Advances in the diagnosis, evaluation, and management of malignant pleural mesothelioma

Synthetic Secoisolariciresinol Diglucoside (LGM2605) Prevents Asbestos-Induced Inflammation and Genotoxic Cell Damage in Human Mesothelial Cells

Although alveolar macrophages play a critical role in malignant transformation of mesothelial cells following asbestos exposure, inflammatory and oxidative processes continue to occur in the mesothelial cells lining the pleura that may contribute to the carcinogenic process. Malignant transformation of mesothelial cells following asbestos exposure occurs over several decades; however, amelioration of DNA damage, inflammation, and cell injury may impede the carcinogenic process. We have shown in an in vitro model of asbestos-induced macrophage activation that synthetic secoisolariciresinol diglucoside (LGM2605), given preventively, reduced inflammatory cascades and oxidative/nitrosative cell damage. Therefore, it was hypothesized that LGM2605 could also be effective in reducing asbestos-induced activation and the damage of pleural mesothelial cells. LGM2605 treatment (50 µM) of huma n pleural mesothelial cells was initiated 4 h prior to exposure to asbestos (crocidolite, 20 µg/cm2). Supernatant and cells were evaluated at 0, 2, 4, and 8 h post asbestos exposure for reactive oxygen species (ROS) generation, DNA damage (oxidized guanine), inflammasome activation (caspase-1 activity) and associated pro-inflammatory cytokine release (IL-1β, IL-18, IL-6, TNFα, and HMGB1), and markers of oxidative stress (malondialdehyde (MDA) and 8-iso-prostaglandin F2a (8-iso-PGF2α). Asbestos induced a time-dependent ROS increase that was significantly (p < 0.0001) reduced (29.4%) by LGM2605 treatment. LGM2605 pretreatment also reduced levels of asbestos-induced DNA damage by 73.6% ± 1.0%. Although levels of inflammasome-activated cytokines, IL-1β and IL-18, reached 29.2 pg/mL ± 0.7 pg/mL and 43.9 pg/mL ± 0.8 pg/mL, respectively, LGM2605 treatment significantly (p < 0.0001) reduced cytokine levels comparable to baseline (non-asbestos exposed) values (3.8 pg/mL ± 0.2 pg/mL and 5.4 pg/mL ± 0.2 pg/mL, respectively). Furthermore, levels of IL-6 and TNFα in asbestos-exposed mesothelial cells were high (289.1 pg/mL ± 2.9 pg/mL and 511.3 pg/mL ± 10.2 pg/mL, respectively), while remaining undetectable with LGM2605 pretreatment. HMGB1 (a key inflammatory mediator and initiator of malignant transformation) release was reduced 75.3% ± 0.4% by LGM2605. Levels of MDA and 8-iso-PGF2α, markers of oxidative cell injury, were significantly (p < 0.001) reduced by 80.5% ± 0.1% and 76.6% ± 0.3%, respectively. LGM2605, given preventively, reduced ROS generation, DNA damage, and inflammasome-activated cytokine release and key inflammatory mediators implicated in asbestos-induced malignant transformation of normal mesothelial cells.

Preclinical Evaluation of Podoplanin-Targeted Alpha-Radioimmunotherapy with the Novel Antibody NZ-16 for Malignant Mesothelioma

The prognosis of advanced mesothelioma is poor. Podoplanin (PDPN) is highly expressed in most malignant mesothelioma. This study aimed to evaluate the potential alpha-radioimmunotherapy (RIT) with a newly developed anti-PDPN antibody, NZ-16, compared with a previous antibody, NZ-12.

METHODS

The in vitro properties of radiolabeled antibodies were evaluated by cell binding and competitive inhibition assays using PDPN-expressing H226 mesothelioma cells. The biodistribution of ¹¹¹In-labeled antibodies was studied in tumor-bearing mice. The absorbed doses were estimated based on biodistribution data. Tumor volumes and body weights of mice treated with ⁹⁰Y- and ²²⁵Ac-labeled NZ-16 were measured for 56 days. Histologic analysis was conducted.

RESULTS

The radiolabeled NZ-16 specifically bound to H226 cells with higher affinity than NZ-12. The biodistribution studies showed higher tumor uptake of radiolabeled NZ-16 compared with NZ-12, providing higher absorbed doses to tumors. RIT with ²²⁵Ac- and ⁹⁰Y-labeled NZ-16 had a significantly higher antitumor effect than RIT with ⁹⁰Y-labeled NZ-12. ²²⁵Ac-labeled NZ-16 induced a larger amount of necrotic change and showed a tendency to suppress tumor volumes and prolonged survival than ⁹⁰Y-labeled NZ-16. There is no obvious adverse effect.

CONCLUSIONS

Alpha-RIT with the newly developed NZ-16 is a promising therapeutic option for malignant mesothelioma.

Peritoneal malignant mesothelioma: Slippery like an eel to diagnose on cytology-case series of 3 cases

INTRODUCTION

Peritoneal malignant mesothelioma is an extremely rare tumor and is a difficult diagnosis to be made on cytology alone. We report 3 cases where the cytologic features were misdiagnosed as carcinoma/lymphoma but histopathology and immunohistochemistry (IHC) established the diagnosis of malignant mesothelioma.

CLINICAL DETAILS

Case 1 was a 60-year-old man with multiloculated ascites and omental caking. Peritoneal fluid was reported as malignant on cytology but was misclassified as adenocarcinoma. Case 2, a 45-year-old man with ascites and peritoneal nodularity, radiologically mimicking peritoneal carcinomatosis, was also reported positive for malignancy on ascitic fluid cytology. Fine-needle aspiration (FNAC) from omental fat revealed signet ring cells, thus misleading to cytologic diagnosis of adenocarcinoma. Case 3 was a 63-year-old man with perisplenic mass with extensive omental caking and peritoneal nodularity that was also suspected to be peritoneal carcinomatosis on radiology. FNAC smears from perisplenic mass showed sheets of plasmacytoid cells. On cytology, the differential diagnoses offered were neuroendocrine tumor or non-Hodgkin lymphoma. The diagnosis of malignant mesothelioma was established only after IHC on histopathologic sections in all these cases. None of our patients had history of prior asbestos exposure.

CONCLUSION

In such clinical scenarios, with radiology suggesting peritoneal carcinomatosis, the cytologic features need corroboration by IHC/fluorescence in situ hybridization on cell block or biopsy to correctly identify malignant mesothelioma and differentiate it from metastatic carcinomatous deposits and benign mesothelial proliferation.

Intramedullary Metastasis to the Cervical Spinal Cord from Malignant Pleural Mesothelioma: Review of the Literature and Case Reports

Context:

Malignant mesothelioma is an aggressive tumor; median survival of patients following diagnosis is 12 months.

Aims:

Pleural malignant mesothelioma tends to spread along preexisting tissue planes and has the rare ability to spread along the nerve root into the spinal cord. In our case, there is an evidence of exceptional direct hematogenous spread to the spinal cord by the spinal branch of the intercostal arteries or the veins of Batson's plexus.

Settings and Design:

The authors report a case of intramedullary hematogenous metastasis to the cervical spinal cord from malignant mesothelioma, with a review of the literature.

Materials and Methods:

A 68-year-old male was admitted to our department because of a slowly progressive mild weakness of both low extremities, more pronounced on the left side. The patient has been treated for a malignant mesothelioma with left thoracotomy and subsequently underwent radiotherapy. Magnetic resonance imaging of the cervical-thoracic spine revealed a contrast-enhancing intramedullary expansive lesion of the left half of the spinal cord at the C6–C7 level.

Results:

The patient underwent surgical treatment through a C6–C7 laminectomy. Through a median posterior spinal cord incision, an intramedullary grayish lesion was completely removed. The paraparesis progressively improved and 20 days after surgery, the patient had regained normal lower extremity function.

Conclusions:

Malignant mesothelioma can spread to the spinal canal by the direct extension through the intervertebral foramina, by hematogenous spread to the spinal meninges, and by perineural growth along a single nerve root. The cleavage plane of the tissue may determine whether a successful gross total resection can be achieved with a good outcome for the patient.

Therapeutic efficacy evaluation of radioimmunotherapy with 90 Y-labeled anti-podoplanin antibody NZ-12 for mesothelioma

Podoplanin is a type I transmembrane sialomucin‐like glycoprotein that is highly expressed in malignant mesothelioma. The rat‐human chimeric antibody NZ‐12 has high affinity for human podoplanin and antibody‐dependent cellular cytotoxicity and is applicable for radioimmunotherapy (RIT) to enhance the antitumor effect. In the present study, we evaluated the in vivo and in vitro properties of radiolabeled NZ‐12 and the antitumor effect of RIT with ⁹⁰Y‐labeled NZ‐12 in an NCI‐H226 (H226) malignant mesothelioma xenograft mouse model. ¹¹¹In‐labeled NZ‐12 bound specifically to H226 cells with high affinity, and accumulation was high in H226 tumors but low in major organs. RIT with ⁹⁰Y‐labeled NZ‐12 significantly suppressed tumor growth and prolonged survival without body weight loss and obvious adverse effects. Higher podoplanin expression levels were observed in human mesothelioma specimens, suggesting higher tumor accumulation of ⁹⁰Y‐labeled NZ‐12 in patients compared with the H226 tumor xenografts. Our findings suggest that ⁹⁰Y‐labeled NZ‐12 is a promising RIT agent as a new therapeutic option for malignant mesothelioma that warrants further clinical studies to evaluate the dosimetry and efficacy in patients.

Relations between approved platinum drugs and non-coding RNAs in mesothelioma

Malignant mesothelioma diseases feature an increasing risk due to their severe forms and their association with asbestos exposure. Platinum(II) complexes such as cisplatin and carboplatin are clinically approved for the therapy of mesothelioma often in combination with antimetabolites such as pemetrexed or gemcitabine. It was observed that pathogenic properties of mesothelioma cells and the response of mesothelioma tumors towards platinum-based drugs are strongly influenced by non-coding RNAs, in particular, by small microRNAs (miRNAs) and long non-coding RNAs (lncRNAs). These non-coding RNAs controlled drug sensitivity and the development of tumor resistance towards platinum drugs. An overview of the interactions between platinum drugs and non-coding RNAs is given and the influence of non-coding RNAs on platinum drug efficacy in mesothelioma is discussed. Suitable non-coding RNA-modulating agents with potentially beneficial effects on cisplatin treatment of mesothelioma diseases are mentioned. The understanding of mesothelioma diseases concerning the interactions of non-coding RNAs and platinum drugs will optimize existing therapy schemes and pave the way to new treatment options in future.

Versican modulates tumor-associated macrophage properties to stimulate mesothelioma growth

Versican promotes experimental tumor growth through cell- and non cell-autonomous mechanisms. Its role in mesothelioma progression has not been investigated so far. In this study we investigated the impact of tumor-derived versican in mesothelioma progression and the underlying mechanism of its action. For this purpose, versican-silenced or control ΑΕ17 and ΑΒ1 murine mesothelioma cells were intrapleuraly injected into syngeneic mice, in order to create pleural mesotheliomas and pleural effusions. Intratumoral and pleural immune subsets were assessed using flow cytometry. Mesothelioma cells were co-cultured with syngeneic macrophages to examine versican's impact on their interaction and endothelial cells to assess the effect of versican in endothelial permeability. Versican expression was assessed in human mesotheliomas and mesothelioma-related pleural effusions and benign pleural tissue and effusions. We observed that, versican silencing reduced mesothelioma mass and pleural fluid volume by affecting tumor cell proliferation and apoptosis in vivo, while tumor cell growth remained intact in vitro, and limited pleural vascular permeability. Mice harboring versican-deficient tumors presented fewer tumor/pleural macrophages and neutrophils, and fewer pleural T-regulatory cells, compared to the control animals. Macrophages co-cultured with versican-deficient mesothelioma cells were polarized towards M1 anti-tumor phenotype and demonstrated increased tumor cell phagocytic capacity, compared to macrophages co-cultured with control tumor cells. In co-culture, endothelial monolayer permeability was less effectively stimulated by versican-deficient cells than control cells. Versican was over-expressed in human mesothelioma tissue and mesothelioma-associated effusion. In conclusion, tumor cell-derived versican stimulates mesothelioma progression by shaping a tumor friendly inflammatory milieu, mainly by blunting macrophage anti-tumor activities.

Synthetic Lignan Secoisolariciresinol Diglucoside (LGM2605) Reduces Asbestos-Induced Cytotoxicity in an Nrf2-Dependent and -Independent Manner

Asbestos exposure triggers inflammatory processes associated with oxidative stress and tissue damage linked to malignancy. LGM2605 is the synthetic lignan secoisolariciresinol diglucoside (SDG) with free radical scavenging, antioxidant, and anti-inflammatory properties in diverse inflammatory cell and mouse models, including exposure to asbestos fibers. Nuclear factor-E2 related factor 2 (Nrf2) activation and boosting of endogenous tissue defenses were associated with the protective action of LGM2605 from asbestos-induced cellular damage. To elucidate the role of Nrf2 induction by LGM2605 in protection from asbestos-induced cellular damage, we evaluated LGM2605 in asbestos-exposed macrophages from wild-type (WT) and Nrf2 disrupted (Nrf2⁻/⁻) mice. Cells were pretreated with LGM2605 (50 µM and 100 µM) and exposed to asbestos fibers (20 µg/cm²) and evaluated 8 h and 24 h later for inflammasome activation, secreted cytokine levels (interleukin-1β (IL-1β), interleukin-18 (IL-18), interleukin-6 (IL-6), and tumor necrosis factor alpha (TNFα)), cytotoxicity and cell death, nitrosative stress, and Nrf2-regulated enzyme levels. Asbestos exposure induced robust oxidative and nitrosative stress, cell death and cytotoxicity, which were equally mitigated by LGM2605. Inflammasome activation was significantly attenuated in Nrf2^−/− macrophages compared to WT, and the protective action of LGM2605 was seen only in WT cells. In conclusion, in a cell model of asbestos-induced toxicity, LGM2605 acts via protective mechanisms that may not involve Nrf2 activation.

Physicochemical and pharmacokinetic properties of polymeric films loaded with cisplatin for the treatment of malignant pleural mesothelioma

Background

Malignant mesothelioma is an invasive neoplasm arising from mesothelial surfaces of the pleural and peritoneal cavities. Mesothelioma treatment is unsatisfactory and recurrence is common. Here an innovative locoregional treatment for malignant pleural mesothelioma is presented.

Methods

Chitosan- and hyaluronate-based films were loaded with 0.5% and 4% w/w cisplatin and were studied for their physicochemical, mechanical and drug release characteristics. The performance of the drug delivery systems was assessed in vitro on A549 cells and on an orthotopic model of MPM recurrence in rats.

Results

Polysaccharide films produced were thin, flexible and resistant. Cisplatin was completely released from hyaluronic acid films within 96 hours, while drug release was found to be much more prolonged with chitosan films. The drug released from hyaluronate films was effective against A549 cell line, while for chitosan films the release was too slow to produce cytotoxicity. Similarly, cisplatin-loaded chitosan films in vivo released minimal quantities of cisplatin and induced inflammation and foreign body reaction. Cisplatin-loaded hyaluronate acid films on the contrary were able to prevent tumor recurrence. The cisplatin-loaded hyaluronate films provided higher C_max and AUC compared to a solution of cisplatin administered intrapleurally, but did not show any sign of treatment related toxicity.

Conclusions

Hyaluronate-based films appear as an optimal platform for the development of drug delivery systems suitable for the loco-regional post-surgical treatment of lung malignancies.

Turkey National Mesothelioma Surveillance and Environmental Asbestos Exposure Control Program

Malignant mesothelioma (MM) is an important health problem due to ongoing asbestos exposure. Environmental asbestos exposure leads to a high risk of MM in Turkey. The Turkish Mesothelioma Working Group and the Turkish Public Health Institute designed and performed the Turkey National Mesothelioma Surveillance and Environmental Asbestos Exposure Control Program (TUNMES-EAECP). The aim of this study was to analyze the results of the TUNMES-EAECP. Patients diagnosed with MM (code C45.0-C45.9) between 2008 and 2012 were identified. The "from case to the field" method was used to determine the villages with current or previous asbestos exposure. Special public health teams took soil samples from these villages, which were then examined using an X-ray diffractometer. Direct Standardized Average Annual Mesothelioma Incidence Rate (AMIR) and relative risk (RR) of MM were calculated. Finally, a projection on the incidence of MM between 2013 and 2033 was made. The number of confirmed MM cases was 5617 with a male to female ratio of 1.36. Mean age was 61.7 ± 13.4 (20-96) years. The median survival was eight (95% CI 7.6-8.4) months. Asbestos exposure continues in 379 villages, with 158,068 people still living in high risk areas. The standardized AMIR was 2.33/100,000 per year. The risk of MM was higher in males, in both sexes over the age of 40, in asbestos-containing provinces, and in those where the TUNMES was organized. Among the population with continuing asbestos exposure in rural areas, the number of MM cases between 2013 and 2033 was estimated as 2511. As such, the incidence of MM in Turkey is as high as in industrialized countries. Asbestos exposure in rural areas continues to be a serious problem in Turkey, which obviates the necessity for effective preventive measures.

Advances in systemic therapy for malignant mesothelioma: future perspectives

Malignant mesothelioma is a rare and aggressive form of cancer affecting the mesothelium. This mainly occupational disease is becoming more common in those countries where asbestos has been used for industrial applications. Notwithstanding the progress made in the field, patients do not survive more than 12 months on average with standard treatment. With the advent of next generation sequencing, it is now possible to study the mutational landscape of each tumor with the aim of identifying the genetic aberrations driving tumorigenesis. This review encompasses the latest research in the field, with particular attention to new chemotherapy combinatorial regimens, molecular targets and immunotherapies, providing a comprehensive picture of the current and future treatment options for malignant mesothelioma patients.

Malignant Peritoneum Mesothelioma with Hepatic Involvement: A Single Institution Experience in 5 Patients and Review of the Literature

Malignant peritoneal mesothelioma with invasion of the liver is an invariably fatal disease. We aimed to clarify the characteristics of malignant peritoneal mesothelioma cases with liver involvement. The clinical presentation, computed tomography images, and immunohistochemical and histopathological features of 5 patients with malignant peritoneal mesothelioma and liver involvement were evaluated. The diagnosis was established by imaging and immune profiles of the tumours. A review of 8 cases with primary or invading malignant mesothelioma in liver is presented. All 5 mesothelioma cases were asbestos-related. CT images of malignant peritoneal mesothelioma with the liver involvement typically showed that the lesion grew inside the liver along the capsule and was possibly accompanied by capsule breakthrough and extrahepatic infiltration. The tumours exhibited a common epithelioid appearance in all 5 patients and most cases revealed positive Cal, CK, and MC with negative CEA and HeP. Different from our findings, the review of literature revealed that most malignant mesothelioma of liver was due to primary intrahepatic malignant mesothelioma. Finally, we concluded that the diagnosis of malignant peritoneal mesothelioma cases with liver invasion is reliably achieved by the history of asbestos exposure, the characteristic CT imaging, and immune profiles of the tumours.

A pilot study of volumetric-modulated arc therapy for malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is an extremely difficult disease to treat. This pilot study investigates the feasibility of using volumetric-modulated arc therapy (VMAT) for malignant pleural mesothelioma (MPM), and compares VMAT to static field intensity-modulated radiotherapy (IMRT) for five patients. To identify the best treatment technique for MPM, in five patients, we made a representative comparative analysis of two kinds of techniques for radiation therapy planning: IMRT and VMAT. The plans were created for an Elekta Synergy linear accelerator with 6 MV photons using Oncentra version 4.3 treatment planning system. Dose prescription was 50 Gy to the average of the planning target volume (PTV). PTV coverage and homogeneity, dose of organs at risk, numbers of segments, MUs, and delivery time were evaluated for all techniques. VMAT allowed better homogeneous and conformity indices compared with IMRT (HI = 0.17 vs. 0.12, CI = 0.64 vs. 0.77, respectively, p < 0.05). VMAT plan had a significantly shorter delivery time (326 s) compared with in IMRT plans (510 s), (p < 0.05). In the dose verification, an average of 93.16% of the detector points passed the 3%/3 mmγ criterion for VMAT plans, while in IMRT plans the dose verification was 95.12%.(p > 0.05).

Asbestos Induces Oxidative Stress and Activation of Nrf2 Signaling in Murine Macrophages: Chemopreventive Role of the Synthetic Lignan Secoisolariciresinol Diglucoside (LGM2605)

The interaction of asbestos fibers with macrophages generates harmful reactive oxygen species (ROS) and subsequent oxidative cell damage that are key processes linked to malignancy. Secoisolariciresinol diglucoside (SDG) is a non-toxic, flaxseed-derived pluripotent compound that has antioxidant properties and may thus function as a chemopreventive agent for asbestos-induced mesothelioma. We thus evaluated synthetic SDG (LGM2605) in asbestos-exposed, elicited murine peritoneal macrophages as an in vitro model of tissue phagocytic response to the presence of asbestos in the pleural space. Murine peritoneal macrophages (MFs) were exposed to crocidolite asbestos fibers (20 µg/cm²) and evaluated at various times post exposure for cytotoxicity, ROS generation, malondialdehyde (MDA), and levels of 8-iso Prostaglandin F2α (8-isoP). We then evaluated the ability of LGM2605 to mitigate asbestos-induced oxidative stress by administering LGM2605 (50 µM) 4-h prior to asbestos exposure. We observed a significant (p < 0.0001), time-dependent increase in asbestos-induced cytotoxicity, ROS generation, and the release of MDA and 8-iso Prostaglandin F2α, markers of lipid peroxidation, which increased linearly over time. LGM2605 treatment significantly (p < 0.0001) reduced asbestos-induced cytotoxicity and ROS generation, while decreasing levels of MDA and 8-isoP by 71%–88% and 41%–73%, respectively. Importantly, exposure to asbestos fibers induced cell protective defenses, such as cellular Nrf2 activation and the expression of phase II antioxidant enzymes, HO-1 and Nqo1 that were further enhanced by LGM2605 treatment. LGM2605 boosted antioxidant defenses, as well as reduced asbestos-induced ROS generation and markers of oxidative stress in murine peritoneal macrophages, supporting its possible use as a chemoprevention agent in the development of asbestos-induced malignant mesothelioma.

Bioanalytical techniques for detecting biomarkers of response to human asbestos exposure

Asbestos exposure is known to cause lung cancer and mesothelioma and its health and economic impacts have been well documented. The exceptionally long latency periods of most asbestos-related diseases have hampered preventative and precautionary steps thus far. We aimed to summarize the state of knowledge on biomarkers of response to asbestos exposure. Asbestos is not present in human biological fluids; rather it is inhaled and trapped in lung tissue. Biomarkers of response, which reflect a change in biologic function in response to asbestos exposure, are analyzed. Several classes of molecules have been studied and evaluated for their potential utility as biomarkers of asbestos exposure. These studies range from small molecule oxidative stress biomarkers to proteins involved in immune responses.

Differential p16/INK4A cyclin-dependent kinase inhibitor expression correlates with chemotherapy efficacy in a cohort of 88 malignant pleural mesothelioma patients

Background:

Malignant pleural mesothelioma (MPM) is a rare and essentially incurable malignancy most often linked with occupational exposure to asbestos fibres. In common with other malignancies, the development and progression of MPM is associated with extensive dysregulation of cell cycle checkpoint proteins that modulate cell proliferation, apoptosis, DNA repair and senescence.

Methods:

The expression of cyclin-dependent kinase inhibitor p16/INK4A was evaluated by immunohistochemistry using tumour biopsy specimens from 88 MPM cases and a semi-quantitative score for p16/INK4A expression was obtained. Post-diagnosis survival and the survival benefit of chemotherapeutic intervention was correlated with p16/INK4A expression.

Results:

A low, intermediate and high score for p16/INK4A expression was observed for 45 (51.1%), 28 (31.8%) and 15 (17.1%) of the MPM cases, respectively. Those cases with intermediate or high p16/INK4A tumour expression had a significantly better post-diagnosis survival than those cases whose tumours lost p16 expression (log-rank P<0.001). Those patients with sustained p16/INK4A expression who received chemotherapy also had a better survival than those treated patients whose tumours had lost p16/INK4A expression (log-rank P<0.001).

Conclusions:

Sustained p16/INK4A expression predicts better post-diagnosis survival in MPM and also better survival following chemotherapeutic intervention.

Surgical cytoreduction restores the antitumor efficacy of a Listeria monocytogenes vaccine in malignant pleural mesothelioma

Recent studies suggest that immunotherapy may offer a promising treatment strategy for early-stage malignant pleural mesothelioma (MPM), but advanced tumor burden may limit the efficacy of immunotherapy. Therefore, we hypothesized that surgical cytoreduction could restore the efficacy of vaccine-based immunotherapy for MPM. We developed a murine model of MPM through transduction of a mesothelioma cell line with mesothelin. We used this model to evaluate the efficacy of a Listeria monocytogenes vaccine expressing mesothelin. Tumor growth was significantly inhibited at four weeks in animals vaccinated two weeks prior to tumor cell inoculation as compared to those given an empty vector control (1371 ± 420 mm(3) versus 405 ± 139 mm(3); p < 0.01). Mice vaccinated one week prior to tumor challenge also displayed significant reduction in tumor volume (1227 ± 406 mm(3) versus 309 ± 173 mm(3); p < 0.01). The vaccine had no effect when administered concurrently with tumor challenge, or after tumors were established. Flow cytometry showed reduced mesothelin expression in large tumors, as well as tumor-associated immunosuppression due to increased myeloid derived suppressor cells (MDSCs). These factors may have limited vaccine efficacy for advanced disease. Surgical cytoreduction of established tumors restored the antitumor potency of the therapeutic vaccine, with significantly reduced tumor burden at post-operative day 18 (397 ± 103 mm(3) versus 1047 ± 258 mm(3); p < 0.01). We found that surgery reduced MDSCs to levels comparable to those in tumor-naïve mice. This study demonstrates that cytoreduction surgery restores the efficacy of cancer vaccines for MPM by reducing tumor-related immunosuppression that impairs immunotherapy.

Malignant Mesothelioma Diagnosed by Bronchoscopic Biopsy

Malignant mesothelioma is a rare malignant neoplasm that arises from mesothelial surfaces of the pleural cavity, peritoneal cavity, tunica vaginalis, or pericardium. Typically, pleural fluid cytology or closed pleural biopsy, surgical intervention (video thoracoscopic biopsy or open thoracotomy) is conducted to obtain pleural tissue specimens. However, endobronchial lesions are rarely seen and cases diagnosed from bronchoscopic biopsy are also rarely reported. We reported the case of a 77-year-old male who was diagnosed as malignant mesothelioma on bronchoscopic biopsy from obstructing masses of the endobronchial lesion.

Inhibition of mesothelioma cancer stem-like cells with adenovirus-mediated NK4 gene therapy

Malignant mesothelioma (MM) is a highly invasive and chemoresistant malignancy induced by asbestos fibers. NK4, a hepatocyte growth factor antagonist and angiogenesis inhibitor, consists of the N-terminal hairpin domain and four kringle domains of the α-chain of hepatocyte growth factor. The therapeutic potential of NK4 has been demonstrated in a variety of tumor types. However, the mechanisms by which NK4 inhibits tumor growth have not been well delineated. In this study, it is shown that the NK4 adenovirus (Ad-NK4) potently inhibits cell viability, invasiveness and tumorigenicity of human MM cells. Significantly, this study demonstrates for the first time that Ad-NK4 inhibits cancer stem-like cell (CSC) properties as assessed by spheroid formation assay, side population analysis and flow cytometric sorting of CD24 cells. In addition to inhibiting phosphorylation of Met and AKT, Ad-NK4 markedly suppressed the active form of β-catenin, a key mediator of both Wnt and AKT pathways. It is further demonstrated that expression of NK4 suppresses β-catenin nuclear localization and transcriptional activity. Intriguingly, the expression levels of Oct4 and Myc, two critical stem cell factors and downstream targets of β-catenin, were also diminished by Ad-NK4. Furthermore, the strong antitumor effect of NK4 was found to be linked to its ability to inhibit CSCs as revealed by immunohistochemical examination of tumor specimens from a mouse xenograft model of human MM. These findings suggest that NK4 acts as a CSC inhibitor by impeding Met/AKT/β-catenin signaling and holds promise for achieving durable therapeutic responses in MM by constraining the CSC component of these aggressive tumors.

Malignant mesothelioma

Malignant Mesothelioma (MM) is a rare but rapidly fatal and aggressive tumor of the pleura and peritoneum with limited knowledge of its natural history. The incidence has increased in the past two decades but still it is a rare tumor. Etiology of all forms of mesothelioma is strongly associated with industrial pollutants, of which asbestos is the principal carcinogen. Mesothelioma is an insidious neoplasm arising from mesothelial surfaces i.e., pleura (65%-70%), peritoneum (30%), tunica vaginalis testis, and pericardium (1%-2%). The diagnosis of peritoneal and Pleural mesothelioma is often delayed, due to a long latent period between onset and symptoms and the common and nonspecific clinical presentation. The definite diagnosis can only be established by diagnostic laparoscopy or open surgery along with biopsy to obtain histological examination and immunocytochemical analysis. Different treatment options are available but Surgery can achieve a complete or incomplete resection and Radical resection is the preferred treatment. Chemotherapy has an important role in palliative treatment. Photodynamic therapy is also an option under trial. Patients who successfully underwent surgical resection had a considerably longer median survival as well as a significantly higher 5-year survival.

Source of Data/Study Selection: The data were collected from case reports, cross-sectional studies, Open-label studies and phase –II trials between 1973-2012.

Data Extraction: Web sites and other online resources of American college of surgeons, Medline, NCBI and Medscape resource centers were used to extract data.

Conclusion: Malignant Mesothelioma (MM) is a rare but rapidly fatal and aggressive tumor with limited knowledge of its natural history. The diagnosis of peritoneal and Pleural mesothelioma is often delayed, so level of index of suspicion must be kept high.

Malignant peritoneal mesothelioma: clinicopathological characteristics of two cases

Introduction. Peritoneal mesothelioma is a rare tumor, presenting difficulties in diagnosis and treatment. Peritoneum is the second most common area of the mesothelioma after pleura, and even synchronous pleural and peritoneal mesotheliomas are observed in 30–45% of all cases. The diagnosis may be difficult due to lack of specific symptoms and clinical findings. In addition, a delay in the diagnosis is not rare especially in the absence of previous asbestos exposure. Here we report two cases of malignant peritoneal mesotheliomas. The diagnostic and therapeutic approaches for these rare neoplasms are discussed. Case Presentation. The cases were two men (one aged 54 years old and the other 40 years old). Prolonged abdominal pain and swelling were the primary presentation symptoms and findings. The mesotheliomas were developed in the right upper quadrant of abdomen in both of the cases. Both cases were treated with surgical resection. Final diagnosis were possible with histological and immunohistochemical documentation of tumor characteristics, which were consistent with dictating a mesothelial origin. No history of asbestos exposure was reported. Conclusion. Peritoneal mesotheliomas are rare clinical entities. However, patients with prolonged abdominal pain and abdominal masses should be considered to have atypical pathologies such as peritoneal mesotheliomas.

Proteome screening of pleural effusions identifies galectin 1 as a diagnostic biomarker and highlights several prognostic biomarkers for malignant mesothelioma

Malignant mesothelioma is an aggressive asbestos-induced cancer, and affected patients have a median survival of approximately one year after diagnosis. It is often difficult to reach a conclusive diagnosis, and ancillary measurements of soluble biomarkers could increase diagnostic accuracy. Unfortunately, few soluble mesothelioma biomarkers are suitable for clinical application. Here we screened the effusion proteomes of mesothelioma and lung adenocarcinoma patients to identify novel soluble mesothelioma biomarkers. We performed quantitative mass-spectrometry-based proteomics using isobaric tags for quantification and used narrow-range immobilized pH gradient/high-resolution isoelectric focusing (pH 4–4.25) prior to analysis by means of nano liquid chromatography coupled to MS/MS. More than 1,300 proteins were identified in pleural effusions from patients with malignant mesothelioma (n = 6), lung adenocarcinoma (n = 6), or benign mesotheliosis (n = 7). Data are available via ProteomeXchange with identifier PXD000531. The identified proteins included a set of known mesothelioma markers and proteins that regulate hallmarks of cancer such as invasion, angiogenesis, and immune evasion, plus several new candidate proteins. Seven candidates (aldo-keto reductase 1B10, apolipoprotein C-I, galectin 1, myosin-VIIb, superoxide dismutase 2, tenascin C, and thrombospondin 1) were validated by enzyme-linked immunosorbent assays in a larger group of patients with mesothelioma (n = 37) or metastatic carcinomas (n = 25) and in effusions from patients with benign, reactive conditions (n = 16). Galectin 1 was identified as overexpressed in effusions from lung adenocarcinoma relative to mesothelioma and was validated as an excellent predictor for metastatic carcinomas against malignant mesothelioma. Galectin 1, aldo-keto reductase 1B10, and apolipoprotein C-I were all identified as potential prognostic biomarkers for malignant mesothelioma. This analysis of the effusion proteome furthers our understanding of malignant mesothelioma, identified galectin 1 as a potential diagnostic biomarker, and highlighted several possible prognostic biomarkers of this disease.

AHNAK is highly expressed and plays a key role in cell migration and invasion in mesothelioma

The worldwide incidence of the highly aggressive tumor mesothelioma is expected to increase. Mesothelioma is classified into three main histological subtypes: epithelioid, sarcomatoid and biphasic. Although the pathological diagnostic markers for epithelioid are established, to date no adequate marker for sarcomatoid mesothelioma has been found. Thus, a reliable diagnostic marker of sarcomatoid mesothelioma is necessary. In this study, to identify an unknown protein with 120 kDa expressed only in the mesothelioma cell line 211H, we conducted proteomic analysis and found five candidate proteins. One such protein, AHNAK, was highly expressed in all seven mesothelioma cell lines (211H, H28, H226, H2052, H2452, MESO1 and MESO4), but not in the mesothelial cell line MeT-5A by RT-PCR and immunofluorescence staining. Furthermore, we confirmed high AHNAK expression not only in xenografts but also in human mesothelioma specimens including sarcomatoid, epithelioid and biphasic mesothelioma using immunohistochemical staining. These findings suggest that AHNAK has the potential to be a new marker for detecting mesothelioma. Since AHNAK is involved in cell migration and invasion in other metastatic tumor cells, we conducted migration and invasion assays in mesothelioma cell lines. The number of migrating cells in six of seven mesothelioma cell lines and the number of invading cells in all seven cell lines were significantly increased compared with those in MeT-5A. Knockdown of AHNAK significantly reduced the cell migration and invasion ability in all seven mesothelioma cell lines. These results support further clinical evaluation of the association of AHNAK and metastasis in mesothelioma.

Hyaluronan and N-ERC/mesothelin as key biomarkers in a specific two-step model to predict pleural malignant mesothelioma

Purpose

Diagnosis of malignant mesothelioma is challenging. The first available diagnostic material is often an effusion and biochemical analysis of soluble markers may provide additional diagnostic information. This study aimed to establish a predictive model using biomarkers from pleural effusions, to allow early and accurate diagnosis.

Patients and Methods

Effusions were collected prospectively from 190 consecutive patients at a regional referral centre. Hyaluronan, N-ERC/mesothelin, C-ERC/mesothelin, osteopontin, syndecan-1, syndecan-2, and thioredoxin were measured using ELISA and HPLC. A predictive model was generated and validated using a second prospective set of 375 effusions collected consecutively at a different referral centre.

Results

Biochemical markers significantly associated with mesothelioma were hyaluronan (odds ratio, 95% CI: 8.82, 4.82–20.39), N-ERC/mesothelin (4.81, 3.19–7.93), CERC/mesothelin (3.58, 2.43–5.59) and syndecan-1 (1.34, 1.03–1.77). A two-step model using hyaluronan and N-ERC/mesothelin, and combining a threshold decision rule with logistic regression, yielded good discrimination with an area under the ROC curve of 0.99 (95% CI: 0.97–1.00) in the model generation dataset and 0.83 (0.74–0.91) in the validation dataset, respectively.

Conclusions

A two-step model using hyaluronan and N-ERC/mesothelin predicts mesothelioma with high specificity. This method can be performed on the first available effusion and could be a useful adjunct to the morphological diagnosis of mesothelioma.

Immunological effects of the TGFβ-blocking antibody GC1008 in malignant pleural mesothelioma patients

We evaluated a neutralizing anti-TGFβ antibody (GC1008) in cancer patients with malignant pleura mesothelioma (MPM). The goal of this study was to assess immunoregulatory effects in relation to clinical safety and clinical response. Patients with progressive MPM and 1-2 prior systemic therapies received GC1008 at 3mg/kg IV over 90 min every 21 d as part of an open-label, two-center Phase II trial. Following TGFβ blockade therapy, clinical safety and patient survival were monitored along with the effects of anti-TGFβ antibodies on serum biomarkers and peripheral blood mononuclear cells (PBMC). Although designed as a larger trial, only 13 patients were enrolled when the manufacturer discontinued further development of the antibody for oncology indications. All participants tolerated therapy. Although partial or complete radiographic responses were not observed, three patients showed stable disease at 3 mo. GC1008 had no effect in the expression of NK, CD4+, or CD8+ T cell activating and inhibitory markers, other than a decrease in the expression of 2B4 and DNAM-1 on NK cells. However, serum from 5 patients showed new or enhanced levels of antibodies against MPM tumor lysates as measured by immunoblotting. Patients who produced anti-tumor antibodies had increased median overall survival (OS) (15 vs 7.5 mo, p < 0.03) compared with those who did not. To our knowledge, these data represent the first immune analysis of TGFβ- blockade in human cancer patients.

Differential diagnosis of reactive mesothelial cells and malignant mesothelioma cells using the cell proliferation markers minichromosome maintenance protein 7, geminin, topoisomerase II alpha and Ki-67

OBJECTIVE

The aim of this study was to evaluate whether the immunocytochemical expression of cell proliferation markers, such as minichromosome maintenance protein 7 (MCM 7), geminin, topoisomerase II alpha (topo IIα) and Ki-67, which are different types of cell proliferation markers, could be useful for their differential diagnosis in reactive mesothelial cells and malignant mesothelioma cells obtained from body cavity fluids.

STUDY DESIGN

Samples diagnosed and later histologically confirmed as reactive mesothelial cells (39 cases) or malignant mesothelioma (32 cases) in body cavity fluids were examined. Immunocytochemical staining of MCM 7, geminin, topo IIα and Ki-67 was performed with the immunoperoxidase polymer method.

RESULTS

Labeling indices (LIs) of MCM 7 (cutoff value 20.0%; sensitivity 100%; specificity 100%), geminin (cutoff value 4.5%; sensitivity 88.0%; specificity 70.0%), topo IIα (cutoff value 11.0%; sensitivity 88.0%; specificity 92.0%) and Ki-67 (cutoff value 15.3%; sensitivity 78.0%; specificity 79.0%) of malignant mesothelioma cells were significantly higher than those of reactive mesothelial cells.

CONCLUSION

LIs of MCM 7, geminin and topo IIα can be reliable tools for the differential diagnosis of reactive mesothelial cells and malignant mesothelioma cells.

Intracavitary therapeutics for pleural malignancies

Pleural malignancies are ideal for novel therapeutic approaches because they are invariably fatal. Intrapleural (IP) chemotherapy has only marginal benefit in pleural malignancies, but may prove efficacious with hyperthermic chemotherapy administered in combination with maximal tumor debulking. IP immunotherapies may be most effective in those patients with early-stage pleural malignancy, and may prove superior to standard pleurodesis methods in control of effusion and prolongation of survival. Immunogene therapy may be unable to successfully treat bulky tumors on its own, but success may be achieved with combination approaches that combine debulking surgery and chemotherapy with IP genetic immunotherapy.

Malignant pleural mesothelioma: update on treatment options with a focus on novel therapies

There is evidence that improved treatments of malignant pleural mesothelioma are increasing the quality and quantity of life for patients with mesothelioma. Multimodality treatment programs that combine maximal surgical cytoreduction with novel forms of radiation therapy and more effective chemotherapy combinations may offer significant increases in survival for certain subgroups of patients with mesothelioma. Lung-sparing surgery may allow improvements in pulmonary function after surgery-based multimodality therapy, and potential longer overall survival than that seen with extrapleural pneumonectomy. Experimental treatments provide hope for all patients with mesothelioma, and in the future may be combined with standard therapy in multimodality protocols.

Evaluation of the efficacy of the guideline on reading CT images of malignant pleural mesothelioma with reference CT films for improving the proficiency of radiologists

PURPOSE

To assess the efficacy of the developed guideline on reading CT images of malignant pleural mesothelioma for improving radiologists' reading proficiency.

MATERIALS AND METHODS

Three radiologists independently read the CT films of 22 cases including definite mesothelioma and non-mesothelioma cases at two times before and after studying the malignant pleural mesothelioma CT Guideline. The sensitivity and specificity for mesothelioma were calculated and compared between the 1st and 2nd trials. The kappa statistics was examined for agreement with experts for mesothelioma probability and for mesothelioma features recorded by three radiologists.

RESULTS

After studying the mesothelioma CT Guideline, the sensitivity for mesothelioma shown by the three radiologists at the 2nd trial was 100%, 100% and 80%, which were higher than 80%, 85% and 60% at the 1st trial, respectively. The average kappa for agreement between radiologists and experts on dichotomized mesothelioma probability were 0.69 (good) at the 2nd trial vs. 0.38 (fair) at the 1st trial. The average kappa for the agreement with experts for each of 7 features by three radiologists were 0.52-0.80 at the 2nd trial, which were significantly higher than 0.34-0.58 at the 1st trial (Wilcoxon Signed Rank Test: P<0.01), and as to five features "unilateral pleural effusion", "nodular pleural thickening", "tumoral encasement of lung", "mediastinal pleural thickening", and "diminished lung", they achieved good agreement with average kappa of 0.61-0.80.

CONCLUSION

The developed mesothelioma CT Guideline was suggested to have substantial effect in improving the radiologists' proficiency for reading CT images of mesothelioma, and may contribute to accurate diagnosis of mesothelioma.

Sustained expression of steroid receptor coactivator SRC-2/TIF-2 is associated with better prognosis in malignant pleural mesothelioma

INTRODUCTION

Estrogen receptor beta (ERβ) overexpression by malignant pleural mesothelioma (MPM) tumor cells correlates with enhanced patient survival. ER-regulated transcription is mediated by the p160 family of steroid receptor coactivators (SRCs), and SRC isoform overexpression is associated with worse prognosis in many steroid-related malignancies. The aim of this study was to establish whether SRC isoform expression varied between individual MPM tumors with positive or negative prognostic significance.

METHODS

Immunohistochemical analysis of tumor biopsies from 89 subjects with confirmed histological diagnosis of MPM and biopsies from 3 normal control subjects was performed to detect the expression of SRC-1, SRC-2 (TIF-2), SRC-3 (AIB-1), and ERβ. Allred scores for expression of ERβ and each of the SRCs were determined, and Kaplan-Meier survival curves were calculated to correlate biomarker expression, gender, and histology type with postdiagnosis survival.

RESULTS

ERβ and all the SRCs were expressed at high levels in normal pleural mesothelium, and expression of each biomarker was reduced or lost in a subset of the MPM subjects; however, postdiagnosis survival only significantly correlated with TIF-2 expression. Low or intermediate expression of TIF-2 correlated with reduced median postdiagnosis survival (9 months) compared with those subjects whose tumors highly expressed TIF-2 (20 months) (p = 0.036, log-rank test).

CONCLUSIONS

Maintained high expression of TIF-2 in tumor cells is a positive prognostic indicator for postdiagnosis survival in patients with confirmed MPM. This is the first clinical study to correlate high TIF-2 expression with improved patient prognosis in any malignancy.

A trial of intrapleural adenoviral-mediated Interferon-α2b gene transfer for malignant pleural mesothelioma

New therapeutic strategies are needed for malignant pleural mesothelioma (MPM). We conducted a single-center, open-label, nonrandomized, pilot and feasibility trial using two intrapleural doses of an adenoviral vector encoding human IFN-α (Ad.IFN-α2b). Nine subjects were enrolled at two dose levels. The first three subjects had very high pleural and systemic IFN-α concentrations resulting in severe "flu-like" symptoms necessitating dose de-escalation. The next six patients had reduced (but still significant) pleural and serum IFN-α levels, but with tolerable symptoms. Repeated vector administration appeared to prolong IFN-α expression levels. Anti-tumor humoral immune responses against mesothelioma cell lines were seen in seven of the eight subjects evaluated. No clinical responses were seen in the four subjects with advanced disease. However, evidence of disease stability or tumor regression was seen in the remaining five patients, including one dramatic example of partial tumor regression at sites not in contiguity with vector infusion. These data show that Ad.IFN-α2b has potential therapeutic benefit in MPM and that it generates anti-tumor immune responses that may induce anatomic and/or metabolic reductions in distant tumor. Clinical trial registered with www.clinicaltrials.gov (NCT 01212367).

Increased efficacy of doxorubicin delivered in multifunctional microparticles for mesothelioma therapy

New and effective treatment strategies are desperately needed for malignant mesothelioma (MM), an aggressive cancer with a poor prognosis. We have shown previously that acid-prepared mesoporous microspheres (APMS) are nontoxic after intrapleural or intraperitoneal (IP) administration to rodents. The purpose here was to evaluate the utility of APMS in delivering chemotherapeutic drugs to human MM cells in vitro and in two mouse xenograft models of MM. Uptake and release of doxorubicin (DOX) alone or loaded in APMS (APMS-DOX) were evaluated in MM cells. MM cell death and gene expression linked to DNA damage/repair were also measured in vitro. In two severe combined immunodeficient mouse xenograft models, mice received saline, APMS, DOX or APMS-DOX injected directly into subcutaneous (SC) MM tumors or injected IP after development of human MMs peritoneally. Other mice received DOX intravenously (IV) via tail vein injections. In comparison to DOX alone, APMS-DOX enhanced intracellular uptake of DOX, MM death and expression of GADD34 and TP73. In the SC MM model, 3× weekly SC injections of APMS-DOX or DOX alone significantly inhibited tumor volumes, and systemic DOX administration was lethal. In mice developing IP MMs, significant (p < 0.05) inhibition of mesenteric tumor numbers, weight and volume was achieved using IP administration of APMS-DOX at one-third the DOX concentration required after IP injections of DOX alone. These results suggest APMS are efficacious for the localized delivery of lower effective DOX concentrations in MM and represent a novel means of treating intracavitary tumors.

Vesicular stomatitis virus-induced immune suppressor cells generate antagonism between intratumoral oncolytic virus and cyclophosphamide

Despite having potent oncolytic activity, in vitro, direct intratumoral injection of oncolytic vesicular stomatitis virus (VSV) into established AE17ova mesothelioma tumors in C57Bl/6 mice had no therapeutic effect. During studies to combine systemic cyclophosphamide (CPA) with VSV to suppress the innate immune reaction against VSV, we observed that CPA alone had highly significant antitumor effects in this model. However, against our expectations, the combination of CPA and VSV consistently reduced therapeutic efficacy compared to CPA alone, despite the fact that the combination increased intratumoral VSV titers. We show here that CPA-mediated therapy against AE17ova tumors was immune-mediated and dependent upon both CD4 T cells and natural killer (NK) cells. However, intratumoral VSV induced a transforming growth factor-β (TGF-β)-dependent suppressive activity, mediated by CD11b(+)GR-1(+) cells that significantly inhibited both antigen-specific T-cell activation, and CPA-activated, NK-dependent killing of AE17ova tumor cells. Overall, our results show that treatment with oncolytic viruses can induce a variety of immune-mediated consequences in vivo with both positive, or negative, effects on antitumor therapy. These underexplored immune consequences of treatment with oncolytic viruses may have significant, and possibly unexpected, impacts on how virotherapy interacts in combination with other agents which modulate antitumor immune effectors.

Management of malignant pleural mesothelioma

Malignant pleural mesothelioma is a rare neoplasm arising from the surface serosal cells of the pleural cavity. More than 80% of cases of malignant pleural mesothelioma have been attributed to asbestos exposure. In its natural course median survival is 4 to 12 months. If untreated most of patients die due to local complications of the disease. Surgery improves local control but is not sufficient as a single treatment modality. The recommended treatment strategy for a select group of patients is multimodal therapy that includes surgery, radiotherapy and chemotherapy.

Evaluation of an attenuated vesicular stomatitis virus vector expressing interferon-beta for use in malignant pleural mesothelioma: heterogeneity in interferon responsiveness defines potential efficacy

Abstract Vesicular stomatitis virus (VSV) has shown promise as an oncolytic agent, although unmodified VSV can be neurotoxic. To avoid toxicity, a vector was created by introducing the interferon-beta (IFN-beta) gene (VSV.IFN-beta). We conducted this study to determine the ability of VSV.IFN-beta to lyse human cancer (mesothelioma) cells and to evaluate the potential of this recombinant virus for clinical translation. Four normal human mesothelial and 12 mesothelioma cell lines were tested for their susceptibility to VSV vectors in vitro. VSV.hIFN-beta did not cause cytotoxicity in any normal lines. Only 4 of 12 lines were effectively lysed by VSV.hIFN-beta. In the eight resistant lines, pretreatment with IFN-beta prevented lysis of cells by VSV.GFP, and VSV infection or addition of IFN-beta protein resulted in the upregulation of double-stranded RNA-dependent protein kinase (PKR), myxovirus resistance A (MxA), and 2',5'-oligo-adenylate-synthetase (2'5'-OAS) mRNA. In the susceptible lines, there was no protection by pretreatment with IFN-beta protein and no IFN- or VSV-induced changes in PKR, MxA, and 2'5'-OAS mRNA. This complete lack of IFN responsiveness could be explained by marked downregulation of interferon alpha receptors (IFNARs), p48, and PKR in both the mesothelioma cell lines and primary tumor biopsies screened. Presence of p48 in three tumor samples predicted responsiveness to IFN. Our data indicate that many mesothelioma tumors have partially intact IFN pathways that may affect the efficacy of oncolytic virotherapy. However, it may be feasible to prescreen individual susceptibility to VSV.IFN-beta by immunostaining for the presence of p48 protein.

Expression of IFN-beta enhances both efficacy and safety of oncolytic vesicular stomatitis virus for therapy of mesothelioma

Our preclinical and clinical trials using a replication-defective adenoviral vector expressing IFN-beta have shown promising results for the treatment of malignant mesothelioma. Based on the hypotheses that a replication-competent vesicular stomatitis virus (VSV) oncolytic vector would transduce more tumor cells in vivo, that coexpression of the immunostimulatory IFN-beta gene would enhance the immune-based effector mechanisms associated both with regression of mesotheliomas and with VSV-mediated virotherapy, and that virus-derived IFN-beta would add further safety to the VSV platform, we tested the use of IFN-beta as a therapeutic transgene expressed from VSV as a novel treatment for mesothelioma. VSV-IFN-beta showed significant therapy against AB12 murine mesotheliomas in the context of both local and locoregional viral delivery. Biologically active IFN-beta expressed from VSV added significantly to therapy compared with VSV alone, dependent in part on host CD8+ T-cell responses. Immune monitoring suggested that these antitumor T-cell responses may be due to a generalized T-cell activation rather than the priming of tumor antigen-specific T-cell responses. Finally, IFN-beta also added considerable extra safety to the virus by providing protection from off-target viral replication in nontumor tissues and protected severe combined immunodeficient mice from developing lethal neurotoxicity. The enhanced therapeutic index provided by the addition of IFN-beta to VSV therefore provides a powerful justification for the development of this virus for future clinical trials.

A prognostic index for progression-free survival in malignant mesothelioma with application to the design of phase II trials: a combined analysis of 10 EORTC trials

PURPOSE

For cytostatic agents or when the response assessment is difficult, adaptations to phase II designs may allow a better assessment of therapeutic activity: first by using the progression-free survival rate (PFSR) as primary end-point instead of the response rate, and second by considering progression-free survival (PFS) risk groups based on a prognostic index (PI). In mesothelioma, current treatments yield disappointingly poor results and there is a need to investigate new regimens. The purpose of this report is to provide a PI for PFS in mesothelioma and reference values for the PFSR.

MATERIALS AND METHODS

Data on 523 patients included in 10 European Organisation for Research and Treatment of Cancer (EORTC) mesothelioma studies were analysed to identify prognostic factors using a multivariate Cox regression model. Subsequently, a PI and a nomogram for PFS were developed. The PFSRs at 3, 4, 5 and 6 months were estimated.

RESULTS

A performance status>0, stage IV disease and mixed or sarcomatous histological type were indicators of a poor prognosis for PFS. From the PI, based on these three variables, four risk groups were defined. The median progression-free survival ranged from 5.3 to 2.1 months in these risk categories. The PFSRs at 3 months were 70.6%, 62.4%, 54.2% and 42.1% in the four categories, respectively.

CONCLUSION

The PI allows dividing patients into homogeneous risk categories in which PFSRs can be calculated and used to design future phase II mesothelioma trials. Defining homogeneous categories of patients avoids dilution of results between groups and improves the assessment of therapeutic activity.

[Radiologic manifestation of primary pleural tumors]

OBJECTIVES

To show the radiological manifestations of primary pleural tumors.

PATIENTS AND METHODS

we carried out a retrospective analysis of radiological findings in 62 patients with primary malignant tumor of pleura.

RESULTS

Study included 39 male and 23 female patients. Malignant tumors were present in 92.7% of the patients and benign ones in 7.2%. The most common malignant tumor was mesothelioma (85.4%), and solitary fibrous tumor prevailed among benign tumors (9.7%). Diffuse malignant mesothelioma manifested on computed tomography (CT) as a pleural thickening and effusion in 67.4% of the patients, tumors and effusion in 11.7%, and only as an effusion in 9.8% cases. Thickening of the pleura appeared diffuse in 54% of patients and most often it had nodular pattern. Both localized malignant and all benign tumors presented as tumor-like changes with the signs of necrosis in 50%.

CONCLUSION

The imaging methods have a key role in the diagnosis of pleural tumors. CT shows different morphologic features of pleural lesions that have been established as a useful tool for differentiating malignant from benign disease. However, magnetic resonance is preferred imaging method for assessing the extent and resectability of pleural tumors.

Diagnostic value of carcinoembryonic antigen in malignant pleural effusion: a meta-analysis

BACKGROUND AND OBJECTIVE

Conventional tests are not always helpful in making a diagnosis of malignant pleural effusion (MPE). Many studies have investigated the utility of pleural carcinoembryonic antigen (CEA) in the early diagnosis of MPE. The present meta-analysis determined the accuracy of CEA measurement in the diagnosis of MPE.

METHODS

A systematic review of English language studies was conducted and data on the accuracy of pleural CEA concentrations in the diagnosis of MPE were pooled using random effects models. Receiver operating characteristic curves were used to summarize the overall test performance.

RESULTS

Forty-five studies met the inclusion criteria for the meta-analysis. The summary estimates for CEA in the diagnosis of MPE were: sensitivity 0.54 (95% CI: 0.52-0.55), specificity 0.94 (95% CI: 0.93-0.95), positive likelihood ratio 9.52 (95% CI: 6.97-13.01), negative likelihood ratio 0.49 (95% CI: 0.44-0.54) and diagnostic odds ratio 22.5 (95% CI: 15.6-32.5). Analysis of a subset of 11 studies which examined the value of pleural CEA in ruling out a diagnosis of malignant mesothelioma found that the sensitivity and specificity of a CEA level exceeding cut-off values were 0.97 (95% CI: 0.93-0.99) and 0.60 (95% CI: 0.55-0.65), respectively.

CONCLUSIONS

Measurement of pleural CEA is likely to be a useful diagnostic tool for confirming MPE, and is also helpful in the differential diagnosis between malignant pleural mesothelioma and metastatic lung cancer. The results of CEA assays should be interpreted in parallel with clinical findings and the results of conventional tests.

Malignant peritoneal mesothelioma as a rare cause of ascites: a case report

Introduction

Peritoneal mesothelioma is a rare tumor with diagnostic and therapeutic problems. The peritoneum is the second most common site for development of mesothelioma, which in 30–45% of cases is associated with a synchronous pleural mesothelioma. Clinical symptoms and findings may be confusing and diagnosis can be easily overlooked especially in cases where there is no previous asbestos exposure.

Case presentation

We report a case of malignant peritoneal mesothelioma in a 75-year-old woman who presented with ascites which, in the absence of inhalational exposure to asbestos, caused diagnostic confusion, and evaded radiological detection.

Conclusion

We concluded from this case that Peritoneal Mesothelioma although rare but should be considered among the differential diagnosis of Ascites.

Evaluating target coverage and normal tissue sparing in the adjuvant radiotherapy of malignant pleural mesothelioma: helical tomotherapy compared with step-and-shoot IMRT

PURPOSE

To evaluate the potential of helical tomotherapy in the adjuvant treatment of malignant pleural mesothelioma and compare target homogeneity, conformity and normal tissue dose with step-and-shoot intensity-modulated radiotherapy.

METHODS AND MATERIALS

Ten patients with malignant pleural mesothelioma who had undergone neoadjuvant chemotherapy with cisplatin and permetrexed followed by extrapleural pneumonectomy (EPP) were treated in our department with 54 Gy to the hemithorax delivered by step-and-shoot IMRT. A planning comparison was performed by creating radiation plans for helical tomotherapy. The different plans were compared by analysing target homogeneity using the homogeneity indices HI(max) and HI(min) and target conformity by using the conformity index CI(95). To assess target coverage and normal tissue sparing TV(90), TV(95) and mean and maximum doses were compared.

RESULTS

Both modalities achieved excellent dose distributions while sparing organs at risk. Target coverage and homogeneity could be increased significantly with helical tomotherapy compared with step-and-shoot IMRT. Mean dose to the contralateral lung could be lowered beyond 5 Gy.

CONCLUSIONS

Our planning study showed that helical tomotherapy is an excellent option for the adjuvant intensity-modulated radiotherapy of MPM. It is capable of improving target coverage and homogeneity.