A proposed new international TNM staging system for malignant pleural mesothelioma. From the International Mesothelioma Interest Group

CD26 overexpression is associated with prolonged survival and enhanced chemosensitivity in malignant pleural mesothelioma

PURPOSE

Malignant pleural mesothelioma (MPM) is an aggressive and therapy-resistant neoplasm arising from the pleural mesothelial cells, without established indicators to predict responsiveness to chemotherapy.

EXPERIMENTAL DESIGN

Our study involving 79 MPM patients showed that 73.4% of MPM expressed CD26 on cell membrane.

RESULTS

The majority of epithelioid and biphasic types of MPM expressed CD26 on the cell membrane, whereas the sarcomatoid type showed a lack of CD26 surface expression. Although the sarcomatoid type was associated with poor prognosis (P < 0.0001), no significant relationship between CD26 expression and survival was observed. On the contrary, there was a trend for an association between response rate to chemotherapy and CD26 expression (P = 0.053), with a higher level of CD26 expression more likely to be linked to better response to chemotherapy. Moreover, CD26 expression was a significant factor associated with improved survival in patients who received chemotherapy [median survival time (MST), 18.6 vs. 10.7 months, P = 0.0083]. Furthermore, CD26 expression was significantly associated with better prognosis in patients receiving non-pemetrexed-containing regimens (MST, 14.2 vs. 7.4 months, P = 0.0042), whereas there was no significant association between CD26 expression and survival time for patients receiving pemetrexed-containing regimens. Our in vitro and microarray studies showed that mesothelioma cells expressing high CD26 displayed high proliferative activity, and CD26 expression was closely linked to cell-cycle regulation, apoptosis, and chemotherapy resistance.

CONCLUSIONS

Our results strongly suggest that CD26 is a clinically significant biomarker for predicting response to chemotherapy for MPM.

Pathological and molecular biological approaches to early mesothelioma

Malignant mesothelioma is an asbestos-related malignancy that arises primarily from mesothelial cells on the serosal surfaces of the pleural, peritoneal, and pericardial cavities. Malignant pleural mesothelioma (MPM) is most common, and its incidence is dramatically increasing worldwide as a result of widespread use of asbestos. Morphological discrimination between MPM and reactive mesothelial hyperplasia is difficult, and the most reliable pathological criterion for malignancy is mesothelial proliferation invading deeply into subpleural adipose tissues. To establish radical cure of MPM, it is crucial to find early-stage MPM of epithelial type, in which mesothelial proliferation is localized on the serosal surface of parietal pleura or limited within the submesothelial fibrous tissues of parietal pleura. The initial clinical presentation for patients with MPM is frequently dyspnea and/or chest pain due to large pleural effusion, and cytological analysis of pleural effusions is valuable to find patients with early-stage MPM of epithelial type. Recently, cytological features of MPM in pleural effusion, molecular markers for MPM, and genetic alternations of MPM have been reported. In this review, we discuss major issues on pathological and molecular biological approaches for diagnosis of early-stage MPM of epithelial type.

National survey of malignant mesothelioma and asbestos exposure in Japan

In the present study, malignant mesothelioma (MM) cases in Japan were investigated retrospectively. We extracted records for 6030 cases of death due to MM between 2003 and 2008 to clarify the clinical features of MM, including its association with asbestos exposure (AE). Of all these cases, a clinical diagnosis of MM was confirmed for 929. The origin of MM included the pleura in 794 cases (85.5%), the peritoneum in 123 cases (13.2%), the pericardium in seven cases (0.8%), and the testicular tunica vaginalis in five cases (0.5%). The histological subtypes of MM included 396 epithelioid (55.9%), 154 sarcomatoid (21.7%), 126 biphasic (17.8%), and 33 cases (4.7%) classified as "other types". Of all the MM cases, AE was indicated in 76.8% and pleural plaques were detected in 34.2%. The number of asbestos particles was determined in 103 cases of MM. More than 1000 asbestos particles per gram dried lung tissue were detected in 74.8% of cases and more than 5000 particles were detected in 43.7% of cases. We compared patient characteristics and the diagnostic procedures for MM before and after the "Kubota shock". Compared with the early phase of this study (2003-2005), the median age at diagnosis of MM was higher, the number of cases without definite diagnosis of MM was lower, the proportion of cases diagnosed by thoracoscopy was higher, and the percentage of cases in which the occupational history was described in the medical records was significantly higher in the later phase (2006-2008). Our study confirmed that more than 70% of MM cases in Japan are associated with AE. The "Kubota shock" may affect some features pertaining to MM.

Clinical role of pleural effusion MMP-3 levels in malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is an aggressive malignant tumor of mesothelial origin associated with asbestos exposure. MPM exhibits a limited response to conventional chemotherapy and radiotherapy. This, early diagnosis of MPM is essential. Malignant tumor progression requires the destruction of the basement membrane, which is constructed from extracellular matrix (ECM) materials. Various types of human tumor cells are reported to produce ECM-degrading proteases that are important in tumor progression. Among this group of proteolytic enzymes, matrix metalloproteinases (MMPs) are thought to be important due to their wide degrading function. We investigated the pleural effusion MMP-3 levels of patients with MPM and compared them with those of a population with non-malignant pleuritis or lung cancer involving malignant pleural effusion. The pleural effusion MMP-3 concentrations of 52 MPM patients and 67 non-MPM patients were measured. The results showed that the MPM patients had significantly higher pleural effusion MMP-3 levels than the population with non-malignant pleuritis. The overall survival of the MPM patients with lower pleural effusion MMP-3 levels was longer than that of patients with higher pleural effusion MMP-3 levels. Our data therefore suggest a clinical role of pleural effusion MMP-3 levels in malignant pleural mesothelioma.

Clinical impact of extrapleural pneumonectomy for malignant pleural mesothelioma

BACKGROUND

The clinical impact of extrapleural pneumonectomy in malignant pleural mesothelioma is poorly investigated.

METHODS

Between 1997 and 2007, 29 consecutive patients underwent extrapleural pneumonectomy for mesothelioma and adjuvant chemoradiotherapy. Function (spirometry, arterial blood gas analysis, 6-min walk test, and echocardiographic fraction ejection estimation), symptoms (quantification of pain, dyspnea, cough, fever, weight loss, and Karnofsky performance status) and quality of life [Medical Outcomes Study Short Form, 36 item (SF-36) and St. George's Respiratory Questionnaire] were timely evaluated. Data were prospectively collected and retrospectively reviewed.

RESULTS

Only one postoperative death occurred. 30-day postoperative morbidity was 41%. Median survival was 19.5 months with 17 patients still alive at 1 year and 10 at 2 years, respectively. At 3 months, the expected decrement of forced expiratory volume in 1 s (P = 0.06) and forced vital capacity (P = 0.09) was not significant. Conversely, arterial blood gas, 6-min walk test, cardiac fraction ejection, pain (P < 0.05), dyspnea (P < 0.01), cough (P < 0.05), fever (P < 0.01), weight loss (P < 0.01), performance status (P < 0.01), SF-36 physical (P < 0.01), SF-36 mental (P < 0.05), St. George's Respiratory Questionnaire symptom (P < 0.01), activity (P < 0.05), and impact on mood (P < 0.05) improved. At 12 months, the amelioration of pain, dyspnea, performance status, and physical-related quality of life parameters remained stable. Thereafter, all parameters progressively deteriorated, although pain and dyspnea still persisted above the baseline values even after 24 months in all survivors. Postoperative improvement of pain (P = 0.04), dyspnea (P = 0.04), 6-min walk test (P = 0.03), and SF-36 physical (P = 0.04) and mental (P = 0.03) components were positive prognosticators.

CONCLUSIONS

Extrapleural pneumonectomy has a significant and durable impact on function and symptoms as well as on physical and mental components of quality of life in patients with malignant pleural mesothelioma.

A case of diffused malignant pleural mesothelioma forming small multiple disseminations with intraoperatively suspicious carcinoid tumors

A 65-year-old male, having symptoms suggestive of pulmonary malignant tumor, underwent video-assisted thoracic surgery (VATS). Surgery revealed a solid tumor originating from the thoracic wall, with many small solid tumors in the thoracic wall and diaphragm near the tumor. The intraoperative observation of a frozen section typed the tumor as carcinoid; however, hematoxylin-eosin staining and immunohistological findings provided the definitive diagnosis of diffused, malignant pleural mesothelioma (MPM).

Biomarkers in malignant mesothelioma: diagnostic and prognostic role of soluble mesothelin-related peptide

Soluble mesothelin-related peptide (SMRP) is a biomarker that has been proposed for differential diagnosis from pleural metastatic cancer, as well as prognosis and treatment monitoring of malignant pleural mesothelioma (MM). The aim of this study was to evaluate the role of SMRP in clinic management of MM. We assayed the SMRP concentrations in 354 subjects: 109 healthy volunteers with no history of exposure to asbestos, 26 patients with previous occupational asbestos exposure but who were free from pleural or parenchymal disease, 48 patients with asbestosis, 110 patients with pleural plaques, 25 patients with lung cancer, and 36 patients with MM. We also tested SMRP titers in 2 patients with MM at 5 different times of the disease, to evaluate the trend of the biomarker in the course of therapy. Our data confirm previous experiences with the use of SMRP as a diagnostic marker of MM. Low SMRP levels at diagnosis seem to have a positive prognostic significance.

[Pleural mesothelioma: where are we with radical surgery and multimodal treatment?]

Multimodal treatment of pleural mesothelioma, which is reserved for specialised centres for epithelial forms without node involvement, must include preliminary laparoscopy, thoracoscopy and mediastinoscopy. Following chemotherapy, in our opinion surgical removal via pleuropneumonectomy should be performed without resection of the diaphragm and the pericardium, because of the risks of seeding and postoperative complications. Our limited experience with 15 patients has confirmed the feasibility of this with no deaths. High-dose radiotherapy of the whole pneumonectomy cavity appears essential, but the optimal technique is debatable. Only five homogeneous series of more than 40 patients incorporating hemithoracic radiotherapy have been published.

Is serum thioredoxin-1 a useful clinical marker for malignant pleural mesothelioma?

Malignant pleural mesothelioma (MPM), an asbestos-related aggressive malignant tumor of mesothelial origin, shows limited response to therapy and overall survival remains very poor. Reactive oxygen species play an important role in asbestos toxicity. Here, we found that the patients with MPM had significantly higher serum levels of thioredoxin-1 (TRX) than control population. The patients with advanced-stage MPM showed higher levels of TRX than those with early-stage MPM. The difference in overall survival between the groups with lower and higher serum TRX levels was significant. Our data suggest that serum TRX concentration could be a useful clinical marker for MPM.

A 26-year-old male with mesothelioma due to asbestos exposure

Mesothelioma is a malignancy with poor prognosis, with an average 5-year survival rate being less than 9%. This type of cancer is almost exclusively caused by exposure to asbestos. A long exposure can cause mesothelioma and so can short ones, as each exposure is cumulative. We report a case of a 26-year-old male who was exposed to asbestos during his primary school years from the age of 6 to 12. Although the tumor mainly affects older men who in their youth were occupationally exposed to asbestos, malignant mesothelioma can also occur in young adults. A medical history was carefully taken and asbestos exposure was immediately mentioned by the patient. We conducted biopsy on the right supraclavicular lymph node. The patient was not a candidate for surgery, and chemotherapy treatment was initiated. While patient's chemotherapy is still ongoing, no other similar cases of students or teachers have been traced up to date from his school. The school building was demolished in January 2009.

Extra-pleural pneumonectomy versus no extra-pleural pneumonectomy for patients with malignant pleural mesothelioma: clinical outcomes of the Mesothelioma and Radical Surgery (MARS) randomised feasibility study

BACKGROUND

The effects of extra-pleural pneumonectomy (EPP) on survival and quality of life in patients with malignant pleural mesothelioma have, to our knowledge, not been assessed in a randomised trial. We aimed to assess the clinical outcomes of patients who were randomly assigned to EPP or no EPP in the context of trimodal therapy in the Mesothelioma and Radical Surgery (MARS) feasibility study.

METHODS

MARS was a multicentre randomised controlled trial in 12 UK hospitals. Patients aged 18 years or older who had pathologically confirmed mesothelioma and were deemed fit enough to undergo trimodal therapy were included. In a prerandomisation registration phase, all patients underwent induction platinum-based chemotherapy followed by clinical review. After further consent, patients were randomly assigned (1:1) to EPP followed by postoperative hemithorax irradiation or to no EPP. Randomisation was done centrally with computer-generated permuted blocks stratified by surgical centre. The main endpoints were feasibility of randomly assigning 50 patients in 1 year (results detailed in another report), proportion randomised who received treatment, proportion eligible (registered) who proceeded to randomisation, perioperative mortality, and quality of life. Patients and investigators were not masked to treatment allocation. This is the principal report of the MARS study; all patients have been recruited. Analyses were by intention to treat. This trial is registered, number ISRCTN95583524.

FINDINGS

Between Oct 1, 2005, and Nov 3, 2008, 112 patients were registered and 50 were subsequently randomly assigned: 24 to EPP and 26 to no EPP. The main reasons for not proceeding to randomisation were disease progression (33 patients), inoperability (five patients), and patient choice (19 patients). EPP was completed satisfactorily in 16 of 24 patients assigned to EPP; in five patients EPP was not started and in three patients it was abandoned. Two patients in the EPP group died within 30 days and a further patient died without leaving hospital. One patient in the no EPP group died perioperatively after receiving EPP off trial in a non-MARS centre. The hazard ratio [HR] for overall survival between the EPP and no EPP groups was 1·90 (95% CI 0·92-3·93; exact p=0·082), and after adjustment for sex, histological subtype, stage, and age at randomisation the HR was 2·75 (1·21-6·26; p=0·016). Median survival was 14·4 months (5·3-18·7) for the EPP group and 19·5 months (13·4 to time not yet reached) for the no EPP group. Of the 49 randomly assigned patients who consented to quality of life assessment (EPP n=23; no EPP n=26), 12 patients in the EPP group and 19 in the no EPP group completed the quality of life questionnaires. Although median quality of life scores were lower in the EPP group than the no EPP group, no significant differences between groups were reported in the quality of life analyses. There were ten serious adverse events reported in the EPP group and two in the no EPP group.

INTERPRETATION

In view of the high morbidity associated with EPP in this trial and in other non-randomised studies a larger study is not feasible. These data, although limited, suggest that radical surgery in the form of EPP within trimodal therapy offers no benefit and possibly harms patients.

FUNDING

Cancer Research UK (CRUK/04/003), the June Hancock Mesothelioma Research Fund, and Guy's and St Thomas' NHS Foundation Trust.

Thoracoscopic assessment of pleural tumor burden in patients with malignant pleural effusion: prognostic and therapeutic implications

BACKGROUND

Malignant pleural effusion (MPE) is encountered at an advanced stage of disease progression and often heralds a poor prognosis. The most reliable predictive factor of survival in such patients is the primary tumor. Thoracoscopy is often performed for accurate diagnosis and/or thoracoscopic talc insufflation as a therapeutic modality. It remains unknown whether pleural tumor burden, as visualized on thoracoscopy, has potential prognostic value. The objective of this study was to determine the prognostic accuracy of pleural tumor extent and localization (parietal, visceral, or diaphragmatic involvement), as assessed during medical thoracoscopy.

METHODS

Medical records of all patients who underwent thoracoscopy for suspicion of MPE between 2001 and 2008 at a tertiary care referral hospital were reviewed. Patients were included if pleural metastatic invasion was confirmed on tissue biopsy and survival status ascertained.

RESULTS

Four hundred twenty-one patients underwent diagnostic or therapeutic medical thoracoscopy at our referral center. Among them, 122 had confirmed metastatic pleural spread, but survival data were lacking in 15. Primary tumor consisted of non-mall cell lung cancer in 56, breast cancer in 23, melanoma in eight, and other malignancies in 20. Median survival of the entire population was 9.4 months. On univariate analysis, the following variables were significantly associated with reduced median overall survival: pleural metastatic melanoma, age less than 60 years, bloody MPE, extensive pleural adhesions, and widespread visceral pleural nodules (p < 0.05). On multivariate analysis, only melanoma as a primary tumor, pleural fluid appearance and extent of pleural adhesions remained independent and significant predictors of survival.

CONCLUSION

No significant association was found between the extent or localization of pleural tumor burden and overall survival.

Multimodality Imaging Review of Malignant Pleural Mesothelioma Diagnosis and Staging

Early diagnosis and accurate disease staging in patients with malignant pleural mesothelioma (MPM) are essential in classifying such patients into prognostic subgroups to allow delivery of stage-specific therapies. This review addresses the current status of multimodality imaging in the diagnosis and staging of MPM. Clinical, research, and future directions in computed tomography (CT), magnetic resonance imaging, and PET/CT diagnosis and staging of MPM are discussed, including the use of novel PET probes. The article concludes with important take-home messages summarized as the pearls and pitfalls of each diagnostic modality in the diagnosis and staging of patients with MPM.

Thrombomodulin is silenced in malignant mesothelioma by a poly(ADP-ribose) polymerase-1-mediated epigenetic mechanism

Malignant mesothelioma (MM) is often complicated by thromboembolic episodes, with thrombomodulin (TM) playing a critical role in the anticoagulant process. Heterogeneous expression of TM has been observed in cancer, and low or no TM expression in cancer cells is associated with poor prognosis. In this study, we analyzed TM expression in biopsies of MM patients and compared them with normal mesothelial tissue. The role of DNA methylation-associated gene silencing in TM expression was investigated. To evaluate poly(ADP-ribose) polymerase-1 (PARP1) as responsible for gene promoter epigenetic modifications, nonmalignant mesothelial cells (Met-5A) and MM cells (H28) were silenced for PARP1 and the DNA methylation/acetylation-associated TM expression evaluated. A correlation between low TM expression and high level of TM promoter methylation was found in MM biopsies. Low expression of TM was restored in MM cells by their treatment with 5-aza-2'-deoxycytidine and, to a lesser extent, with trichostatin, whereas the epigenetic agents did not affect TM expression in Met-5A cells. Silencing of PARP1 resulted in a strong down-regulation of TM expression in Met-5A cells, while restoring TM expression in H28 cells. PARP1 silencing induced TM promoter methylation in Met-5A cells and demethylation in MM cells, and this was paralleled by corresponding changes in the DNA methyltransferase activity. We propose that methylation of the TM promoter is responsible for silencing of TM expression in MM tissue, a process that is regulated by PARP1.

Summary of prognostic factors and patient selection for extrapleural pneumonectomy in the treatment of malignant pleural mesothelioma

BACKGROUND

Extrapleural pneumonectomy (EPP) has been shown to improve long-term survival outcomes in selected patients with malignant pleural mesothelioma (MPM). The present study aimed to evaluate potential prognostic factors on overall survival for patients who underwent EPP for MPM and to examine the patient selection process in major referral centers that perform EPP.

METHODS

A systematic review of the current literature was performed using 5 electronic databases. Relevant studies with prognostic data on overall survival for patients with MPM treated by EPP were included for review. Two reviewers independently assessed each included study.

RESULTS

A total of 17 studies from 13 institutions containing the most updated and complete data on prognostic factors for patients with MPM who underwent EPP were included for review. A number of quantitative, clinical, and treatment-related factors were identified to have significant impact on overall survival.

CONCLUSIONS

Patients with nonepithelial MPM and nodal involvement have consistently demonstrated to have a worse prognosis after EPP. Their eligibility as candidates for EPP should be questioned. The preoperative patient selection process currently differs greatly between institutions and should focus on identifying patients with nonepithelial histologic subtypes and nodal involvement to exclude them as EPP surgical candidates in the future.

Association of MiR-126 with soluble mesothelin-related peptides, a marker for malignant mesothelioma

Background

Improved detection methods for diagnosis of malignant pleural mesothelioma (MPM) are essential for early and reliable detection as well as treatment. Since recent data point to abnormal levels of microRNAs (miRNAs) in tumors, we hypothesized that a profile of deregulated miRNAs may be a marker of MPM and that the levels of specific miRNAs may be used for monitoring its progress.

Methods and Results

miRNAs isolated from fresh-frozen biopsies of MPM patients were tested for the expression of 88 types of miRNA involved in cancerogenesis. Most of the tested miRNAs were downregulated in the malignant tissues compared with the normal tissues. Of eight significantly downregulated, three miRNAs were assayed in cancerous tissue and adjacent non-cancerous tissue sample pairs collected from 27 formalin-fixed, paraffin-embedded MPM tissues by quantitative RT-PCR. Among the miRNAs tested, only miR-126 significantly remained downregulated in the malignant tissues. Furthermore, the performance of the selected miR-126 as biomarker was evaluated in serum samples of asbestos-exposed subjects and MPM patients and compared with controls. MiR-126 was not affected by asbestos exposure, whereas it was found strongly associated with VEGF serum levels. Levels of miR-126 in serum, and its levels in patients' serum in association with a specific marker of MPM, SMRPs, correlate with subjects at high risk to develop MPM.

Conclusions and Significance

We propose miR-126, in association with SMRPs, as a marker for early detection of MPM. The identification of tumor biomarkers used alone or, in particular, in combination could greatly facilitate the surveillance procedure for cohorts of subjects exposed to asbestos.

Expert opinions of the first italian consensus conference on the management of malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is a very important public health issue. A large amount of data indicates a relationship between mesothelioma and asbestos exposure. The incidence has both considerably and constantly increased over the past 2 decades in the industrialized countries and is expected to peak in 2010-2020. In Italy, a standardized-rate incidence in 2002 among men was 2.98 per 100,000 and 0.98 per 100,000 among women, with wide differences from one region to another. Stage diagnosis and definition may be difficult. Management of patients with MPM remains complex, so an optimal treatment strategy has not yet been clearly defined. The First Italian Consensus Conference on Malignant Pleural Mesothelioma was held Bologna (Italy) in May 20, 2008. The Consensus Conference was given the patronage of the Italian scientific societies AIOM, AIRO, AIPO, SIC, SICO, SICT, SIAPEC-IAP, AIOT, GOAM, and GIME. This Consensus did not answer all of the unresolved questions in MPM management, but the Expert Opinions have nonetheless provided recommendations, presented in this report, on MPM management for clinicians and patients.

Surgical therapy of mesothelioma

The treatment of malignant pleural mesothelioma is controversial, particularly regarding the role of surgery. Though well accepted as a diagnostic modality, surgery is also frequently used to establish stage, provide palliation, and perhaps most controversially, to offer cytoreduction with the putative goal of delaying tumor progression and prolonging survival. Pleurectomy/decortication (PD) can achieve macroscopic complete resection; however, the ability to deliver effective postoperative radiation treatment is limited because of the risk of lung toxicity. Accordingly, it has been associated with higher rates of local recurrence compared to extrapleural pneumonectomy (EPP). Extrapleural pneumonectomy generally offers a more complete cytoreduction compared to PD but at the cost of increased morbidity and mortality. Adjuvant hemithoracic radiation is feasible following EPP and in most series local recurrence rates are lower after EPP than PD. There are no convincing data, however, to show that one procedure is superior to the other in terms of survival. Furthermore, no randomized data currently exist that demonstrate a survival benefit to any form of surgical cytoreduction over systemic treatment and supportive care. If cytoreductive surgery does have a beneficial effect on long-term survival, it will most likely be realized in patients with epithelioid tumors without nodal metastases.

CD8+ tumor-infiltrating lymphocytes predict favorable prognosis in malignant pleural mesothelioma after resection

Defects in human leukocyte antigen (HLA) class I expression may allow tumor cells to escape immune recognition. T cell infiltration is associated with a good prognosis in many cancers. However, the role of HLA class I expression and tumor-infiltrating lymphocytes (TILs) in malignant pleural mesothelioma (MPM) has not been fully analyzed. In the present study, we investigated the immune profiles and conducted outcome analyses of MPM patients. HLA class I expression and TILs (CD4(+), CD8(+), and NK cells) were detected by immunohistochemistry in a series of 44 MPM cases. To detect HLA class I expression, specimens were stained with the anti-pan HLA class I monoclonal antibody EMR8-5. The expression of HLA class I was positive in all patients. There was no case that showed negative HLA class I expression. The density of CD4(+) and CD8(+) TILs were strongly correlated (R = 0.76, p < 0.001). A high density of CD8(+) TILs was a significantly better prognostic factor for the survival of patients with extrapleural pneumonectomy (p < 0.05). Multivariate analysis revealed that a high density of CD8(+) TILs is an independent prognostic factor for patients who underwent extrapleural pneumonectomy. The presence of intratumoral CD8(+) T cells was correlated with an improved clinical outcome, raising the possibility that CD8(+) T cells might play a pivotal role in the antitumor immune response against MPMs. Thus, the stimulation of CD8(+) lymphocytes might be an efficacious immunotherapy for MPM patients.

A₃ receptors are overexpressed in pleura from patients with mesothelioma and reduce cell growth via Akt/nuclear factor-κB pathway

RATIONALE

A strong link has been established between exposure to asbestos and increased risk for pleural malignant mesothelioma (MM). Adenosine plays a key role in inflammatory processes and cancer, where it is involved in the regulation of cell death and proliferation.

OBJECTIVES

The primary aim of this study was to investigate the presence of adenosine receptors (ARs) in human MM pleura (MMP) and healthy mesothelial pleura (HMP). To shed some light on the interaction between adenosine and MM, the presence and functionality of ARs were explored in human healthy mesothelial cells (HMC) and in malignant mesothelioma cells (MMC).

METHODS

ARs were analyzed by using reverse transcriptase-polymerase chain reaction, Western blotting, and saturation binding assays. HMC were treated with crocidolite asbestos, which is the principal risk factor for MM. The role of A₃ ARs on these cellular models, evaluating cAMP production, Akt phosphorylation, and nuclear factor (NF)-κB activation, was investigated. The dual effect of A₃AR stimulation on healthy and cancer cell growth was studied by means of proliferation, apoptosis, and cytotoxicity assays.

MEASUREMENTS AND MAIN RESULTS

A₃AR was up-regulated by 2.5-fold (P < 0.01) in MMP when compared with HMP. Stimulation of A₃ARs decreased proliferation and exerted a cytotoxic and proapoptotic effect on MMC and on HMC exposed to asbestos and tumor necrosis factor-α, but not on HMC with an involvement of the deregulation of Akt/NF-κB cell survival pathway.

CONCLUSIONS

These new findings suggest that A₃AR could represent a pharmacological target to prevent tumor development after asbestos exposure and to treat full-blown MM.

Successful salvage chemotherapy with gemcitabine and vinorelbine in a malignant pleural mesothelioma patient previously treated with pemetrexed

The role of second-line and salvage chemotherapy in malignant pleural mesothelioma treatment is not yet established. We report a case of relapsed malignant pleural mesothelioma in which the patient failed to respond to pemetrexed-based chemotherapy but was successfully treated with gemcitabine and vinorelbine. The patient underwent a left extrapleural pneumonectomy. Three years later she developed anterior chest wall and retroperitoneal masses. Histological findings revealed metastases from the malignant pleural mesothelioma. Although two cycles of carboplatin plus pemetrexed chemotherapy were administered, she had progressive disease. Then, 1000 mg/m(2) gemcitabine and 25 mg/m(2) vinorelbine were administered every 2 weeks. The chemotherapy regimen was tolerated well, and the tumors were remarkably reduced. She was treated with 12 cycles of gemcitabine plus vinorelbine, and 8.5 months of progression-free survival was observed. Gemcitabine plus vinorelbine chemotherapy may be a candidate regimen for salvage chemotherapy against malignant pleural mesotheliomas.

Intensity-Modulated Radiation Therapy with Simultaneous Integrated Boost in Unresected Left-Sided Pleural Mesothelioma: A Case Report

A 77-year-old male patient with unresected malignant pleural mesothelioma, clinical stage T3N0M0 according to the New International Staging System for Diffuse Malignant Pleural Mesothelioma, received intensity-modulated radiotherapy (IMRT) with a simultaneous integrated boost (SIB) after 6 cycles of chemotherapy with cisplatin and pemetrexed. SIB-IMRT delivered 40.5 Gy (1.5 Gy/fraction) to the left pleura and 50 Gy (1.85 Gy/fraction) to the sites of macroscopic disease. Radiotherapy was well tolerated. Two months after the end of radiotherapy the patient showed grade 2 lung toxicity (febrile episodes accompanied by dry cough) that was successfully treated with steroid therapy. Local control lasted for 2 years after SIB-IMRT. Then the tumor recurred marginally to the radiation field and the patient underwent chemotherapy with pemetrexed. Three years from the diagnosis, the patient is alive and in good general condition. He only takes prednisone 5 mg/daily for exertional dyspnea. To the best of our knowledge this is the first reported use of SIB-IMRT in unresected malignant pleural mesothelioma. Considering the dosimetric advantages of SIB-IMRT and the clinical results observed in our patient, additional evaluation of this technique seems justified.

Prognostic factors for 100 patients with malignant pleural mesothelioma

The aim of this study was to investigate the effects of various clinical, laboratory characteristics, and therapeutic modalities on the survival of patients with malignant pleural mesothelioma. One hundred consecutive patients with a pathologically proven diagnosis of malignant pleural mesothelioma treated between 1993 and 2005 were included in the study. Using a Cox proportional hazard model, comorbidity, weight loss, breathlessness, and performance status were identified as independent prognostic factors. Comorbidity had interestingly favorable effect on the survival. Treated patients with chemotherapy had significantly longer survival than those treated with best supportive care. However, it was necessary to complete at least 6 cycles for a survival benefit. In conclusions, comorbidity information should be recorded in the recent prognostic studies. The drugs used for the comorbidity may improve survival.

Carboplatin plus pemetrexed as first-line treatment of patients with malignant pleural mesothelioma: a phase II study

INTRODUCTION

Malignant pleural mesothelioma (MPM) is a rapidly progressive tumor that is increasing in frequency worldwide. Treatment options are limited, and response to chemotherapy is poor. The aim of this phase II study was to evaluate the activity of the carboplatin/pemetrexed combination as first-line chemotherapy in patients with unresectable MPM.

PATIENTS AND METHODS

Chemotherapy-naive patients with histologically confirmed MPM and an Eastern Cooperative Oncology Group performance status of 0-2 were enrolled. Treatment consisted of pemetrexed 500 mg/m2 and carboplatin area under the concentration-time curve of 5 mg/mL/min, both administered on day 1 of a 21-day cycle. The treatment continued until 6 cycles were completed or until unacceptable toxicity or disease progression were observed.

RESULTS

A total of 62 patients were enrolled. Of these patients, 18 (29%) had a confirmed partial response, whereas the disease remained stable in 34 patients (54.9%) and progressed in 10 patients (16.1%). The median overall survival (OS) was estimated at 14 months (95% CI, 11.8-16.2 months), and the median time to progression was 7 months (95% CI, 5.8-8.2 months). The difference in median OS between the epithelial histologic subtype (16 months) and the sarcomatoid subtype (11 months) was statistically significant.

CONCLUSION

This study confirmed the activity of the carboplatin/ pemetrexed combination in the first-line treatment of patients with MPM. It is a viable option, especially in cases in which side effects are generally anticipated.

Thymidylate Synthase But Not Excision Repair Cross-Complementation Group 1 Tumor Expression Predicts Outcome in Patients With Malignant Pleural Mesothelioma Treated With Pemetrexed-Based Chemotherapy

Purpose

The relationship between thymidylate synthase (TS) expression and outcome in patients with malignant pleural mesothelioma (MPM) treated with pemetrexed (P) was retrospectively evaluated.

Patients and Methods

Sixty histologically confirmed patients with MPM previously treated with P and platinum (45 of 60) or as single agent (15 of 60) were retrospectively considered. Eighty-one control patients with MPM not P-treated were also evaluated. TS and excision repair cross-complementation group 1 (ERCC1) gene expression levels were evaluated by real-time polymerase chain reaction and by immunohistochemistry using the H-score.

Results

Median TS H-score value was 90 (range, 5 to 240). A significant correlation between low TS protein expression and longer time to progression (TTP; 17.9 v 7.9 months; hazard ratio [HR], 2.05, 95% CI, 1.19 to 3.77; P = .02) or overall survival (OS; 30 v 16.7 months; HR, 2.38; 95% CI, 1.15 to 4.91; P = .019) was found when patients were divided according to median H-score. Conversely, TS mRNA levels were not significantly correlated with outcome. In platinum-treated patients (n = 45), no correlation was found with survival according to ERCC1 median H-score, but patients in the lower tertile had a significantly shorter survival (HR, 3.06; 95% CI, 1.08 to 8.69; P = .035). In control MPMs, TS had no prognostic role. At multivariate analysis, TS protein levels were the only independent prognostic factor for both TTP (HR, 2.71; 95% CI, 1.13 to 6.49; P = .02) and OS (HR, 6.91; 95% CI, 1.90 to 25.07; P = .003).

Conclusion

In patients with MPM treated with P-based chemotherapy, low TS protein levels are predictive of improved TTP and OS. The role of TS assessment is worth of prospective validation in future studies on MPM.

Effect of induction chemotherapy on lung function and exercise capacity in patients affected by malignant pleural mesothelioma

OBJECTIVES

The effect of induction chemotherapy (IC) on lung function and exercise capacity in patients with malignant pleural mesothelioma (MPM) has not been largely examined. The aim of this study was to evaluate the changes in pulmonary function and oxygen consumption following IC in patients with MPM.

METHODS

Between 2004 and 2009, 36 consecutive patients (mean age 62.1 + or - 1.5 years, M/F = 25/11) were prospectively investigated. Data concerning medical history, histology, staging and response to chemotherapy were collected. All patients underwent pulmonary function test before (in the absence of pleural effusion) and after chemotherapy (platinum-based agent plus pemetrexed); 23 out of 36 patients also performed a cardiopulmonary incremental exercise test.

RESULTS

An epithelioid histotype was documented in 88.8% of patients. A partial response to chemotherapy was observed in 44.5% of cases and 36.1% of patients experienced grade 2-3 toxicity. A significant improvement in forced expiratory volume in 1s (FEV(1)) (0.13 + or - 0.30 l; P = 0.01), in VO(2) peak (1.76 + or - 2.91 ml kg(-1) min(-1); P = 0.005), in PaO(2) at rest (4.76 + or - 9.84 mmHg; P = 0.03) and in PaO(2) at peak exercise (6.26 + or - 12.72 mmHg; P = 0.04) was detected. The diffusion capacity of the lung for carbon monoxide (DLCO) also increased (1.25 + or - 4.68 ml min(-1) mmHg(-1)), although not significantly (P = 0.20). The stratified analysis based on the response to IC showed a significant improvement in FEV(1), forced vital capacity (FVC) and vital capacity (VC) (both absolute and percentage of predicted values) only in patients with a partial response.

CONCLUSIONS

An improvement in lung function and exercise capacity was seen after IC in patients with MPM. These data suggest that IC does not compromise cardiopulmonary performance in this subset of patients.

Surgical assessment of malignant pleural mesothelioma: have we reached a critical stage?

OBJECTIVE

The International Mesothelioma Interest Group (IMIG) classification is the most widely used staging system but is based on post-resectional parameters. We aimed to test the association between clinical and pathological staging and to identify possible discrepancies.

METHODS

We identified 164 consecutive patients (144 males and 20 females, with mean age 58 years) who underwent radical surgery (114 extrapleural pneumonectomy; 50 radical pleurectomy/decortication) for malignant pleural mesothelioma (MPM). The patients were clinically staged with CT + or - MRI (CT, computed tomography; MRI, magnetic resonance imaging).

RESULTS

Clinical T (cT) stage proved to be the same as pathological T (pT) stage in 44%; understaged in 46% and overstaged in 10%. Clinical N (cN) stage proved to be the same as pathological N (pN) stage in 56%; understaged in 31% and overstaged in 13%. Disease-free interval (DFI) was associated with cT stage (median DFI 29 months, SE 13, 95% CI 3-54 months for cT1; median 5, SE 3, 95% CI 3-6 months for cT4, p=0.02) but not clinical N stage (median DFI 12 months, SE 1, 95% CI 9-15 months for cN0; median DFI 11 months, SE 0.3, 95% CI 10-12 months for cN2, p=0.5) and was associated with both pT (median DFI 31 months, SE 17, 95% CI 0-64 months for pT1; median DFI 8 months, SE1, 95% CI 6-11 months for pT4, p=0.03) and pN stage (median DFI 14 months, SE 3, 95% CI 9-20 months for pN0; median DFI 10 months, SE 1, 95% CI 8-13 months for pN2, p=0.02). Overall survival was associated with cT stage (median survival 25 months, SE 3, 95% CI 20-30 months for cT1; median survival 11 months, SE 3, 95% CI 10-11 months for cT4, p=0.01) but not cN stage (median survival 15 months, SE 2, 95% CI 11-19 months for cN0; median survival 15 months, SE 2, 95% CI 12-19 months for cN2, p=0.49) and pN stage (median survival 22 months, SE 3, 95% CI 19-27 months for pN0; median survival 14 months, SE 1, 95% CI 12-17 months for pN2, p=0.01) but not pT stage (median survival 27 months, SE 4, 95% CI 19-35 months for pT1; median survival 12 months, SE 2, 95% CI 9-15 months for pT4, p=0.06). Pathological IMIG stage was associated with DFI and overall survival; however, preoperative IMIG stage was less useful.

CONCLUSIONS

There are deficiencies in the current staging system for MPM and discrepancies between clinical and pathological systems. Future improvements are needed in clinical descriptors of nodal status and pathological descriptors of T stage. Subsequent IMIG stage grouping also needs revision.

Malignant mesothelioma

INTRODUCTION

Mesothelioma is a malignant tumour of the pleura or peritoneum caused by asbestos. It is increasing in frequency and the prognosis remains grim, with average survival around 1 year.

SOURCES OF DATA

Medical literature and personal experience.

AREAS OF AGREEMENT

Amphibole fibres are far more potent than chrysotile in causing mesothelioma.

AREAS OF CONTROVERSY

A minority view suggests that mesotheliomas in those exposed to chrysotile are caused only by tremolite (an amphibole) which contaminates chrysotile. There is a hypothesis, for which evidence is weakening, that Simian virus 40 may cause mesothelioma.

GROWING POINTS

There is emerging evidence of genetic variation in susceptibility to fibre carcinogenesis. There are developments in treatment, particularly chemotherapy with pemetrexed and cisplatin which prolongs survival and helps symptoms.

AREAS TIMELY FOR DEVELOPING RESEARCH

Targeted agents for treatment are under investigation and may improve the outlook. The role of radical and palliative surgery requires clarification.

Treatment with interleukin-2 in malignant pleural mesothelioma: immunological and angiogenetic assessment and prognostic impact

Background:

Administration of interleukin-2 (IL-2) has shown some effects on malignant pleural mesothelioma (MPM) tumour regression. The purpose of this study was to investigate the ability of IL-2 to modify immunological effector cells and angiogenesis in MPM patients and their prognostic value.

Methods:

Tumour-infiltrating lymphocytes (CD4, CD8, Foxp3), mast cells (MCs) (tryptase and chymase), microvessel count (MVC) and VEGF were determined by immunohistochemistry in two series of MPM patients: 60 patients treated with intra-pleural preoperative IL-2 and 33 patients untreated.

Results:

Tryptase MCs, and CD8 and Foxp3 lymphocytes were significantly increased in the IL-2-treated group, whereas MVC was significantly lower in the same group. Moreover, in the IL-2-treated group, greater tryptase+MCs and greater Foxp3 lymphocytes were associated with improved and poorer clinical outcomes, respectively. Notably, when these two immunological parameters were combined, they predicted outcomes more effectively.

Conclusions:

This study showed that IL-2 treatment leads to a significant increase of immunological parameters, concomitantly with a reduction in vasculature, providing new insight into the cancer mechanisms mediated by IL-2. Moreover, these results suggest that tryptase-positive MCs and Foxp3+ lymphocytes predict clinical outcomes in IL-2-treated patients, highlighting the critical role of the inflammatory response in mesothelioma cancer progression.

Making the case for molecular staging of malignant pleural mesothelioma

Malignant pleural mesothelioma is an aggressive malignancy for which surgical treatment is an option for a subset of patients. A gene ratio test based on the relative expression levels of four genes has been validated in clinical trials to predict which patients will benefit from surgical therapy. A description of the test properties and the independent predictors for outcome are provided.

Mesothelioma: path to multimodality treatment

Multimodality treatment of malignant pleural mesothelioma (MPM) with surgery, radiation therapy, and adjuvant or neoadjuvant chemotherapy is the sole path to extended survival for select patients with favorable prognostic factors. No single-modality approach has produced equivalent results. Much effort has been expended since first recognition of this insidious pleural cancer to elucidate the underlying cause and optimal treatment strategy. Despite recent breakthroughs, the principal barrier to achieving a cure rests with the propensity for disease recurrence in the ipsilateral hemithorax. Despite these limitations, however, the results hold promise for improved survival with further refinement in patient selection and targeted therapy. Other approaches to multimodality treatment have capitalized on an array of innovative technologies in search of the silver bullet strategy that will ultimately undermine the biological behavior demonstrated by MPM. These range from the use of different means of radiation delivery, biological agents, virally mediated gene therapy, photodynamic therapy, and immunotherapy. Additionally, studies using gene ratios will yield more accurate means by which to diagnose, distinguish prognosticators, and more selectively assign patients to aggressive treatments. In light of the current worldwide epidemic, the lessons learned over the past several decades serve as a humbling reminder of the treatment barriers that remain.

Recent advances in mesothelioma staging

Lack of a consensus staging system for malignant pleural mesothelioma has had a profound impact on clinical practice and research, which necessarily relies on comparison of outcomes across multiple institutions and studies for reliable prognostic information. Some lack of agreement arises from the difficulty of conforming this particular cancer to existing staging systems because of its unique biology. The heterogeneous prognosis of patients with differing tumor histology and constant search for new more effective therapies also play a role. Periodic data-driven refinement of staging criteria, based on careful pathologic analysis of histologically homogeneous cohorts, is mandated to provide clinicians with the optimal ability to stratify patients according to survival and select treatments most appropriate for the patient's individual tumor biology.