Talc mediates angiostasis in malignant pleural effusions via endostatin induction

The Association Between Pleural Fluid Exposure and Survival in Pleural Mesothelioma

BACKGROUND

Most patients with malignant pleural mesothelioma (MPM) seek treatment with malignant pleural effusion (MPE). In vitro evidence suggests that MPE may not be a simple bystander of malignancy, but rather potentially has biological properties that improve cancer cell survival and promote cancer progression. If this is the case, MPE management may need to shift from current symptomatic strategies to aggressive fluid removal to impact survival.

RESEARCH QUESTION

Is there an association between pleural fluid exposure and survival in MPM?

STUDY DESIGN AND METHODS

Data from 761 patients who received a diagnosis of MPM between 2008 and 2018 were collected from patient medical records in three UK pleural units. Data included factors previously identified as influencing prognosis in MPM. Medical imaging was reviewed for presence, size, and duration of pleural effusion. Time-dependent covariate analysis of pleural fluid exposure and survival (model included weight loss, serum albumin, hemoglobin, MPM subtype, performance status, chemotherapy, and age) and multivariate Cox regression analysis of pleurodesis and survival were conducted.

RESULTS

Median overall survival was 278 days (interquartile range, 127-505 days; 95% CI, 253-301 days). Pleural fluid exposure duration showed no association with survival (hazard ratio, 1.0; 95% CI, 1.0-1.0). Median survival was 473, 378, and 258 days with complete, partial, and no pleurodesis (P = .008).

INTERPRETATION

Pleurodesis success seems to be associated with improved survival; however, it is unclear whether duration of MPM exposure to pleural fluid is associated with survival within the limitations of this retrospective study. Future prospective studies are required to assess this potentially important mechanism.

The Inflammatory Cytokine Profile of Patients with Malignant Pleural Effusion Treated with Pleurodesis

Patients with malignant pleural effusion (MPE) who underwent successful pleurodesis survive longer than those for whom it fails. We hypothesize that the therapy-induced inflammatory responses inhibit the cancer progression, and thereby lead to a longer survival. Thirty-three consecutive patients with MPE that were eligible for bleomycin pleurodesis between September 2015 and December 2017 were recruited prospectively. Nineteen patients (57.6%) achieved fully or partially successful pleurodesis, while 14 patients either failed or survived less than 30 days after pleurodesis. Two patients without successful pleurodesis were excluded because of missing data. Interleukin (IL)-1 beta, IL-6, IL-10, transforming growth factor beta, tumor necrosis factor alpha (TNF-α), and vascular endothelial growth factor in the pleural fluid were measured before, and after 3 and 24 h of pleurodesis. Their pleurodesis outcome and survival were monitored and analyzed. Patients who underwent successful pleurodesis had a longer survival rate. Patients without successful pleurodesis had significantly higher TNF-α and IL-10 levels in their pleural fluid than in the successful patients before pleurodesis. Following pleurodesis, there was a significant increment of IL-10 in the first three hours in the successful patients. In contrast, significant increments of TNF-α and IL-10 were found in the unsuccessful patients between 3 and 24 h after pleurodesis. The ability to produce specific cytokines in the pleural space following pleurodesis may be decisive for the patient’s outcome and survival. Serial measurement of cytokines can help allocate the patients to adequate treatment strategies. Further study of the underlying mechanism may shed light on cytokine therapies as novel approaches.

Viscum pleurodesis is as effective as talc pleurodesis and tends to have less adverse effect

PURPOSE

Many patients diagnosed with advanced cancer have malignant pleural effusion that does not respond to chemotherapy or radiation therapy. These patients often have respiratory symptoms, especially dyspnea. In order to relieve these symptoms, various procedures including chemical pleurodesis have been performed. Although talc is the most widely used and effective sclerosing agent, there it has various adverse effects. The objective of this study was to determine whether Viscum (ABNOVA Viscum® Fraxini Injection, manufactured by ABNOVA GmbH, Germany) could be used as an agent to replace talc in clinical practice.

METHODS

Data of 56 patients with malignant pleural effusion who received chemical pleurodesis after tube thoracostomy from January 2003 to December 2017 were retrospectively reviewed to analyze clinical course and response after pleurodesis with each agent.

RESULTS

After pleurodesis, changes in numeric rating scale (NRS) was 1.4 ± 1.6 in the talc group and 0.5 ± 1.5 in the Viscum group (p = 0.108). Changes in white blood cell counts after pleurodesis were 4154.8 ± 6710.7 in the talc group and 3487.3 ± 6067.7 in the Viscum group (p = 0.702). Changes in C-reactive protein (CRP) were 9.03 ± 6.86 in the talc group and 6.3 ± 7.5 in the Viscum group (p = 0.366). The success rate of pleurodesis was 93.3% in the talc group and 96% in the Viscum group (p = 0.225).

CONCLUSION

Viscum pleurodesis showed comparable treatment results with talc pleurodesis while its adverse effects such as chest pain and fever tended to be relatively weak.

Management of Malignant Pleural Effusions

Malignant pleural effusion frequently complicates both solid and hematologic malignancies and is associated with high morbidity, mortality, and health care costs. Although no pleura-specific therapy is known to impact survival, both pleurodesis and indwelling pleural catheter (IPC) placement can significantly alleviate symptoms and improve quality of life. The optimal choice of therapy in terms of efficacy and particularly cost-effectiveness depends on patient preferences and individual characteristics, including lung expansion and life expectancy. Attempting chemical pleurodesis through an IPC in the outpatient setting appears to be a particularly promising approach in the absence of a nonexpandable lung.

Chemical pleurodesis - a review of mechanisms involved in pleural space obliteration

Chemical pleurodesis is a therapeutic procedure applied to create the symphysis between the parietal and visceral pleura by intrapleural administration of various chemical agents (e.g. talk, tetracycline, iodopovidone, etc.). The two major clinical conditions treated with chemical pleurodesis are recurrent pleural effusion (PE) and recurrent spontaneous pneumothorax. Although the history of chemical pleurodesis began over a century ago, detailed data on the mechanisms of action of sclerosing agents are highly incomplete. The following article aims to present the state of knowledge on this subject.It is believed that mesothelial cells are the main structural axis of pleurodesis. In response to sclerosing agents they secrete a variety of mediators including chemokines such as interleukin 8 (IL-8) and monocyte chemoattractant protein (MCP-1), as well as growth factors - vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF), basic fibroblast growth factor (bFGF) and transforming growth factor- β (TGF-β). Numerous data suggest that intact mesothelial cells and the above cytokines play a crucial role in the initiation and maintenance of different pathways of pleural inflammation and pleural space obliteration.It seems that the process of pleurodesis is largely nonspecific to the sclerosant and involves the same ultimate pathways including activation of pleural cells, coagulation cascade, fibrin chain formation, fibroblast proliferation and production of collagen and extracellular matrix components. Of these processes, the coagulation cascade with decreased fibrinolytic activity and increased fibrinogenesis probably plays a pivotal role, at least during the early response to sclerosant administration.A better understanding of various pathways involved in pleurodesis may be a prerequisite for more effective and safe use of various sclerosants and for the development of new, perhaps more personalized therapeutic approaches.

Description of Particle Size, Distribution, and Behavior of Talc Preparations Commercially Available Within the United States

BACKGROUND

Widespread use of talc pleurodesis remains controversial for many providers concerned by adverse events such as respiratory failure, which are sometimes fatal. Particle talc size has been implicated in these adverse effects, mainly on the basis of animal studies utilizing large amounts of talc or in observational studies performed on different continents with different talc preparations and doses. Our aim was to determine the particle size and distribution of only the commercially available US-talc preparations and whether the fluid content can affect this distribution.

METHODS

Commercially available US talc was evaluated under scanning electron microscopy and dynamic light scattering (DLS). Distribution of talc particle size was obtained in saline and various protein-based solutions.

RESULTS

Talc particle size by DLS was performed with commercially available Sterile Talc Powder and Sclerosol Intrapleural Aerosol. Sterile Talc Powder demonstrated a median diameter of 26.57 μm with a range of particle sizes from 0.399 μm to 100.237 μm. Sclerosol demonstrated a median diameter of 24.49 μm with a range of particle sizes from 0.224 μm to 100.237 μm. The exposure of talc to a protein rich environment (bovine serum albumin and human pleural fluid) led to the development of measureable, new, larger aggregated particle (>100 μm).

CONCLUSIONS

Currently available US talc seems to have size characteristics similar to previous described "graded" talc preparations. The exposure of talc to a protein rich environment seems to modify the overall distribution of talc particle size when examined by DLS.

Survivin is a negative prognostic factor in malignant pleural effusion

BACKGROUND

Survivin is a well-known member of the inhibitor of apoptosis family, and has been related to increased tumour aggressivity, both in tissue and in pleural fluid.

OBJECTIVES

In patients with malignant pleural effusion, we sought to investigate the changes in pleural fluid survivin concentrations induced by talc instillation into the pleural space. Those changes were also examined in relation to pleurodesis outcome and patient survival.

METHODS

We investigated 84 patients with malignant pleural effusion who underwent talc pleurodesis. Of them, 32 had breast cancer, 25 lung cancer and 27 had mesothelioma. Serial samples of pleural fluid were obtained before thoracoscopy (baseline) and 24 hours thereafter.

RESULTS

Survivin levels were successfully quantified in all pleural fluid samples, and they were significantly higher in samples obtained after thoracoscopic talc poudrage compared with baseline (P < .001). Patients with higher pleural fluid survivin levels at baseline had a significantly poorer pleurodesis outcome (P = .004). A 30 pg/mL cut-off for baseline survivin in pleural fluid predicted failure of pleurodesis with a 54% sensitivity and 79% specificity (P = .009). Moreover, median postpleurodesis survival of patients with baseline survivin levels ≥30 pg/mL was 4 months (range: 0.1-38), compared with 13 months (range: 0.1-259) in patients below that cut-off (P < .001).

CONCLUSION

Elevated pleural fluid survivin concentrations are useful to predict failure of pleurodesis and are associated with shorter survival in patients with malignant pleural effusion.

Pleural fluid osteopontin, vascular endothelial growth factor, and urokinase-type plasminogen activator levels as predictors of pleurodesis outcome and prognosticators in patients with malignant pleural effusion: a prospective cohort study

BACKGROUND

Rapidly growing cancer cells secrete growth-promoting polypeptides and have increased proteolytic activity, contributing to tumor progression and metastasis. Their presentation in malignant pleural effusion (MPE) and their predictive value for the outcome of pleurodesis and survival were studied.

METHODS

Between February 2011 and March 2012, MPE samples were prospectively collected from 61 patients. Twenty-five patients with non-malignant pleural effusion in the same period were included as controls. Pleural fluid osteopontin (OPN), vascular endothelial growth factor (VEGF), and urokinase-type plasminogen activator (uPA) concentrations were measured.

RESULTS

Patients with MPE had higher pleural fluid OPN, VEGF, and uPA concentrations than those with non-malignant pleural effusion, but only differences in VEGF were statistically significant (p = 0.045). Patients with distant metastases had significantly elevated pleural fluid VEGF concentrations than those without (p = 0.004). Pleural fluid OPN, VEGF, and uPA concentrations were positively correlated in most patients. However, there was no significant difference in pleural fluid OPN, VEGF, and uPA concentrations between patients with successful pleurodesis and those without. There was also no significant difference in cancer-specific survival between sub-groups with higher and lower pleural fluid OPN, VEGF, or uPA concentrations. Patients with successful pleurodesis had significantly longer cancer-specific survival than those without (p = 0.015).

CONCLUSIONS

Pleural fluid OPN, VEGF, and uPA concentrations are elevated in MPE but are not satisfactory predictors of pleurodesis outcome or survival. Patients with higher pleural fluid VEGF concentration have higher risk of distant metastasis. Evaluating the benefits of therapy targeting the VEGF pathway in these patients warrants further studies.

Pleural mesothelial cells in pleural and lung diseases

During development, the mesoderm maintains a complex relationship with the developing endoderm giving rise to the mature lung. Pleural mesothelial cells (PMCs) derived from the mesoderm play a key role during the development of the lung. The pleural mesothelium differentiates to give rise to the endothelium and smooth muscle cells via epithelial-to-mesenchymal transition (EMT). An aberrant recapitulation of such developmental pathways can play an important role in the pathogenesis of disease processes such as idiopathic pulmonary fibrosis (IPF). The PMC is the central component of the immune responses of the pleura. When exposed to noxious stimuli, it demonstrates innate immune responses such as Toll-like receptor (TLR) recognition of pathogen associated molecular patterns as well as causes the release of several cytokines to activate adaptive immune responses. Development of pleural effusions occurs due to an imbalance in the dynamic interaction between junctional proteins, n-cadherin and β-catenin, and phosphorylation of adherens junctions between PMCs, which is caused in part by vascular endothelial growth factor (VEGF) released by PMCs. PMCs play an important role in defense mechanisms against bacterial and mycobacterial pleural infections, and in pathogenesis of malignant pleural effusion, asbestos related pleural disease and malignant pleural mesothelioma. PMCs also play a key role in the resolution of inflammation, which can occur with or without fibrosis. Fibrosis occurs as a result of disordered fibrin turnover and due to the effects of cytokines such as transforming growth factor-β, platelet-derived growth factor (PDGF), and basic fibroblast growth factor; which are released by PMCs. Recent studies have demonstrated a role for PMCs in the pathogenesis of IPF suggesting their potential as a cellular biomarker of disease activity and as a possible therapeutic target. Pleural-based therapies targeting PMCs for treatment of IPF and other lung diseases need further exploration.

Switching off malignant pleural effusion formation-fantasy or future?

Malignant pleural effusion (MPE) is common and difficult to treat. In the vast majority of patients the presence of MPE heralds incurable disease, associated with poor quality of life, morbidity and mortality. Current therapeutic approaches are inefficient and merely offer palliation of associated symptoms. Recent scientific progress has shed light in the biologic processes governing the mechanisms behind the pathobiology of MPE. Pleural based tumors interfere with pleural fluid drainage, as well as the host vasculature and immune system, resulting in decreased fluid absorption and increased pleural fluid production via enhanced plasma extravasation into the pleural space. In order to achieve this feat, pleural based tumors must elicit critical vasoactive events in the pleura, thus forming a favorable microenvironment for tumor dissemination and MPE development. Such properties involve specific transcriptional signaling cascades in addition to secretion of important mediators which attract and activate host cell populations which, in turn, impact tumor cell functions. The dissection of the biologic steps leading to MPE formation provides novel therapeutic targets and recent research findings provide encouraging results towards future therapeutic innovations in MPE management.

Efficacy and safety of talc pleurodesis for malignant pleural effusion: a meta-analysis

Background

Talc pleurodesis has been widely used to control malignant pleural effusion; however, it is still not clear whether talc pleurodesis is more effective than other local therapies. We performed a meta-analysis to evaluate the efficacy and safety of talc pleurodesis in the management of malignant pleural effusion.

Methods

PubMed, Embase, and Web of Science were searched for English-language studies of clinical controlled trials comparing talc pleurodesis with control therapies until August 8, 2013. Success rate and incidence of adverse events were evaluated. Relative risks were estimated using random- or fixed- effects model and statistical heterogeneity was assessed using I² test.

Results

Twenty trials involving 1,525 patients with malignant pleural effusion were included. The success rate of talc pleurodesis was significantly higher than that of control therapies (relative risk, 1.21; 95% confidence interval, 1.01–1.45; p = 0.035) with similar adverse events. In addition, thoracoscopic talc poudrage was more effective than bedside talc slurry (relative risk, 1.12; 95% confidence interval, 1.01–1.23; p = 0.026).

Conclusions

The current evidences suggested the benefit for talc pleurodesis in the treatment of malignant pleural effusion. Talc pleurodesis, especially thoracoscopic talc poudrage pleurodesis, should be performed in patients with malignant pleural effusion, especially those with life-expectancy longer than one month.

From "awake" to "monitored anesthesia care" thoracic surgery: A 15 year evolution

Although general anesthesia still represents the standard when performing thoracic surgery, the interest toward alternative methods is increasing. These have evolved from the employ of just local or regional analgesia techniques in completely alert patients (awake thoracic surgery), to more complex protocols entailing conscious sedation and spontaneous ventilation. The main rationale of these methods is to prevent serious complications related to general anesthesia and selective ventilation, such as tracheobronchial injury, acute lung injury, and cardiovascular events. Trends toward shorter hospitalization and reduced overall costs have also been indicated in preliminary reports. Monitored anesthesia care in thoracic surgery can be successfully employed to manage diverse oncologic conditions, such as malignant pleural effusion, peripheral lung nodules, and mediastinal tumors. Main non-oncologic indications include pneumothorax, emphysema, pleural infections, and interstitial lung disease. Furthermore, as the familiarity with this surgical practice has increased, major operations are now being performed this way. Despite the absence of randomized controlled trials, there is preliminary evidence that monitored anesthesia care protocols in thoracic surgery may be beneficial in high-risk patients, with non-inferior efficacy when compared to standard operations under general anesthesia. Monitored anesthesia care in thoracic surgery should enter the armamentarium of modern thoracic surgeons, and adequate training should be scheduled in accredited residency programs.

Recombinant human endostatin (endostar) decreased recurrent ascites, pleural fluid and ascitic VEGF in a case of advanced mesothelioma

We report a case of 43-year-old male with advanced malignant mesothelioma (MM) with a large amount of fluid in the pleural and peritoneal cavity. The addition of endostar to the gemcitabine-cisplatin regimen gave a prompt and significant improvement of clinical symptoms and disappearance of ascites. The patient is still progression free after 27 months. Endostar, in combination with chemotherapy should be explored in the treatment of MM, especially its effect on pleural and ascitic fluid.

Recombinant human endostatin endostar suppresses angiogenesis and lymphangiogenesis of malignant pleural effusion in mice

Background

Malignant pleural effusion (MPE) is a common complication of lung cancer. One widely used treatment for MPE is Endostar, a recombined humanized endostatin based treatment. However, the mechanism of this treatment is still unclear. The aim of this study was to investigate the effects of Endostar in mice with MPE.

Methods and Materials

Lewis lung carcinoma (LLC) cell line expressing enhanced green fluorescent protein (EGFP) was injected into pleural cavity to establish MPE mice model. Mice were randomly divided into four groups. High dose of Endostar (30 mg/kg), low dose of Endostar (8 mg/kg), normal saline, or Bevacizumab (5 mg/kg) was respectively injected into pleural cavity three times with 3-day interval in each group. Transverse computed tomography (CT) was performed to observe pleural fluid formation 14 days after LLC cells injection. Mice were anesthetized and sacrificed 3 days after final administration. The volume of pleural effusion n was measured using 1 ml syringe. Micro blood vessel density (MVD), Lymphatic micro vessel density (LMVD), the expression level of vascular endothelial growth factor A (VEGF-A) and VEGF-C were observed by immunohistochemistry (IHC) staining.

Results

The volume of pleural effusion as well as the number of pleural tumor foci, MVD and the expression of VEGF-A were significantly reduced in high dose of Endostar treat group. More importantly, LMVD and the expression of VEGF-C were markedly lower in treat group than those in the other three control groups.

Conclusion

Our work demonstrated that Endostar played an efficient anti-cancer role in MPE through its suppressive effect on angiogenesis and lymphangiogenesis, which provided a certain theoretical basis for the effectiveness of Endostar on the MPE treatment.

Malignant pleural effusion: tumor-host interactions unleashed

Malignant pleural effusion (MPE) poses a significant clinical problem. Current nonetiologic management is suboptimal in terms of efficacy and safety. In light of recent research progress, we propose herein a new view of MPE development, which may rapidly translate into meaningful changes in therapeutics. In addition to tumor-induced impairment of pleural fluid drainage, pertinent findings point toward another pathway to MPE formation: a vicious loop of interactions between pleural-based tumor cells and the host vasculature and immune system that results in increased net fluid production via enhanced plasma extravasation into the pleural space. The ability of tumor cells to trigger this cascade likely rests on a specific and distinct transcriptional repertoire, which results in important vasoactive events in the pleural space. Although the characterization of tumor-derived factors responsible for MPE development is in the making, an additional, indirect path to MPE was recently demonstrated: tumor cells recruit and co-opt host cells and mediators, which, in turn, amplify tumor cell-primed fluid leakage and impact tumor cell functions. Importantly, recent evidence suggests that the biologic events that culminate in clinical MPE are likely amenable to therapeutic inhibition and even prevention. In this perspective, the scientific basis for an update of current concepts of MPE formation is highlighted. Key questions for future research are posed. Finally, a vision for novel, effective, safe, and convenient treatment modalities that can be offered to outpatients with MPE is set forth.

Role of talc modulation on cytokine activation in cancer patients undergoing pleurodesis

We investigate the mechanism of talc pleurodesis (TP) in 20 patients with recurrent malignant pleural effusion and 10 patients with nonmalignant pleural effusions. We measured IL-8 levels before and 6 h after TP and find a significant threefold increase (2.26 ng/mL ± 0.7 to 6.5 ng/mL 0.1), which explains the recruitment of inflammatory cells in these patients. We hypothesize that TP is enable by stimulating the mesothelial cells (MS) to secrete FGF. A significant tenfold increase in FGF-b (0.05 ng/mL ± 0.02 to 0.44 ng/mL 0.6) was seen 24 h after talc instillation (P < 0.04). In order to examine whether FGF-b is secreted by MS cells, MS recovered from CHF patients with recurrent pleural effusions were cultured for 48 h in the presence or absence of increasing concentrations of talc (from 100 ng/mL to 1 mg/mL). They produced significant levels of FGF-b in a dose dependent manner (P < 0.005). We hypothesized that a successful pleurodesis involves an early enhanced recruitment of inflammatory cells through a rise of IL-8 followed by enrollment of fibroblasts from the submesothelial space through increased mesothelial FGF-b production.

Mechanisms of pleurodesis

Pleurodesis aims to obliterate the pleural space by producing extensive adhesion of the visceral and parietal pleura, in order to control relapse of either pleural effusions (mostly malignant) or pneumothorax. A tight and complete apposition between the two pleural layers is a necessary condition to obtain a successful pleurodesis, but--besides this mechanical aspect--there are many biological mechanisms that appear to be common to most of the sclerosing agents currently used. Following intrapleural application of the sclerosing agent, diffuse inflammation, pleural coagulation-fibrinolysis imbalance (favoring the formation of fibrin adhesions), recruitment and subsequent proliferation of fibroblasts, and collagen production are findings in the pleural space. The pleural mesothelial lining is the primary target for the sclerosant and plays a pivotal role in the whole pleurodesis process, including the release of several mediators like interleukin-8, transforming growth factor-β and basic fibroblast growth factor. When the tumor burden is high, normal mesothelial cells are scarce, and consequently the response to the sclerosing agent is decreased, leading to failure of pleurodesis. Also, the type of tumor in the pleural cavity may also affect the outcome of pleurodesis (diffuse malignant mesothelioma and metastatic lung carcinomas have a poorer response). There is general agreement that talc obtains the best results, and there are also preliminary experimental studies suggesting that it can induce apoptosis in tumor cells and inhibit angiogenesis, thus contributing to a better control of the malignant pleural effusion. There is concern about complications (possibly associated with talc but other agents as well) related to systemic inflammation and possible activation of the coagulation cascade. In order to prevent extrapleural talc dissemination, large-particle talc is recommended. Although it could--to some degree--interfere with the mechanisms leading to pleurodesis and a carefully balanced clinical decision has therefore to be made, prophylactic treatment with subcutaneous heparin is recommended during hospitalization (immediately before and after the pleurodesis procedure).

The angiogenetic pathway in malignant pleural effusions: Pathogenetic and therapeutic implications

Increased permeability of the pleural microvasculature is generally attributed to the substances that are released in inflammatory and malignant pleural effusions, although the exact pathogenetic mechanisms of malignant pleural effusions are unclear. Current therapies used to prevent the re-accumulation of pleural fluid and relieve symptoms are of variable efficacy and may cause serious adverse effects. Understanding the mechanisms of fluid accumulation would hopefully permit the development of more specific, effective and safer treatment modalities. Angiogenesis, pleural vascular increased permeability and inflammation are considered central to the pathogenesis of malignant pleural effusions. Vascular endothelial growth factor (VEGF) is a member of the VEGF/platelet-derived factor gene family and consists of at least six isoforms. Since it was shown that VEGF contributes to the formation of malignant pleural effusions, there have been some attempts to implicate, therapeutically, this finding using different molecules (ZD6474, PTK 787 and bevacizumab). However, the role of the biological axis of VEGF and angiopoietins needs further investigation in both the pathogenesis and the treatment of malignant pleural effusion. In both non-small-cell lung carcinoma and breast cancer, it has been shown that the ligand for CXCR4, CXCL12 or SDF-1α, exhibited peak levels of expression in organs that were the preferred destination for their respective metastases. Recent findings imply that new therapeutic strategies aimed at blocking the SDF-1-CXCR4 axis may have significant applications for patients by modulating the trafficking of hemato/lymphopoietic cells and inhibiting the metastatic behavior of tumor cells as well. The purpose of this report is to review novel pathogenetic and therapeutic implications regarding the angiogenetic pathways in malignant pleural effusions.

Diagnosis and management of malignant pleural effusions

Malignant pleural effusions (MPEs) complicate the clinical course of patients with a broad array of malignancies, which are most often due to lymphomas or carcinomas of the breast, lung, gastrointestinal tract or ovaries. Patients may present with a MPE as the initial manifestation of a cancer or develop an effusion during the advanced phases of a known malignancy. In either circumstance, the median survival after presentation with a MPE is 4 months. Effusions may result from direct pleural invasion (MPE) or indirect effects (paraneoplastic effusions), such as impairment of fluid efflux from the pleural space by lymphatic obstruction or pleural effects of cancer radiation or drug therapy. Because only 50% of patients with cancer who develop a pleural effusion during their clinical course have a MPE, careful evaluation of the effusion to establish its aetiology is required to direct therapy. Management is palliative with interventions directed towards decreasing the volume of intrapleural fluid and the severity of associated symptoms.

Pathophysiology of the pleura

The pleural mesothelial cell is an essential cell in maintaining the normal homeostasis of the pleural space and it is also a central component of the pathophysiologic processes affecting the pleural space. In this review, we will review the defense mechanisms of the pleural mesothelium and changes in pleural physiology as a result of inflammatory, infectious, and malignant conditions with a focus on cytokine and chemokine networks. We will also review the processes involved in the pathogenesis of pleural fibrosis.

Recent advances in the diagnosis and management of malignant pleural effusions

Malignant pleural effusions (MPEs) are an important complication for patients with intrathoracic and extrathoracic malignancies. Median survival after diagnosis of an MPE is 4 months. Patients can present with an MPE as a complication of far-advanced cancer or as the initial manifestation of an underlying malignancy. Common cancer types causing MPEs include lymphomas, mesotheliomas, and carcinomas of the breast, lung, gastrointestinal tract, and ovaries. However, almost all tumor types have been reported to cause MPEs. New imaging modalities assist the evaluation of patients with a suspected MPE; however, positive cytologic or tissue confirmation of malignant cells is necessary to establish a diagnosis. Even in the presence of known malignancy, up to 50% of pleural effusions are benign, underscoring the importance of a firm diagnosis to guide therapy. Rapidly evolving interventional and histopathologic techniques have improved the diagnostic yield of standard cytology and biopsy. Management of an MPE remains palliative; it is critical that the appropriate management approach is chosen on the basis of available expertise and the patient's clinical status. This review summarizes the pathogenesis, diagnosis, and management of MPE. Studies in the English language were identified by searching the MEDLINE database (1980-2007) using the search terms pleura, pleural, malignant, pleurodesis, and thoracoscopy.

Receptor EphA2 activation with ephrinA1 suppresses growth of malignant mesothelioma (MM)

The objective of this study was to understand the possible mechanisms of activation of receptor EphA2 by its ligand ephrinA1 in malignant mesothelioma cell (MMC) growth. Activation of receptor EphA2 by its ligand ephrinA1 triggered the phosphorylation of EphA2. Ligand activation of EphA2 also induced phosphorylation of ERK1/2 and significantly decreased MMC proliferation. Ligand activated and ephrinA1 vector (pcDNA/EFNA1) transfected MMC demonstrated decreased clonal growth in 3-D matrigels when compared to resting MMC. These studies suggest that EphA2 activation by its ligand ephrinA1 transmits intracellular signals from cell membrane to nucleus via ERK1/2 signaling cascade and inhibits MM growth.