The emerging role of the lung microbiome and its importance in non-small cell lung cancer diagnosis and treatment.

Over the last 10 years, with the development of culture-free bacterial identification techniques, understanding of how the microbiome influences diseases has increased exponentially and has highlighted potential opportunities for its use as a diagnostic biomarker and interventional target in many diseases including malignancy. Initial research focused on the faecal microbiome since it contains the densest bacterial populations and many other mucosal sites, such as the lungs, were until recently thought to be sterile. However, in recent years, it has become clear that the lower airways are home to a dynamic bacterial population sustained by the migration and elimination of microbes from the gastrointestinal and upper airway tracts. As in the gut, the lung microbiome plays an important role in regulating mucosal immunity and maintaining the balance between immune tolerance and inflammation. Studies to date have all shown that the lung microbiome undergoes significant changes in the setting of pulmonary disease. In lung cancer, animal models and small patient cohort studies have suggested that microbiome dysbiosis may not only impact tumour progression and response to therapy, particularly immunotherapy, but also plays a key role in cancer pathogenesis by influencing early carcinogenic pathways. These early results have led to concerted efforts to identify microbiome signatures that represent diagnostic biomarkers of early-stage disease and to consider modulation of the lung microbiome as a potential therapeutic strategy. Lung microbiome research is in its infancy and studies to date have been small, single centre with significant methodological variation. Large, multicentre longitudinal studies are needed to establish the clinical potential of this exciting field.

Asbestos-related lung cancer: Clinical characteristics and survival outcomes in an Australian cohort seeking workers compensation.

BACKGROUND AND OBJECTIVES: Due to difficulties in identifying sufficient-sized cohorts there remains uncertainty about prognostic and clinical differences that may be unique to asbestos-related lung cancer (ARLC). In this study, we use the Helsinki Criteria to define a group of ex-workers with lung cancer attributable to asbestos exposure and investigate differences that may exist. METHODS: A total of 529 patients seeking workers' compensation for their lung cancer were assigned to either ARLC or the non-ARLC based on parameters defined in the Helsinki Criteria. Clinical and survival details were collected and analyzed. RESULTS: In our study population, ARLC patients were on average older (72.1 ± 7.8) than non-ARLC patients (66.5 ± 10.2, P < 0.001) and were more likely to be diagnosed as a result of incidental findings or screening program (P < 0.001). The groups were similar in terms of clinical characteristics with the only difference being that plaques were more prevalent among ARLC patients (P < 0.001). Differences were observed for median overall survival (OS), ARLC (9 months) and non-ARLC (13 months, P = 0.005), as well for treatment (P = 0.01). After adjusting for age, however, these differences disappeared. CONCLUSIONS: Age at diagnosis, pleural plaques, and asymptomatic presentation were the attributes that we identified as significantly different between asbestos-related cancer and other lung cancers. In this cohort, ARLC patients were older diagnosis and with worse overall survival.

Efficacy of immunotherapy in KRAS-mutant non-small-cell lung cancer with comutations.

KRAS-mutant non-small-cell lung cancer is the most common molecular driver of lung adenocarcinoma in western populations. No KRAS specific therapy has been approved by the US FDA until 2021. Despite significant heterogeneity in comutations, patients typically receive single-agent immunotherapy or chemoimmunotherapy as standard first-line therapy. It is unclear whether KRAS mutations predict outcomes with immunotherapy; however, there is emerging data suggesting improved outcomes in patients with a TP53 comutation and worse outcomes in patients with a STK11/LKB1 or KEAP1 comutation.

Emerging biological therapies for the treatment of malignant pleural mesothelioma.

Introduction: Malignant pleural mesothelioma (MPM) has limited treatment options with minimal new therapy approvals for unresectable disease in the past 15 years. However, considerable work has occurred to develop immunotherapies and biomarker driven therapy to improve patient outcomes over this period.Areas covered: This review examines current standard of care systemic therapy in the first- and second line setting. The last 12 months has seen 2 significant trials (Checkmate 743 and CONFIRM) which provide evidence supporting the role of immunotherapy in the management of MPM. Further trials are underway to assess the role of combination chemoimmunotherapy and personalized therapy. Additionally, a large number of clinical trials are ongoing to assess the efficacy of oncoviral, dendritic cell, anti-mesothelin and chimeric antigen receptor T cell therapy in the treatment of MPM.Expert opinion: Recent Phase III trial results have established a role for immunotherapy in the management of MPM. The optimal sequencing and combination of chemotherapy and immunotherapy remains to be determined. Novel therapies for MPM are promising however efficacy remains to be determined and issues remain regarding access to and delivery of these therapies.

Why do delays to diagnosis and treatment of lung cancer occur? A mixed methods study of insights from Australian clinicians.

AIMS: Delays in lung cancer diagnosis and treatment can impact survival. We explored reasons for delays experienced by patients with lung cancer to identify themes and strategies for improvement. METHODS: We used national timeframe recommendations and standardized definitions to identify General Practitioners and specialists caring for 34 patients who experienced delays in our previous Medicare data linkage study. Clinicians participated in a survey and interview, including qualitative (exploratory, open-ended questions) and quantitative (rating scales) components. Exploratory content analysis, cross-case triangulation, and descriptive statistics were performed. Krippendorff's coefficient was used to assess level of agreement between clinicians and patients, and among clinicians, on perceived delays. RESULTS: Overall, 27 out of 50 (54%) eligible clinicians participated (including 11 respiratory physicians and seven medical oncologists). Dominant themes for perceived causes of delay included referral barriers, limited General Practitioner (GP) awareness of subtle clinical presentations, insufficient radiology interpretation, and lack of cancer coordinators. "Unavoidable" delays may occur due to clinical circumstances. Awareness and uptake of referral and timeframe guidelines were low, with clinicians using professional networks over guidelines. There was no consistent agreement on perceived delays between patients and clinicians, and among clinicians (Krippendorff's coefficient .03 [P = .8]). CONCLUSIONS: Strategies for minimizing avoidable delays include efficient GP to specialist referral and more lung cancer coordinators to assist with patient expectations and waitlist management. Clinicians' reliance on experience, rather than guidelines, indicates need to review guideline utility. Raising awareness of benchmarks and unavoidable barriers may recalibrate perceptions of "delays" to diagnosis and treatment of lung cancer.

Standard-Dose Osimertinib in EGFR-Mutated Non-Small-Cell Lung Adenocarcinoma With Leptomeningeal Disease.

PURPOSE: Leptomeningeal disease (LMD) in epidermal growth factor receptor (EGFR)-mutant lung adenocarcinoma is associated with a poor prognosis and limited treatment options. Osimertinib is a potent third-generation EGFR tyrosine kinase inhibitor with confirmed CNS penetration. This study reports on outcomes of patients with EGFR-mutated non-small-cell lung cancer who developed LMD and were subsequently treated with osimertinib. METHODS: We identified patients treated with osimertinib 80 mg PO daily under a compassionate access scheme across nine tertiary Australian institutes between July 2017 and July 2020. Patient demographics, tumor characteristics, and treatment history were collected. Median overall survival, median progression-free survival, disease control rates (DCR), and overall response rates (ORR) were assessed. Kaplan-Meier analysis was performed and descriptive statistics were used. RESULTS: Thirty-nine patients were analyzed of which 74% were female. Exon 19 deletions (49%) and L858R point mutations (41%) were the most common EGFR mutations. Forty-nine percentage of patients were Eastern Cooperative Oncology Group 1. The median duration of osimertinib therapy was 6 months. The extracranial DCR and ORR were 60% and 54%, and the intracranial DCR and ORR were 68% and 53%, respectively. Median overall survival was 10.5 months (95% CI, 8.17 to 15.05 months). CONCLUSION: There are limited treatment options for LMD in EGFR-positive lung cancer, and osimertinib at a dose of 80 mg daily is an active therapeutic option for these patients.

Durvalumab with first-line chemotherapy in previously untreated malignant pleural mesothelioma (DREAM): a multicentre, single-arm, phase 2 trial with a safety run-in.

BACKGROUND: There is a strong unmet need to improve systemic therapy in mesothelioma. Chemotherapy with cisplatin and pemetrexed improves survival in malignant pleural mesothelioma, and immune checkpoint inhibitors are an emerging treatment in this disease. We aimed to evaluate the activity of durvalumab, an anti-PD-L1 antibody, given during and after first-line chemotherapy with cisplatin and pemetrexed in patients with advanced malignant pleural mesothelioma. METHODS: DREAM was a multicentre, single-arm, open-label, phase 2 trial done in nine hospitals in Australia. Eligible patients were aged 18 years or older and had histologically confirmed malignant pleural mesothelioma considered unsuitable for cancer-directed surgery, an Eastern Cooperative Oncology Group performance status of 0 or 1, and measurable disease as per the modified Response Evaluation Criteria in Solid Tumors version 1.0 (mRECIST) for mesothelioma that was previously untreated with systemic therapy. All histological subtypes were eligible. The first six participants were treated for two cycles in a safety run-in. All participants received cisplatin 75 mg/m2, pemetrexed 500 mg/m2, and durvalumab 1125 mg intravenously on day 1 of a 3-weekly schedule for a maximum of six cycles. Change from cisplatin to carboplatin with an area under the curve of 5 was permitted. Durvalumab was continued for a maximum of 12 months. The primary endpoint was progression-free survival at 6 months, measured according to mRECIST for malignant pleural mesothelioma and analysed in the intention-to-treat population. Safety analyses included all participants who receive at least one dose of any study drug. This study is registered with the Australia New Zealand Clinical Trials Registry, ACTRN12616001170415. FINDINGS: Between Dec 28, 2016, and Sept 27, 2017, 55 participants were enrolled. 54 patients were eligible and were followed up for a median of 28·2 months (IQR 26·5-30·2). 31 (57%; 95% CI 44-70) of 54 patients were alive and progression-free at 6 months. The most common grade 3-4 adverse events were neutropenia (seven [13%] patients), nausea (six [11%]), and anaemia (four [7%]). A total of 60 serious adverse events occurred in 29 participants, five of which were considered possibly related to durvalumab. Five patients died during the study treatment; none of these five deaths were attributed to study treatment. INTERPRETATION: The combination of durvalumab, cisplatin, and pemetrexed has promising activity and an acceptable safety profile that warrants further investigation in a randomised phase 3 trial. FUNDING: AstraZeneca.

Times to Diagnosis and Treatment of Lung Cancer in New South Wales, Australia: A Multicenter, Medicare Data Linkage Study.

INTRODUCTION: Earlier access to lung cancer specialist (LCS) care improves survival. We examined times to diagnosis and treatment of patients with lung cancer in rural and metropolitan New South Wales (NSW) Australia, benchmarked against recent timeframe recommendations. MATERIALS AND METHODS: Semistructured interviews of recently diagnosed patients with lung cancer from five NSW cancer centers were used to determine standardized time intervals to diagnosis and treatment, triangulated with Medicare data linkage and medical records. We used descriptive statistics to evaluate the primary end points of median time intervals from general practitioner (GP) referral to first LCS visit (GP-LCS interval) and to treatment start (Secondary Care interval). Univariable and multivariable analyses were used to study associations with delays in end points. Post hoc survival analyses were performed. RESULTS: Data linkage was performed for 125 patients (68% stage IV; 69% metropolitan), with 108 interviewed. The median GP-LCS interval was 4 days, with 83% of patients seeing an LCS within the recommended 14 days. The median Secondary Care interval was 42 days (52% within 42 days). There were no significant differences between time intervals faced by rural and metropolitan patients overall, although metropolitan patients took 18 days less than rural counterparts to commence radiation/chemoradiation (95% CI, -33.2 to -2.54; P = .02). One third of patients perceived delays. Delays did not affect survival. CONCLUSION: Rural and metropolitan NSW patients face comparable time lines to diagnosis and treatment of lung cancer. Most patients are seen by an LCS within recommended timeframes, but transition through Secondary Care and addressing patient expectations could be improved.

How long is too long? A scoping review of health system delays in lung cancer.

Earlier access to lung cancer specialist (LCS) care improves survival, highlighting the need for streamlined patient referral. International guidelines recommend 14-day maximum time intervals from general practitioner (GP) referral to first LCS appointment ("GP-LCS interval"), and diagnosis to treatment ("treatment interval"). We compared time intervals in lung cancer care against timeframe benchmarks, and explored barriers and facilitators to timely care.We conducted a scoping review of literature from MEDLINE, Embase, Scopus and hand searches. Primary end-points were GP-LCS and treatment intervals. Performance against guidelines and factors responsible for delays were explored. We used descriptive statistics and nonparametric Wilcoxon rank sum tests to compare intervals in studies reporting fast-track interventions.Of 1343 identified studies, 128 full-text articles were eligible. Only 33 (26%) studies reported GP-LCS intervals, with an overall median of 7 days and distributions largely meeting guidelines. Overall, 52 (41%) studies reported treatment intervals, with a median of 27 days, and distributions of times falling short of guidelines. There was no effect of fast-track interventions on reducing time intervals. Lack of symptoms and multiple procedures or specialist visits were suggested causes for delay.Although most patients with lung cancer see a specialist within a reasonable timeframe, treatment commencement is often delayed. There is regional variation in establishing timeliness of care.

Delays to diagnosis and treatment of lung cancer in Australia: healthcare professional perceptions of actual versus acceptable timeframes.

BACKGROUND: Streamlined referral to specialist care impacts lung cancer outcomes. AIM: To examine Australian healthcare professionals' (HCP) perceptions of the timeliness of pathways to diagnosis and treatment for people with lung cancer, compared against timeframe guidelines. METHODS: A 21-item survey of HCP evaluating patient waiting times to diagnosis and treatment of lung cancer was distributed through two Australian conferences, a national Multidisciplinary Team directory and email. Main outcome measures were HCP estimates of actual and acceptable waiting times in their practice and factors contributing to perceived delays. RESULTS: A total of 135 responses was obtained from HCP working in secondary healthcare who had recent clinical experience treating lung cancer patients. While 79% believed a diagnosis of lung cancer should be obtained within 14 days of first clinical suspicion, only 56% estimated that this occurred in their practice due mainly to delays in primary care. Most HCP (81%) estimated that patients receive treatment within 28 days of seeing a specialist, but 28% believed a wait of >14 days to treatment was a 'delay', generally due to resource limitations. In general, most HCP estimates of time spent in primary care were longer than those in the literature, while estimates for secondary care were shorter. CONCLUSIONS: Australian HCP treating lung cancer patients perceive a mismatch between acceptable and estimated waiting times to diagnosis and treatment of lung cancer due to patient, provider and system factors. If perceived delays are justified, it is unclear whether HCP overestimate times spent by patients in primary care or underestimate delays in secondary care. Variations in HCP expectations need to be addressed.

Safety and activity of microRNA-loaded minicells in patients with recurrent malignant pleural mesothelioma: a first-in-man, phase 1, open-label, dose-escalation study.

BACKGROUND: TargomiRs are minicells (EnGeneIC Dream Vectors) loaded with miR-16-based mimic microRNA (miRNA) and targeted to EGFR that are designed to counteract the loss of the miR-15 and miR-16 family miRNAs, which is associated with unsuppressed tumour growth in preclinical models of malignant pleural mesothelioma. We aimed to assess the safety, optimal dosing, and activity of TargomiRs in patients with malignant pleural mesothelioma. METHODS: In this first-in-man, open-label, dose-escalation phase 1 trial at three major cancer centres in Sydney (NSW, Australia), we recruited adults (aged ≥18 years) with a confirmed diagnosis of malignant pleural mesothelioma, measurable disease, radiological signs of progression after previous chemotherapy, Eastern Cooperative Oncology Group performance status of 0 or 1, life expectancy of 3 months or more, immunohistochemical evidence of tumour EGFR expression, and adequate bone marrow, liver, and renal function. Patients were given TargomiRs via 20 min intravenous infusion either once or twice a week (3 days apart) in a traditional 3 + 3 dose-escalation design in five dose cohorts. The dose-escalation steps planned were 5 × 109, 7 × 109, and 9 × 109 TargomiRs either once or twice weekly, but after analysis of data from the first eight patients, all subsequent patients started protocol treatment at 1 × 109 TargomiRs. The primary endpoints were to establish the maximum tolerated dose of TargomiRs as measured by dose-limiting toxicity, define the optimal frequency of administration, and objective response (defined as the percentage of assessable patients with a complete or partial response), duration of response (defined as time from the first evidence of response to disease progression in patients who achieved a response), time to response (ie, time from start of treatment to the first evidence of response) and overall survival (defined as time from treatment allocation to death from any cause). Analyses were based on the full analysis set principle, including every patient who received at least one dose of TargomiRs. The study was closed for patient entry on Jan 3, 2017, and registered with ClinicalTrials.gov, number NCT02369198, and the Australian Registry of Clinical Trials, number ACTRN12614001248651. FINDINGS: Between Sept 29, 2014, and Nov 24, 2016, we enrolled 27 patients, 26 of whom received at least one TargomiR dose (one patient died before beginning treatment). Overall, five dose-limiting toxicities were noted: infusion-related inflammatory symptoms and coronary ischaemia, respectively, in two patients given 5 × 109 TargomiRs twice weekly; anaphylaxis and cardiomyopathy, respectively, in two patients given 5 × 109 TargomiRs once weekly but who received reduced dexamethasone prophylaxis; and non-cardiac pain in one patient who received 5 × 109 TargomiRs once weekly. We established that 5 × 109 TargomiRs once weekly was the maximum tolerated dose. TargomiR infusions were accompanied by transient lymphopenia (25 [96%] of 26 patients), temporal hypophosphataemia (17 [65%] of 26 patients), increased aspartate aminotransferase or alanine aminotranferase (six [23%] of 26 patients), and increased alkaline phosphatase blood concentrations (two [8%]). Cardiac events occurred in five patients: three patients had electrocardiographic changes, one patient had ischaemia, and one patient had Takotsubo cardiomyopathy. Of the 22 patients who were assessed for response by CT, one (5%) had a partial response, 15 (68%) had stable disease, and six (27%) had progressive disease. The proportion of patients who achieved an objective response was therefore one (5%) of 22, and the duration of the objective response in that patient was 32 weeks. Median overall survival was 200 days (95% CI 94-358). During the trial, 21 deaths occurred, of which 20 were related to tumour progression and one was due to bowel perforation. INTERPRETATION: The acceptable safety profile and early signs of activity of TargomiRs in patients with malignant pleural mesothelioma support additional studies of TargomiRs in combination with chemotherapy or immune checkpoint inhibitors. FUNDING: Asbestos Diseases Research Foundation.

Tumor Suppressor microRNAs Contribute to the Regulation of PD-L1 Expression in Malignant Pleural Mesothelioma.

INTRODUCTION: The upregulation of programmed death ligand 1 (PD-L1) is found in many cancers and contributes to evasion of the host's immune defense. In malignant pleural mesothelioma (MPM), PD-L1 expression is associated with the nonepithelioid histological subtype and poor prognosis, but the pathways involved in control of PD-L1 expression in MPM are poorly understood. To address one possible means of PD-L1 regulation we investigated the relationship between dysregulated microRNA levels and PD-L1 expression. METHODS: PD-L1 expression was analyzed by immunohistochemistry in tissue microarrays prepared from samples from patients undergoing an operation (pleurectomy with or without decortication). MicroRNA expression was analyzed by reverse-transcriptase quantitative polymerase chain reaction. Regulation of PD-L1 expression in cell lines was assessed after transfection with microRNA mimics and small interfering RNAs. Interaction between microRNAs and PD-L1 was analyzed by using argonaute-2 immunoprecipitation and a luciferase reporter assay. RESULTS: In a series of 72 patients with MPM, 18 (25%) had positive PD-L1 staining, and this was more common in patients with the nonepithelioid subtype (p = 0.01). PD-L1 expression was associated with poor survival (median overall survival 4.0 versus 9.2 months with positive versus negative PD-L1 expression [p < 0.001]), and in multivariate analyses, PD-L1 expression remained a significant adverse prognostic indicator (hazard ratio = 2.2, 95% confidence interval: 1.2-4.1, p < 0.01). In the same patient series, PD-L1 expression was also associated with downregulation of microRNAs previously shown to have tumor suppressor activity in MPM. The median microRNA expression levels of miR-15b, miR-16, miR-193a-3p, miR-195, and miR-200c were significantly lower in the PD-L1-positive samples. Transfecting MPM cell lines with mimics corresponding to miR-15a and miR-16, both of which are predicted to target PD-L1, led to downregulation of PD-L1 mRNA and protein. In addition, miR-193a-3p, with an alternative G-U-containing target site, also caused PD-L1 downregulation. CONCLUSIONS: Together, these data suggest that tumor suppressor microRNAs contribute to the regulation of PD-L1 expression in MPM.

Circulating activin A is a novel prognostic biomarker in malignant pleural mesothelioma - A multi-institutional study.

INTRODUCTION: The deregulation of activin expression is often observed in various malignancies. Previous studies indicate that activin A plays a protumourigenic role in malignant pleural mesothelioma (MPM). The aim of the study was to evaluate circulating activin A level as a biomarker in MPM. METHODS: Plasma samples were collected from 129 MPM patients in four institutions at the time of diagnosis or before surgical resection. Samples from 45 healthy individuals and from 16 patients with non-malignant pleural diseases served as controls. Circulating activin A was measured by enzyme-linked immunosorbent assay and correlated to clinicopathological variables. RESULTS: Plasma activin A level was significantly elevated in MPM patients (862 ± 83 pg/ml) when compared to healthy controls (391 ± 21 pg/ml; P < 0.0001). Patients with pleuritis or fibrosis only showed a modest increase (versus controls; 625 ± 95 pg/ml; P = 0.0067). Sarcomatoid (n = 10, 1629 ± 202 pg/ml, P = 0.0019) and biphasic (n = 23, 1164 ± 233 pg/ml, P = 0.0188) morphology were associated with high activin A levels when compared to epithelioid histology (n = 94, 712 ± 75 pg/ml). The tumour volume showed a positive correlation with increased circulating activin A levels. MPM patients with below median activin A levels had a significantly longer overall survival when compared to those with high activin A levels (median survival 735 versus 365 d, P < 0.0001). Importantly, circulating activin A levels were exclusively prognostic in epithelioid MPM. CONCLUSIONS: Our findings suggest that the measurement of circulating activin A may support the histological classification of MPM and at the same time help to identify epithelioid MPM patients with poor prognosis.

Clinical development of TargomiRs, a miRNA mimic-based treatment for patients with recurrent thoracic cancer.

miRNAs are responsible for post-transcriptional control of gene expression, and are frequently downregulated in cancer. It has become well established that restoring miRNA levels can inhibit tumor growth, and many studies have demonstrated this in preclinical models. This in turn has led to the first clinical trials of miRNA replacement therapy. This special report focuses on the development of TargomiRs - miRNA mimics delivered by targeted bacterial minicells - and the very first clinical experience of a miRNA replacement therapy in thoracic cancer patients in the Phase I MesomiR-1 trial.

The Role of Tumor-Infiltrating Lymphocytes in Development, Progression, and Prognosis of Non-Small Cell Lung Cancer.

A malignant tumor is not merely an accumulation of neoplastic cells, but constitutes a microenvironment containing endothelial cells, fibroblasts, structural components, and infiltrating immune cells that impact tumor development, invasion, metastasis, and outcome. Hence, the evolution of cancers reflects intricate cellular and molecular interactions between tumor cells and constituents of the tumor microenvironment. Recent studies have shed new light on this complex interaction between tumor and host immune cells and the resulting immune response. The composition of the immune microenvironment differs across patients as well as in cancers of the same type, including various populations of T cells, B cells, dendritic cells, natural killer cells, myeloid-derived suppressor cells, neutrophils, and macrophages. The type, density, location, and organization of immune cells within solid tumors define the immune contexture, which has proved to be a major determinant of tumor characteristics and patient outcome. Lung cancer consists mostly of non-small cell lung cancer (85%); it is our most deadly malignant disease, with the 5-year survival rate being merely 15%. This review focuses on the immune contexture; the tumor-suppressing roles of tumor-infiltrating lymphocytes; and the relevance of this immune contexture for cancer diagnostics, prognostication, and treatment allocation, with an emphasis on non-small cell lung cancer.

A proteomics-based approach identifies secreted protein acidic and rich in cysteine as a prognostic biomarker in malignant pleural mesothelioma.

BACKGROUND: We aimed to identify prognostic blood biomarkers using proteomics-based approaches in malignant pleural mesothelioma (MPM). METHODS: Plasma samples from 12 MPM patients were used for exploratory mass spectrometry and ELISA analyses. The significance of secreted protein acidic and rich in cysteine (SPARC) was examined in sera from a Dutch series (n=97). To determine the source of the circulating SPARC, we investigated SPARC expression in MPM tumours and healthy controls, as well as the expression and secretion from cell lines and xenografts. RESULTS: Secreted protein acidic and rich in cysteine was identified as a putative prognostic marker in plasma. Validation in the Dutch series showed that the median survival was higher in patients with low SPARC compared with those with high SPARC (19.0 vs 8.8 months; P=0.01). In multivariate analyses, serum SPARC remained as an independent predictor (HR 1.55; P=0.05). In MPM tumour samples, SPARC was present in the tumour cells and stromal fibroblasts. Cellular SPARC expression was higher in 5 out of 7 cell lines compared with two immortalized mesothelial lines. Neither cell lines nor xenograft tumours secreted detectable SPARC. CONCLUSIONS: Low circulating SPARC was associated with favourable prognosis. Secreted protein acidic and rich in cysteine was present in both tumour cells and stromal fibroblasts; and our in vitro and in vivo experiments suggest that stromal fibroblasts are a potential source of circulating SPARC.

Fibulin-3 levels in malignant pleural mesothelioma are associated with prognosis but not diagnosis.

BACKGROUND: Fibulin-3 (FBLN3) was recently presented as a promising novel biomarker for malignant pleural mesothelioma (MPM), warranting independent validation studies. METHODS: ELISA was used to measure cellular and secreted FBLN3 in cell lines, in plasma of xenograft tumour-bearing mice, in plasma from two independent series of MPM and non-MPM patients and in pleural fluid from a third series. Diagnostic and prognostic potential of FBLN3 was assessed by receiver operating characteristics curve analysis and Kaplan-Meier method, respectively. RESULTS: FBLN3 was expressed in all MPM and benign mesothelial cell lines tested, and a correlation was observed between cellular protein expression and secreted levels. Human FBLN3 was detectable in plasma of tumour-bearing mice, suggesting that MPM cells contribute to levels of circulating FBLN3. Plasma FBLN3 was significantly elevated in MPM patients from the Sydney cohort, but not the Vienna cohort, but the diagnostic accuracy was low (63%, (95% CI: 50.1-76.4) and 56% (95% CI: 41.5-71.0), respectively). Although FBLN3 levels in pleural effusions were not significantly different between cases and controls, FBLN3 levels in pleural effusion fluid were found to be independently associated with prognosis (hazard ratio of 9.92 (95% CI: 2.14-45.93)). CONCLUSIONS: These data confirm the potential prognostic value of pleural effusion FBLN3, but question the diagnostic value of this protein in MPM patients.