolumab administration.

LESSONS

To our knowledge, this is the first report of hyperprogressive disease in a case of peritoneal mesothelioma after nivolumab treatment. While immune checkpoint inhibitors may be promising therapeutic strategies for treating malignant peritoneal mesothelioma, careful monitoring must be practiced with their application.

MiR-144: A New Possible Therapeutic Target and Diagnostic/Prognostic Tool in Cancers

MicroRNAs (miRNAs) are small and non-coding RNAs that display aberrant expression in the tissue and plasma of cancer patients when tested in comparison to healthy individuals. In past decades, research data proposed that miRNAs could be diagnostic and prognostic biomarkers in cancer patients. It has been confirmed that miRNAs can act either as oncogenes by silencing tumor inhibitors or as tumor suppressors by targeting oncoproteins. MiR-144s are located in the chromosomal region 17q11.2, which is subject to significant damage in many types of cancers. In this review, we assess the involvement of miR-144s in several cancer types by illustrating the possible target genes that are related to each cancer, and we also briefly describe the clinical applications of miR-144s as a diagnostic and prognostic tool in cancers.

Prognostic factors of survival in patients with malignant pleural mesothelioma: an analysis of the National Cancer Database

Malignant pleural mesothelioma (MPM) is a rare disease with a very poor prognosis. Previous studies have indicated that women experience longer survival compared with men. We analyzed 16 267 eligible patients (21.3% females) in the National Cancer Database to evaluate which clinical factors are independently predictive of longer survival. After adjusting for all covariates, survival was significantly better in females compared with males [HRadj: 0.81, 95% confidence interval (CI): 0.77-0.85]. Other factors significantly associated with better survival were younger age at diagnosis, higher income, lower comorbidity score, epithelial histology, earlier stage and receipt of surgical or medical treatment. After propensity matching, survival was significantly better for females compared with males [hazard ratio (HR): 0.86, 95% CI: 0.80-0.94]. After propensity matching within the epithelial group, survival remained significantly better for females compared with males (HR: 0.85, 95% CI: 0.74-0.97). This study adds information to the known significant gender survival difference in MPM by disentangling the effect of gender from the effect of age and histology, two known independent factors affecting survival. Circulating estrogen, present in young but not older women, and higher expression of the estrogen receptor beta in epithelial mesothelioma have been suggested to play a role in gender survival differences. These findings may lead to exploring new therapeutic options, such as targeting estrogen receptor beta, and considering hormonal therapy including estrogens for patients with otherwise limited prognosis.

An overview of existing mesothelioma registries worldwide, and the need for a US Registry

The association between asbestos exposure, mainly in occupational settings, and malignant mesothelioma has been well established; this has prompted several countries to establish mesothelioma epidemiologic surveillance programs often at the request of national agencies. This review compares currently existing mesothelioma registries worldwide to develop a concept model for a US real-time case capture mesothelioma registry. Five countries were identified with a mesothelioma specific registry, including Italy, France, UK, Australia, and South Korea. All, except the UK, used interviews to collect exposure data. Linkage with the national death index was available or was in future plans for all registries. The registries have limited information on treatment, quality of life, and other patient-centered outcomes such as symptoms and pain management. To thoroughly collect exposure data, "real-time" enrollment is preferable; to maximize the capture of mesothelioma cases, optimal coverage, and a simplified consent process are needed.

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.

Peritoneal mesothelioma

Malignant peritoneal mesothelioma (MPM) is a rare and lethal disease of the peritoneal lining, with high variability in biologic aggressiveness. Morbidity and mortality of the disease are related to progressive locoregional effects within the abdominal cavity, such as distention, pain, early satiety, and decreased oral intake that can ultimately lead to bowel obstruction and cachexia. The standard of care for patients with resectable disease remains cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS-HIPEC), with potential survival outcomes greater than 5 years in appropriately selected patients. Patients with inoperable MPM can be offered systemic treatment, although the disease is usually refractory to standard chemotherapic regimens. Patients with MPM should be treated at high volume centers with strong consideration for inclusion in tumor registries and clinical trials. In 2020, research will continue to explore promising genetic and immunologic targets and focus on refinement of surgical methods to optimize CRS-HIPEC approaches.

SV40 and human mesothelioma

Simian virus 40 (SV40) is a DNA tumor virus capable of infecting and transforming human mesothelial (HM) cells in vitro. Hamsters injected intracardially to expose most tissue types to SV40 preferentially develop mesotheliomas. In humans, asbestos is the main cause of mesothelioma, and asbestos and SV40 are co-carcinogens in transforming HM cells in tissue culture and in causing mesothelioma in hamsters. Laser microdissection experiments conducted in the laboratory of Adi Gazdar demonstrated that SV40 was present specifically in the malignant mesothelioma cells and not in nearby stromal cells. Further experiments demonstrated that SV40 remains episomal in HM cells and astrocytes because of the production of a long antisense RNA that represses viral capsid protein production. Thus, the potent SV40 oncoprotein, T-antigen (Tag), is expressed, but because the capsid proteins are not produced, the cells are not lysed and, instead, become transformed. Together this evidence suggests that SV40 may contribute to the development of mesotheliomas in humans. However, epidemiological evidence to support this hypothesis is lacking. This chapter also summarizes the introduction of SV40, a monkey virus, into the human population as an unrecognized contaminant of early poliovaccines. In addition to mesotheliomas, SV40 now is linked with brain cancers, osteosarcomas, and lymphomas in humans. Explanations are provided for the apparent geographic variations in SV40 prevalence and for controversies about the role of SV40 in human cancer.

North-south gradient of mesothelioma and asbestos consumption-production in the United States-Progresses since the 1st asbestos partial ban in 1973

BACKGROUND

Temporal trends and broad geographical distributions of asbestos use and the incidence of malignant mesothelioma (MM) in the US still need to be studied.

METHODS

Data on asbestos consumption and production between 1900 and 2015 and MM mortality and incidence rates between 1975 and 2015 in the US were examined. Spatial distributions of MM mortality and incidence rates and their association with climate zone were analyzed.

RESULTS

Decline of MM incidence and mortality rates in the US occurred about 20 years after the peak of asbestos consumption-production in 1973. There are apparent north-south (N-S) gradients in MM mortality and incidence rates in the US.

CONCLUSION

Recent decline of MM incidence and mortality rates in the US may be associated with reduced US asbestos consumption. N-S MM gradients between 1999 and 2015 were likely related to larger asbestos requirements in building materials in the northern states.

Mechanisms and Functions of Chemerin in Cancer: Potential Roles in Therapeutic Intervention

Chemerin [RARRES2 [retinoic acid receptor responder 2], TIG2 [tazarotene induced gene 2 (TIG2)]] is a multifunctional cytokine initially described in skin cultures upon exposure to the synthetic retinoid tazarotene. Its secreted pro-form, prochemerin, is widely expressed, found systemically, and is readily converted into active chemerin by various proteases. Subsequent studies elucidated major roles of chemerin as both a leukocyte chemoattractant as well as an adipokine. Chemerin's main chemotactic receptor, the G-protein coupled receptor CMKLR1, is expressed on macrophages, dendritic, and NK cells. With respect to its role in immunology, chemerin mediates trafficking of these cells to sites of inflammation along its concentration gradient, and likely helps coordinate early responses, as it has been shown to have antimicrobial and angiogenic properties, as well. Recently, there has been mounting evidence that chemerin is an important factor in various cancers. As with its role in immune responses-where it can act as both a pro- and anti-inflammatory mediator-the potential functions or correlations chemerin has in or with cancer appears to be context dependent. Most studies, however, suggest a downregulation or loss of chemerin/RARRES2 in malignancies compared to the normal tissue counterparts. Here, we perform a comprehensive review of the literature to date and summarize relevant findings in order to better define the roles of chemerin in the setting of the tumor microenvironment and tumor immune responses, with an ultimate focus on the potential for therapeutic intervention.

Biodistribution and Tumor Uptake of 67Ga-Nimotuzumab in a Malignant Pleural Mesothelioma Xenograft

Malignant pleural mesothelioma (MPM) is the most common tumor of the pulmonary pleura. It is a rare and aggressive malignancy, generally associated with continuous occupational exposure to asbestos. Only a multimodal-approach to treatment, based on surgical resection, chemotherapy and/or radiation, has shown some benefits. However, the survival rate remains low. Nimotuzumab (h-R3), an anti-EGFR (epidermal growth factor receptor) humanized antibody, is proposed as a promising agent for the treatment of MPM. The aim of this research was to implement a procedure for nimotuzumab radiolabeling to evaluate its biodistribution and affinity for EGF (epidermal growth factor) receptors present in a mesothelioma xenograft. Nimotuzumab was radiolabeled with 67Ga; radiolabel efficiency, radiochemical purity, serum stability, and biodistribution were evaluated. Biodistribution and tumor uptake imaging studies by microSPECT/CT in mesothelioma xenografts revealed constant nimotuzumab uptake at the tumor site during the first 48 h after drug administration. In vivo studies using MPM xenografts showed a significant uptake of this radioimmunoconjugate, which illustrates its potential as a biomarker that could promote its theranostic use in patients with MPM.

Preclinical investigation of folate receptor-targeted nanoparticles for photodynamic therapy of malignant pleural mesothelioma

Photodynamic therapy (PDT) following lung-sparing extended pleurectomy for malignant pleural mesothelioma (MPM) has been investigated as a potential means to kill residual microscopic cells. High expression levels of folate receptor 1 (FOLR1) have been reported in MPM; therefore, targeting FOLR1 has been considered a novel potential strategy. The present study developed FOLR1‑targeting porphyrin-lipid nanoparticles (folate-porphysomes, FP) for the treatment of PDT. Furthermore, inhibition of activated epidermal growth factor (EGFR)-associated survival pathways enhance PDT efficacy. In the present study, these approaches were combined; FP-based PDT was used together with an EGFR-tyrosine kinase inhibitor (EGFR-TKI). The frequency of FOLR1 and EGFR expression in MPM was analyzed using tissue microarrays. Confocal microscopy and a cell viability assay were performed to confirm the specificity of FOLR1‑targeting cellular uptake and photocytotoxicity in vitro. In vivo fluorescence activation and therapeutic efficacy were subsequently examined. The effects of EGFR-TKI were also assessed in vitro. The in vivo combined antitumor effect of EGFR-TKI and FP-PDT was then evaluated. The results revealed that FOLR1 and EGFR were expressed in 79 and 89% of MPM samples, respectively. In addition, intracellular uptake of FP corresponded well with FOLR1 expression. When MPM cells were incubated with FP and then irradiated at 671 nm, there was significant in vitro cell death, which was inhibited in the presence of free folic acid, thus suggesting the specificity of FPs. FOLR1 targeting resulted in disassembly of the porphysomes and subsequent fluorescence activation in intrathoracic disseminated MPM tumors, as demonstrated by ex vivo tissue imaging. FP-PDT resulted in significant cellular damage and apoptosis in vivo. Furthermore, the combination of pretreatment with EGFR-TKI and FP-PDT induced a marked improvement of treatment responses. In conclusion, FP-based PDT induced selective destruction of MPM cells based on FOLR1 targeting, and pretreatment with EGFR-TKI further enhanced the therapeutic response.

Experimental study of the inhibition effect of CXCL12/CXCR4 in malignant pleural mesothelioma

Previous studies have demonstrated that CXCL12/CXCR4 axis is closely related to tumors such as malignant pleural mesothelioma (MPM). This research was conducted in order to detect whether CXCL12/CXCR4 inhibitors could restrain MPM and have a synergistic effect with chemotherapy, also to investigate the relationship of CXCL12/CXCR4 with other gene expressions in MPM. Forty mice were injected MPM cells and randomly divided into four groups: the PBS (control group), AMD3100 (CXCR4-CXCL12 antagonist), pemetrexed and AMD3100 plus pemetrexed. The mice were treated respectively for duration of 3 weeks. The size, bioluminescence and weight of tumors were measured. The differences between gene expressions in each group were analyzed. The tumor weights of each treatment group were lower than that of the control group (p<0.05). The bioluminescence of the tumor of the AMD3100 treatment group and the AMD3100 plus pemetrexed treatment group were lower than that of the control group (p<0.05), and AMD3100 was shown to have synergistic effects with pemetrexed (p<0.05). Among the 2.5 billion genes, several hundreds of genes expressed differently between groups. Results show that AMD3100 and pemetrexed can inhibit the growth of MPM in vivo, also that there is a better result if both are used together. Our findings suggest that CXCL12/CXCR4 axis affects a certain amount of gene expression in MPM.

Malignant peritoneal mesothelioma: clinical aspects, and therapeutic perspectives

Malignant peritoneal mesothelioma (MPM) is a rare disease with a wide clinical spectrum. It arises from the peritoneal lining and commonly presents with diffuse, extensive spread throughout the abdomen and, more rarely, metastatic spread beyond the abdominal cavity. Computed tomography, magnetic resonance imaging and positron-emission tomography are important diagnostic tools used for the preoperative staging of MPM. The definitive diagnosis is based on histopathological analysis, mainly via immunohistochemistry. In this regard, paired-box gene 8 negativity represents a useful diagnostic biomarker for differentiating MPM from ovarian carcinoma. In addition, BRCA1-associated protein-1 (BAP1) loss is specific to MPM and allows it to be distinguished from both benign mesothelial lesions and ovarian serous tumors. Cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) has become an increasingly important therapeutic approach, while systemic therapies are still being developed. Histology, Ki-67, completeness of cytoreduction, age, sex, and baseline thrombocytosis are commonly used to optimize patient selection for CRS with HIPEC. Additionally, it is well recognized that, compared to other subtypes, an epithelial morphology is associated with a favorable prognosis, whereas baseline thrombocytosis predicts an aggressive biologicalbehavior. Platelets and other immunologic cytokines have been evaluated as potential novel therapeutic targets. Epigenetic modifiers, including BAP1, SETD2 and DDX3X, are crucial in mesothelial tumorigenesis and provide opportunities for targeted treatment. Overexpression of the closely interacting phosphoinositide 3-kinase (PI3K) and the mammalian target of rapamycin (mTOR) pathways appears crucial in regulation of the malignant phenotype. The use of targeted therapies with PI3K-mTOR-based inhibitors requires further clinical assessment as a novel approach.

Factors influencing malignant mesothelioma survival: a retrospective review of the National Mesothelioma Virtual Bank cohort

Background: Malignant mesothelioma (MM) is a rare but deadly malignancy with about 3,000 new cases being diagnosed each year in the US.  Very few studies have been performed to analyze factors associated with mesothelioma survival, especially for peritoneal presentation. The overarching aim of this study is to examine survival of the cohort of patients with malignant mesothelioma enrolled in the National Mesothelioma Virtual Bank (NMVB).   Methods:  888 cases of pleural and peritoneal mesothelioma cases were selected from the NMVB database, which houses data and associated biospecimens for over 1400 cases that were diagnosed from 1990 to 2017. Kaplan Meier's method was performed for survival analysis. The association between prognostic factors and survival was estimated using Cox Hazard Regression method and using R software for analysis. Results: The median overall survival (OS) rate of all MM patients, including pleural and peritoneal mesothelioma cases is 15 months (14 months for pleural and 31 months for peritoneal).  Significant prognostic factors associated with improved survival of malignant mesothelioma cases in this NMVB cohort were younger than 45, female gender, epithelioid histological subtype, stage I, peritoneal occurrence, and having combination treatment of surgical therapy with chemotherapy. Combined surgical and chemotherapy treatment was associated with improved survival of 23 months in comparison to single line therapies. Conclusions: There has not been improvement in the overall survival for patients with malignant mesothelioma over many years with current available treatment options. Our findings show that combined surgical and chemotherapy treatment in peritoneal mesothelioma is associated with improved survival compared to local therapy alone.

Factors influencing malignant mesothelioma survival: a retrospective review of the National Mesothelioma Virtual Bank cohort

Background: Malignant mesothelioma (MM) is a rare but deadly malignancy with about 3,000 new cases being diagnosed each year in the US.  Very few studies have been performed to analyze factors associated with mesothelioma survival, especially for peritoneal presentation. The overarching aim of this study is to examine survival of the cohort of patients with malignant mesothelioma enrolled in the National Mesothelioma Virtual Bank (NMVB).   Methods:  888 cases of pleural and peritoneal mesothelioma cases were selected from the NMVB database, which houses data and associated biospecimens for over 1400 cases that were diagnosed from 1990 to 2017. Kaplan Meier's method was performed for survival analysis. The association between prognostic factors and survival was estimated using Cox Hazard Regression method and using R software for analysis. Results: The median overall survival (OS) rate of all MM patients, including pleural and peritoneal mesothelioma cases is 15 months (14 months for pleural and 31 months for peritoneal).  Significant prognostic factors associated with improved survival of malignant mesothelioma cases in this NMVB cohort were younger than 45, female gender, epithelioid histological subtype, stage I, peritoneal occurrence, and having combination treatment of surgical therapy with chemotherapy. Combined surgical and chemotherapy treatment was associated with improved survival of 23 months in comparison to single line therapies. Conclusions: There has not been improvement in the overall survival for patients with malignant mesothelioma over many years with current available treatment options. Our findings show that combined surgical and chemotherapy treatment in peritoneal mesothelioma is associated with improved survival compared to local therapy alone.

Factors influencing malignant mesothelioma survival: a retrospective review of the National Mesothelioma Virtual Bank cohort

Background: Malignant mesothelioma (MM) is a rare but deadly malignancy with about 3,000 new cases being diagnosed each year in the US.  Very few studies have been performed to analyze factors associated with mesothelioma survival, especially for peritoneal presentation. The overarching aim of this study is to examine survival of the cohort of patients with malignant mesothelioma enrolled in the National Mesothelioma Virtual Bank (NMVB).  

Methods:  888 cases of pleural and peritoneal mesothelioma cases were selected from the NMVB database, which houses data and associated biospecimens for over 1400 cases that were diagnosed from 1990 to 2017. Kaplan Meier’s method was performed for survival analysis. The association between prognostic factors and survival was estimated using Cox Hazard Regression method and using R software for analysis.

Results: The median overall survival (OS) rate of all MM patients, including pleural and peritoneal mesothelioma cases is 15 months (14 months for pleural and 31 months for peritoneal).  Significant prognostic factors associated with improved survival of malignant mesothelioma cases in this NMVB cohort were younger than 45, female gender, epithelioid histological subtype, stage I, peritoneal occurrence, and having combination treatment of surgical therapy with chemotherapy. Combined surgical and chemotherapy treatment was associated with improved survival of 23 months in comparison to single line therapies.

Conclusions: There has not been improvement in the overall survival for patients with malignant mesothelioma over many years with current available treatment options. Our findings show that combined surgical and chemotherapy treatment in peritoneal mesothelioma is associated with improved survival compared to local therapy alone.

Biomarkers for Early Diagnosis and Prognosis of Malignant Pleural Mesothelioma: The Quest Goes on

Malignant pleural mesothelioma (MM) is a highly aggressive tumor characterized by a poor prognosis. Although its carcinogenesis mechanism has not been strictly understood, about 80% of MM can be attributed to occupational and/or environmental exposure to asbestos fibers. The identification of non-invasive molecular markers for an early diagnosis of MM has been the subject of several studies aimed at diagnosing the disease at an early stage. The most studied biomarker is mesothelin, characterized by a good specificity, but it has low sensitivity, especially for non-epithelioid MM. Other protein markers are Fibulin-3 and osteopontin which have not, however, showed a superior diagnostic performance. Recently, interesting results have been reported for the HMGB1 protein in a small but limited series. An increase in channel proteins involved in water transport, aquaporins, have been identified as positive prognostic factors in MM, high levels of expression of aquaporins in tumor cells predict an increase in survival. MicroRNAs and protein panels are among the new indicators of interest. None of the markers available today are sufficiently reliable to be used in the surveillance of subjects exposed to asbestos or in the early detection of MM. Our aim is to give a detailed account of biomarkers available for MM.

New Perspectives on Diagnosis and Therapy of Malignant Pleural Mesothelioma

Malignant pleural mesothelioma (MPM) is a rare, but severe form of cancer, with an incidence that varies significantly within and among different countries around the world. It develops in about one to two persons per million of the general population, leading to thousands of deaths every year worldwide. To date, the MPM is mostly associated with occupational asbestos exposure. Asbestos represents the predominant etiological factor, with approximately 70% of cases of MPM with well-documented occupational exposure to asbestos, with the exposure time, on average greater than 40 years. Environmental exposure to asbestos is increasingly becoming recognized as a cause of mesothelioma, together with gene mutations. The possible roles of other cofactors, such as viral infection and radiation exposure, are still debated. MPM is a fatal tumor. This cancer arises during its early phase without clinical signs. Consequently, its diagnosis occurs at advanced stages. Standard clinical therapeutic approaches include surgery, chemo- and radiotherapies. Preclinical and clinical researches are making great strides in the field of this deadly disease, identifying new biomarkers and innovative therapeutic approaches. Among the newly identified markers and potential therapeutic targets, circulating microRNAs and the Notch pathway represent promising avenues that could result in the early detection of the tumor and novel therapeutic approaches.

Expression analysis of HMGB1 in histological samples of malignant pleural mesothelioma

AIMS

High mobility group box 1 (HMGB1) is a chromatin structural protein, expressed ubiquitously in the nuclei of mammalian cells. When transported extracellularly, it acts as a tumour suppressor and oncogenic protein. In malignant pleural mesothelioma (MPM), high serum levels of HMGB1 have been related to a poor prognosis. Conversely, the significance of HMGB1 expression in MPM tissues is still unclear.

METHODS AND RESULTS

Biopsy samples from 170 patients with MPM were assessed by immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR) to evaluate HMGB1 protein and gene expression. The expression level of HMGB1 protein was scored using a semiquantitative system that sums the intensity (0-3) and the percentage (from 0 to 4) of positively stained cells in nuclei, cytoplasm and in both. The final score was considered as high (>3) or low (<3) expression. Gene expression levels were calculated using the ΔΔC_t method. High expression levels of HMGB1 as total (P = 0.0011) and cytoplasmic score (P = 0.0462) were related to a worse disease-specific survival (DSS) in the entire cohort and in the clinicopathological subgroups. No significant correlation was found between HMGB1 gene expression and DSS.

CONCLUSIONS

These findings indicate that HMGB1 may be a useful prognostic biomarker in MPM when detected by immunohistochemistry. Conversely, as it is also expressed in normal and reactive mesothelial cells, HMGB1 cannot be considered a diagnostic biomarker in histological samples of mesothelioma.

Diagnostic value of microRNAs in asbestos exposure and malignant mesothelioma: systematic review and qualitative meta-analysis

Background

Asbestos is a harmful and exceptionally persistent natural material. Malignant mesothelioma (MM), an asbestos-related disease, is an insidious, lethal cancer that is poorly responsive to current treatments. Minimally invasive, specific, and sensitive biomarkers providing early and effective diagnosis in high-risk patients are urgently needed. MicroRNAs (miRNAs, miRs) are endogenous, non-coding, small RNAs with established diagnostic value in cancer and pollution exposure. A systematic review and a qualitative meta-analysis were conducted to identify high-confidence miRNAs that can serve as biomarkers of asbestos exposure and MM.

Methods

The major biomedical databases were systematically searched for miRNA expression signatures related to asbestos exposure and MM. The qualitative meta-analysis applied a novel vote-counting method that takes into account multiple parameters. The most significant miRNAs thus identified were then subjected to functional and bioinformatic analysis to assess their biomarker potential.

Results

A pool of deregulated circulating and tissue miRNAs with biomarker potential for MM was identified and designated as “mesomiRs” (MM-associated miRNAs). Comparison of data from asbestos-exposed and MM subjects found that the most promising candidates for a multimarker signature were circulating miR-126-3p, miR-103a-3p, and miR-625-3p in combination with mesothelin. The most consistently described tissue miRNAs, miR-16-5p, miR-126-3p, miR-143-3p, miR-145-5p, miR-192-5p, miR-193a-3p, miR-200b-3p, miR-203a-3p, and miR-652-3p, were also found to provide a diagnostic signature and should be further investigated as possible therapeutic targets.

Conclusion

The qualitative meta-analysis and functional investigation confirmed the early diagnostic value of two miRNA signatures for MM. Large-scale, standardized validation studies are needed to assess their clinical relevance, so as to move from the workbench to the clinic.

Multiple intracranial metastases from postoperative giant sarcomatoid malignant pleural mesothelioma: A case report and literature review

Sarcomatoid malignant pleural mesothelioma (SMPM) is a rare tumor with poor response to treatment and a dismal prognosis. Distant metastases are not uncommon and usually appear at the late stages of the disease. However, cerebral metastases have rarely been documented. We herein report a case of a giant sarcomatoid carcinoma of the pleura in a 41-year-old male patient with no history of exposure to asbestos, who presented with a chief complaint of left-sided chest pain for 1 month. Extrapleural pneumonectomy and rib excision were performed. At 5 months after the surgery, the patient was diagnosed with multiple intracranial metastatic neoplasms and succumbed to the disease soon thereafter. The aim of the present case report was to emphasize this rare metastatic pattern and aggressive clinical course of SMPM, with a supplementary review of the previously published literature.

Clinical evaluation of circulating miR-548a-3p and -20a expression in malignant pleural mesothelioma patients

AIM

miRNAs may act as promising diagnostic and prognostic biomarkers of mesothelioma. This study integrates serum  miR-548a-3p and miR-20a expression based on in silico data analysis followed by clinical validation in malignant mesothelioma patients (malignant pleural mesothelioma [MPM]).

PATIENTS & METHODS

Serum miR-548a-3p and  miR-20a level was assessed in the serum of patients with MPM, chronic asbestos exposure and healthy volunteers by quantitative real-time PCR.

RESULTS

The expression of serum miR-548a-3p and  miR-20a was positive in 91.6 and 96.7% MPM patients, respectively. Both miRNAs were able to segregate between cases and controls. The sensitivity of the combined chosen serum miRNAs reached 100% in the diagnosis of MPM.

CONCLUSION

The current work revealed that sera miR-548a-3p and miR-20a may serve as promising novel diagnostic tools for MPM.

Malignant mesothelioma as a difficult interdisciplinary problem

The authors of the present report review the etiology and clinical symptoms of malignant pleural mesothelioma (MPM) as well as diagnostic techniques (both radiological and biomarkers) used for its detection. Subsequently, they present methods of multimodal treatment (surgery, chemotherapy, and radiotherapy) recommended by the International Mesothelioma Interest Group (IMIG). Finally, they discuss complications and long-term results associated with these methods of MPM treatment.

Review of malignant pleural mesothelioma survival after talc pleurodesis or surgery

Malignant pleural mesothelioma (MPM) is an aggressive tumor and the prognosis is still dismal despite the various proposed multimodal treatment plans. Currently, new palliative treatments, such as talc pleurodesis, are being explored besides traditional surgery. This review reports survival rates after talc pleurodesis in comparison to surgery in patients with malignant pleural mesothelioma. A systematic literature search yielded 49 articles eligible for this review. The mean survival in the talc pleurodesis group was 14 months compared to 17 and 24 months for the pleurectomy decortication (P/D) group and extrapleural pneumonectomy (EPP) group, respectively. Few studies reported on the 1-, 2-year overall survival for the talc pleurodesis group and the results were very heterogeneous. The pooled 1-year overall survival for the P/D and EPP groups were 55% [credibility limits (CL): 21-87%] and 67% (CL: 3-89%), the pooled 2-year overall survival were 32% (CL: 8-63%) and 36% (CL: 8-54%), respectively. The pooled 1- and 2-year survival for surgery independently from the type of surgery were 62% (CL: 38-84%) and 34% (CL: 16-54%). There was significant heterogeneity in all the analyses. This review shows that there is limited research on the survival rate after talc pleurodesis compared to surgery in the treatment of malignant pleural mesothelioma. A comparison study is necessary to accurately assess the best way to treat MPM patients, including assessment of the quality of life after treatment as an outcome measure.

Targeting YAP in malignant pleural mesothelioma

Malignant mesothelioma is an aggressive cancer that is resistant to current therapy. The poor prognosis of mesothelioma has been associated with elevated Yes-associated protein (YAP) activity. In this study, we evaluated the effect of targeting YAP in mesothelioma. First, we comprehensively studied YAP activity in five mesothelioma cell lines (211H, H2052, H290, MS-1 and H2452) and one normal mesothelial cell line (LP9). We found decreased phospho-YAP to YAP protein ratio and consistently increased GTIIC reporter activity in 211H, H2052 and H290 compared to LP9. The same three cell lines (IC50 s < 1 μM) were more sensitive than LP9 (IC50 = 3.5 μM) to the YAP/TEAD inhibitor verteporfin. We also found that verteporfin significantly reduced YAP protein level, mRNA levels of YAP downstream genes and GTIIC reporter activity in the same three cell lines, indicating inhibition of YAP signaling by verteporfin. Verteporfin also impaired invasion and tumoursphere formation ability of H2052 and H290. To validate the effect of specific targeting YAP in mesothelioma cells, we down-regulated YAP by siRNA. We found siYAP significantly decreased YAP transcriptional activity and impaired invasion and tumoursphere formation ability of H2052 and H290. Furthermore, forced overexpression of YAP rescued GTIIC reporter activity and cell viability after siYAP targeting 3'UTR of YAP. Finally, we found concurrent immunohistochemistry staining of ROCK2 and YAP (P < 0.05). Inhibition of ROCK2 decreased GTIIC reporter activity in H2052 and 211H suggesting that Rho/ROCK signaling also contributed to YAP activation in mesothelioma cells. Our results indicate that YAP may be a potential therapeutic target in mesothelioma.

Hyaluronic acid enhances cell migration and invasion via the YAP1/TAZ-RHAMM axis in malignant pleural mesothelioma

Most malignant mesotheliomas (MPMs) frequently show activated forms of Yes-associated protein 1 (YAP1) and transcriptional co-activator with PDZ-binding motif (TAZ), which transcriptionally regulates the receptor for hyaluronic acid-mediated motility (RHAMM). As RHAMM is involved in cell migration and invasion in various tumors, we speculated that hyaluronic acid (HA) in pleural fluid might affect the progression of mesothelioma by stimulating cell migration and invasion through RHAMM. The level of RHAMM expression was decreased by YAP1/TAZ knockdown, and conversely increased by forced expression of the active form of YAP1, suggesting that RHAMM was regulated by YAP1/TAZ in MPM cells. Cell migration and invasion were also decreased by YAP1/TAZ or RHAMM knockdown. Notably, HA treatment increased cell motility and invasion, and this was abolished by RHAMM knockdown, suggesting that HA may augment local progression of MPM cells via RHAMM. Furthermore, treatment with fluvastatin, which regulates RHAMM transcription by modulating YAP1/TAZ activity, decreased the motility and invasion of MPM cells. Collectively, these data suggest that HA is an “unfavorable” factor because it promotes malignancy in mesothelioma and that the YAP1/TAZ-RHAMM axis may have potential value as a therapeutic target for inhibition of disease progression in MPM.

Asbestos and the lung: highlights of a detrimental relationship

“Asbestos” is a term used to characterise a number of natural mineral fibres of silica that can be categorised according to their structure in the serpentine-type fibres, mainly represented by chrysotile, and the amphibole-type fibres, which include crocidolite, amosite, anthophyllite, actinolite and tremolite [1]. Due to its remarkable durability and fire resistance, asbestos has been used in pottery and clothing since for at least 4500 years. However, modern commercial production of asbestos began during the second half of the 19th century when industry started to exploit its unique chemical characteristics for manufacturing various products, such as pipe insulation, brake linings, cement pipes, protective clothing, etc. With the increasing use of such materials, individuals working in the construction (e.g. builders, plumbers, etc.) and ship building (e.g. dockyard workers) industries began to be exposed to high concentrations of inhaled asbestos fibres. Approximately 50–70 years after the introduction of asbestos in commercial use, the first reports of asbestos-related diseases emerged [1]. Since then, multiple studies have connected asbestos exposure with a variety of malignant and non-malignant lung disorders.

Novel aspects of the pathogenesis of asbestos-related diseases are still coming to lighthttp://ow.ly/EPDa30e8JqK

Promising investigational drug candidates in phase I and phase II clinical trials for mesothelioma

INTRODUCTION

Malignant mesothelioma is a rare and lethal malignancy primarily affecting the pleura and peritoneum. Mesothelioma incidence is expected to increase worldwide and current treatments remain ineffective, leading to poor prognosis. Within this article potential targets to improve the quality of life of the patients and assessment of further avenues for research are discussed. Areas covered: This review highlights emerging therapies currently under investigation for malignant mesothelioma with a specific focus on phase I and phase II clinical trials. Three main areas are discussed: immunotherapy (immune checkpoint blockade and cancer vaccines, among others), multitargeted therapy (such as targeting pro-angiogenic genes) and gene therapy (such as suicide gene therapy). For each, clinical trials are described to detail the current or past investigations at phase I and II. Expert opinion: The approach of applying existing treatments from other cancers does not show significant benefit, with the most promising outcome being an increase in survival of 2.7 months following combination of chemotherapy with bevacizumab. It is our opinion that the hypoxic microenvironment, the role of the stroma, and the metabolic status of mesothelioma should all be assessed and characterised to aid in the development of new treatments to improve patient outcomes.

A pilot study of zoledronic acid in the treatment of patients with advanced malignant pleural mesothelioma

Purpose

Malignant pleural mesothelioma (MPM) is a rare malignancy with a dismal median survival of <12 months with current therapy. Single and combination chemotherapy regimens have shown only modest clinical benefit. In preclinical studies, nitrogen-containing bisphosphonates (zoledronic acid) inhibit growth of mesothelioma cells by different mechanisms: inhibition of mevalonate pathway, inhibition of angiogenesis, activation of apoptosis through caspase activation, and alteration in activity of matrix metalloproteinases, thereby affecting invasiveness of cancer cells.

Patients and methods

We investigated the role of zoledronic acid in a pilot, single-arm trial of MPM patients with Eastern Cooperative Oncology Group (ECOG) performance status (PS) 0–2 who had progressed on prior treatments or had not received systemic therapy due to poor PS. Primary end point was composite response rate by modified response evaluation criteria in solid tumors and/or metabolic response by 2-deoxy-2-[fluorine-18]fluoro-d-glucose (¹⁸F-FDG) positron emission tomography criteria. Secondary end points were progression-free survival (PFS) and overall survival (OS). Exploratory end points include the effect of zoledronic acid therapy on vascular endothelial growth factor (VEGF), basic fibroblast growth factor, interleukin 8, transforming growth factor beta, mesothelin, and osteopontin levels.

Results

Eight male patients (median age of 62 years) with the following clinical characteristics were treated; ECOG PS was 0–2, 75% with epithelioid type, and 62% had prior chemotherapy Overall composite response rate was 12.5% and the clinical benefit rate (response + stable disease) was 37.5%. Median PFS was 2 months (0.5–21 months) and median OS was 7 months (0.8–28 months). No treatment-related toxicities were observed. Lower VEGF levels were predictive of favorable response and mesothelin levels correlated with disease course.

Conclusion

Zoledronic acid shows modest clinical activity without significant toxicity in patients with advanced MPM.

Network of microRNA, transcription factors, target genes and host genes in human mesothelioma

Significant progress has been made into the elucidation of the etiology of mesothelioma at the level of the genes and miRNA. Nevertheless, researchers in this field remain unable to systematically construct a network that demonstrates the specific relationships between genes, miRNA and transcription factors (TFs). TFs are key regulatory elements that control gene expression. In the present study, according to the transcriptional regulatory rule, three regulatory networks were constructed using experimentally validated elements to explore the pathogenesis of mesothelioma. We focused on the regulatory relationship between the miRNA and its host gene, the miRNA and its target gene, and the miRNA and TFs. Expressed, related and global networks were constructed, and the similarities and differences between them were analyzed. Notably, the differentially expressed network used in the present study, which was based on experimentally validated data, contained numerous incorrect expression signal pathways for the pathogenesis of mesothelioma. In theory, if these errors are corrected, this cancer may be prevented or cured. Subsequent analysis of the differentially expressed nodes and pathways may help to explain the pathogenesis of mesothelioma. Notably, some of these exhibited a self-adaption relationship, which was detected by listing the upstream and downstream elements in a table with differentially expressed genes and miRNA. The findings of the present study demonstrated detailed transcriptional regulation, which may serve as a reference to aid further elucidation of the pathogenesis of mesothelioma.

The Emerging Role of TRAF7 in Tumor Development

The seven members of the tumor necrosis factor receptor (TNF-R)-associated factor (TRAF) family of intracellular proteins were originally discovered and characterized as signaling adaptor molecules coupled to the cytoplasmic regions of receptors of the TNF-R superfamily. Functionally, TRAFs act both as a scaffold and/or enzymatic proteins to regulate activation of mitogen-activated protein kinases (MAPKs) and transcription factors of nuclear factor-κB family (NF-κB). Given the wide variety of stimuli intracellularly conveyed by TRAF proteins, they are physiologically involved in multiple biological processes, including embryonic development, tissue homeostasis, and regulation of innate and adaptive immune responses. In the last few years, it has become increasingly evident the involvement of TRAF7, the last member of the TRAF family to be discovered, in the genesis and progression of several human cancers, placing TRAF7 in the spotlight as a novel tumor suppressor protein. In this paper, we review and discuss the literature recently produced on this subject. J. Cell. Physiol. 232: 1233-1238, 2017. © 2016 The Authors. Journal of Cellular Physiology Published by Wiley Periodicals, Inc.

Immunohistochemical evaluation of two antibodies against PD-L1 and prognostic significance of PD-L1 expression in epithelioid peritoneal malignant mesothelioma: A RENAPE study

BACKGROUND

Epithelioid peritoneal malignant mesothelioma (EPMM) is the most common subtype of this aggressive tumor. We compared two antibodies against PD-L1, a recent theranostic biomarker, and evaluated the prognostic value of PD-L1 expression by mesothelial and immune cells in EPMM.

METHODS

Immunohistochemistry was performed on 45 EPMM. Clinical and pathological data were extracted from the RENAPE database. Using E1L3N and SP142 clones, inter-observer agreement, PD-L1 expression by mesothelial and immune cells and inter-antibody agreement were evaluated. The prognostic relevance of PD-L1 expression was evaluated in 39 EPMM by univariate and multivariate analysis of overall survival (OS) and progression-free survival (PFS).

RESULTS

Inter-observer agreement on E1L3N immunostaining was moderate for mesothelial and immune cells, and fair for mesothelial and poor for immune cells using SP142. Using E1L3N, 31.1% of mesothelial and 15.6% of immune cells expressed PD-L1, and 22.2% of mesothelial and 26.7% of immune cells using SP142. Inter-antibody agreement was moderate. In most positive cases, 1-5% of tumor cells were positive. Using E1L3N, PD-L1 expression by lymphocytes was associated with better OS and PFS by both univariate and multivariate analysis. Cytoreductive surgery with hyperthermic intraperitoneal chemotherapy predicted better prognosis than other treatments. Solid subtype was an independent prognostic factor for worse OS.

CONCLUSION

E1L3N appeared easier to use than SP142 to evaluate PD-L1 expression. A minority of EPMM expressed PD-L1, and only a few cells were positive. PD-L1 expression by immune cells evaluated with E1L3N was an independent prognostic factor in EPMM.

Risk factors for malignant mesothelioma in people with no known exposure to asbestos

OBJECTIVES

Malignant mesothelioma (MM) is a rare and generally fatal cancer, usually caused by asbestos, although about 5-10% of cases report no asbestos exposure. This study aimed to identify sources whereby people in Western Australia (WA) may be unknowingly exposed to asbestos or to other exposures which may cause MM.

METHODS

Cases with no known asbestos exposure were selected from the WA Mesothelioma Register (WAMR). Matched controls were selected from hospital patients admitted for conditions unrelated to asbestos. Occupational histories were coded by an industrial hygienist. Data were analyzed using conditional logistic regression.

RESULTS

Thirty-eight MM participants and 134 controls were recruited. Risk of MM was increased (OR = 3.1, 95%CI 1.0-9.6) after no known, but likely, exposure to asbestos at work.

CONCLUSIONS

Because of its extensive use, few people in WA have never been exposed to asbestos. Unrecognized exposure may cause most MM cases initially regarded as "no exposure." Am. J. Ind. Med. 60:432-436, 2017. © 2017 Wiley Periodicals, Inc.

Pericardial mesothelioma presenting as a suspected ST-elevation myocardial infarction

Primary cardiac and pericardial tumors are rare entities with an autopsy frequency of 0.001-0.03%. Metastases to the heart and pericardium are much more common than primary tumors. Malignant pericardial mesotheliomas account for up to 50% of primary pericardial tumors. We report the case of a 75-year-old woman with hypertension, dyslipidemia and atrial fibrillation who went to the emergency department due to nonspecific thoracic discomfort of over six hours duration associated with syncope. Physical examination revealed a low-amplitude arrhythmic pulse, no heart murmurs and no signs of pulmonary congestion. The ECG revealed atrial fibrillation with ST-segment elevation in V2-V6, I and aVL. The patient was transferred for emergent coronary angiography, which revealed a long stenosis in the mid-distal portion of the left anterior descending artery. The echocardiogram showed a large pericardial effusion with diffuse thickening of the myocardium. Due to worsening hemodynamics, cardiac rupture was suspected and the patient underwent urgent sternotomy and pericardiotomy with drainage of a large quantity of hematic fluid. The surgeons then identified a large, unresectable tumor occupying the distal half of the anterior portion of the heart. This is, to our knowledge, the first case report of primary pericardial mesothelioma presenting with suspected ST-elevation myocardial infarction. In this case, direct observation of the tumor led to biopsy and the final diagnosis. These are highly malignant tumors and when diagnosed are usually already at an advanced stage.

Progress of research on microRNAs with diagnostic value in asbestos exposure: A call for method standardization

Malignant mesothelioma (MM) is an insidious, lethal asbestos-related cancer that is poorly responsive to current treatments. Specific and sensitive biomarkers providing early MM diagnosis in exposed subjects, who are at high-risk of developing it, are sorely needed. MicroRNAs (miRNAs) are endogenous, non-coding, small RNAs with a well-established diagnostic role in cancer and pollution exposure. In a recent systematic review and qualitative meta-analysis followed by a functional investigation, we examined all the available data on the miRNA biomarkers involved in asbestos exposure and MM pathways. This invited commentary aims to provide an insightful critique into the state of the art of the research into clinically relevant miRNA biomarkers, highlighting the strengths and weaknesses of current research efforts in this field. It also reviews the suggestions advanced to improve biomarker development productivity and the translation of research results into clinical practice, stressing that multicenter multidisciplinary studies adopting standardized methods and protocol sharing are the key to move from the workbench to the clinic.

Malignant pericardial mesothelioma : A systematic review of current practice

BACKGROUND

Malignant mesothelioma is a rare but aggressive tumor, with a high misdiagnosis rate and overall bleak prognosis. In 0.7% of all cases, the origin is the pericardium.

METHODS

The present study is a review of the literature published in recent decades focusing on the advances in clinical manifestations, radiological findings, diagnosis, differential diagnosis, and treatment of malignant pericardial mesothelioma (MPM).

RESULTS

No clear relationship has been established between the etiologies and the development of MPM. Clinical symptoms and signs are nonspecific when present. The main presentations are chest pain and dyspnea. Imaging plays an important role in the detection, characterization, staging, and posttreatment follow-up. The definitive diagnosis is made on the basis of pathological findings. Chest radiography and echocardiography are common techniques used initially, but their roles are limited. Computed tomography and magnetic resonance imaging have an advantage in depicting the thickened pericardium, mediastinal lymph node, tumor, and the extension of adjacent structures. Surgery is the most important treatment modality and remains palliative in most cases, while the roles of chemo- and radiotherapy are unsatisfactory.

CONCLUSION

Clinical trials of malignant pleural and peritoneal mesothelioma remain important for MPM management. Multimodality treatment of surgery, chemotherapy, radiotherapy, and immunotherapy is expected to have a role in the treatment of MPM.

SORORIN and PLK1 as potential therapeutic targets in malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is an aggressive type of cancer of the thoracic cavity commonly associated with asbestos exposure and a high mortality rate. There is a need for new molecular targets for the development of more effective therapies for MPM. Using quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR) and an RNA interference-based screening, we examined the SORORIN gene as potential therapeutic targets for MPM in addition to the PLK1 gene, which is known for kinase of SORORIN. Following in vitro investigation of the effects of target silencing on MPM cells, cell cycle analyses were performed. SORORIN expression was analyzed immunohistochemically using a total of 53 MPM samples on tissue microarray. SORORIN was found to be overexpressed in the majority of clinical MPM samples and human MPM cell lines as determined by qRT-PCR. Gene suppression of each SORORIN and PLK1 led to growth inhibition in MPM cell lines. Knockdown of SORORIN showed an increased number of G2M-phase population and a larger nuclear size, suggesting mitotic arrest. High expression of SORORIN (SORORIN-H) was found in 50.9% of all the MPM cases, and there is a tendency towards poorer prognosis for the SORORIN-H group but the difference is not significant. Suppression of SORORIN with PLK1 inhibitor BI 6727 showed a combinational growth suppressive effect on MPM cell growth. Given high-dose PLK1 inhibitor induced drug-related adverse effects in several clinical trials, our results suggest inhibition SORORIN-PLK1 axis may hold promise for the treatment of MPMs.

The endoplasmic reticulum mitochondrial calcium cross talk is downregulated in malignant pleural mesothelioma cells and plays a critical role in apoptosis inhibition

The failure of apoptosis may contribute to the formation of cancer and to its resistance to therapy. Malignant pleural mesothelioma (MPM) is an aggressive tumor that responds poorly to standard chemo- and radio-therapies. Several studies have demonstrated that a plethora of oncogenes and tumor suppressors contribute to MPM onset/progression. Importantly, most of these genes are involved in the regulation of calcium (Ca²⁺)-handling. Cellular Ca²⁺ signaling is an important regulator of many physiological processes, and it has been widely reported to participate in the regulation of apoptotic cell death in cancer cells and tissues. However, in MPM the role of cellular Ca²⁺ has been poorly investigated. Therefore, we examined whether Ca²⁺ is involved in MPM. We found that mesothelioma cell lines and short-term cultures obtained from MPM-affected patients exhibited a critical dysregulation in Ca²⁺ signaling. We determined that this characteristic was associated with resistance to apoptotic stimuli and that correction of intracellular Ca²⁺ signaling resulted in the rescue of efficient apoptotic responses. In addition, we discovered that mitochondrial Ca²⁺-uptake plays a pivotal role as an inducer of apoptosis in MPM. Altogether, these findings suggest the identification of new MPM markers, which in turn could be potential targets for new therapeutic approaches.

Kinesin family members KIF11 and KIF23 as potential therapeutic targets in malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is a rare and aggressive form of cancer commonly associated with asbestos exposure that stems from the thoracic mesothelium with high mortality rate. Currently, treatment options for MPM are limited, and new molecular targets for treatments are urgently needed. Using quantitative reverse transcription-polymerase chain reaction (RT-PCR) and an RNA interference-based screening, we screened two kinesin family members as potential therapeutic targets for MPM. Following in vitro investigation of the target silencing effects on MPM cells, a total of 53 MPMs were analyzed immunohistochemically with tissue microarray. KIF11 and KIF23 transcripts were found to be overexpressed in the majority of clinical MPM samples as well as human MPM cell lines as determined by quantitative RT-PCR. Gene knockdown in MPM cell lines identified growth inhibition following knockdown of KIF11 and KIF23. High expression of KIF11 (KIF11-H) and KIF23 (KIF23-H) were found in 43.4 and 50.9% of all the MPM cases, respectively. Patients who received curative resection with tumors displaying KIF23-H showed shorter overall survival (P=0.0194). These results provide that inhibition of KIF11 and KIF23 may hold promise for treatment of MPMs, raising the possibility that kinesin-based drug targets may be developed in the future.

Reactive oxygen species a double-edged sword for mesothelioma

It is well known that oxidative stress can lead to chronic inflammation which, in turn, could mediate most chronic diseases including cancer. Oxidants have been implicated in the activity of crocidolite and amosite, the most powerful types of asbestos associated to the occurrence of mesothelioma. Currently rates of mesothelioma are rising and estimates indicate that the incidence of mesothelioma will peak within the next 10-15 years in the western world, while in Japan the peak is predicted not to occur until 40 years from now. Although the use of asbestos has been banned in many countries around the world, production of and the potentially hazardous exposure to asbestos is still present with locally high incidences of mesothelioma. Today a new man-made material, carbon nanotubes, has arisen as a concern; carbon nanotubes may display 'asbestos-like' pathogenicity with mesothelioma induction potential. Carbon nanotubes resulted in the greatest reactive oxygen species generation. How oxidative stress activates inflammatory pathways leading to the transformation of a normal cell to a tumor cell, to tumor cell survival, proliferation, invasion, angiogenesis, chemoresistance, and radioresistance, is the aim of this review.

Distinctive clinical characteristics of malignant mesothelioma in young patients

Although considered a disease of the elderly, a subset of patients with mesothelioma are young (<40 years). The goal of this study was to understand their characteristics and outcomes. The Surveillance, Epidemiology, and End Results (SEER) database was used to extract mesothelioma cases (1990-2010). We modeled Kaplan-Meyer survival curves stratified by site of disease, and age of presentation. 2% (207 of 12345) of mesothelioma patients are young. Sex distribution is comparable among the young (51% males, 49% females); males predominated (78%, 22%) in the older cohort. Frequency of pleural and peritoneal mesothelioma are similar in the young (47%, 48% respectively); pleural disease predominated in the old (90%, 9%). Cancer-directed surgeries are more frequent in the young. Regardless of histologic subtype, young patients with pleural (11 vs. 8 months) and peritoneal (not reached vs. 10 months) mesothelioma had significantly improved overall survival. In multivariate analysis, younger age was an independent prognostic factor. Although rare, mesothelioma do occur in the young; their characteristics are distinct from those of older patients. Further studies are needed to understand the interplay between genetic susceptibility and mineral fiber carcinogenesis in the pathogenesis of mesothelioma in the young.

Genome-wide analysis of abdominal and pleural malignant mesothelioma with DNA arrays reveals both common and distinct regions of copy number alteration

Malignant mesothelioma (MM) is an aggressive tumor arising from mesothelial linings of the serosal cavities. Pleural space is the most common site, accounting for about 80% of cases, while peritoneum makes up the majority of the remaining 20%. While histologically similar, tumors from these sites are epidemiologically and clinically distinct and their attribution to asbestos exposure differs. We compared DNA array-based findings from 48 epithelioid peritoneal MMs and 41 epithelioid pleural MMs to identify similarities and differences in copy number alterations (CNAs). Losses in 3p (BAP1 gene), 9p (CDKN2A) and 22q (NF2) were seen in tumors from both tumor sites, although CDKN2A and NF2 losses were seen at a higher rate in pleural disease (p<0.01). Overall, regions of copy number gain were more common in peritoneal MM, whereas losses were more common in pleural MM, with regions of loss containing known tumor suppressor genes and regions of gain encompassing genes encoding receptor tyrosine kinase pathway members. Cases with known asbestos causation (n = 32 ) were compared with those linked to radiation exposure (n = 9 ). Deletions in 6q, 14q, 17p and 22q, and gain of 17q were seen in asbestos-associated but not radiation-related cases. As reported in post-radiation sarcoma, gains outnumbered losses in radiation-associated MM. The patterns of genomic imbalances suggest overlapping and distinct molecular pathways in MM of the pleura and peritoneum, and that differences in causation (i.e., asbestos vs. radiation) may account for some of these site-dependent differences.

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.

Mesothelioma from asbestos exposures: Epidemiologic patterns and impact in the United States

Mesothelioma, a rare tumor, is highly correlated with asbestos exposure. Mesothelioma, similar to all asbestos-related diseases, is dose/intensity dependent to some degree, and studies showed the risk of mesothelioma rises with cumulative exposures. Multiple processes occur in an individual before mesothelioma occurs. The impact of mesothelioma in the United States has been continuous over the last half century, claiming between 2,000 and 3,000 lives each year. Mesothelioma is a preventable tumor that is more frequently reported as associated with asbestos exposure among men than women. However, the rate of asbestos-associated mesothelioma is on the rise among women due to better investigation into their histories of asbestos exposure. It is of interest that investigators detected asbestos-associated cases of mesothelioma in women from nonoccupational sources-that is, bystander, incidental, or take-home exposures. It is postulated that asbestos-associated mesotheliomas, in both men and women, are likely underreported. However, with the implementation of the most recent ICD-10 coding system, the correlation of mesothelioma with asbestos exposure is expected to rise to approximately 80% in the United States. This study examined the demographic and etiological nature of asbestos-related mesothelioma.