Malignant cells from pleural fluids in malignant mesothelioma patients reveal novel mutations.

OBJECTIVES: Malignant mesothelioma (MM) is an asbestos related tumour affecting cells of serosal cavities. More than 70% of MM patients develop pleural effusions which contain tumour cells, representing a readily accessible source of malignant cells for genetic analysis. Although common somatic mutations and losses have been identified in solid MM tumours, the characterization of tumour cells within pleural effusions could provide novel insights but is little studied. MATERIALS AND METHODS: DNA and RNA were extracted from cells from short term cultures of 27 human MM pleural effusion samples. Whole exome and transcriptome sequencing was performed using the Ion Torrent platform. Somatic mutations were identified using VarScan2 and SomaticSniper. Copy number alterations were identified using ExomeCNV in R. Significant copy number alterations were identified across all samples using GISTIC2.0. The association between tumour intrinsic properties and survival was analyzed using the Cox proportional hazards regression model. RESULTS: We identified BAP1, CDKN2A and NF2 alterations in the cells from MM pleural effusions at a higher frequency than what is typically seen in MM tumours from surgical series. The median mutation rate was 1.09 mutations/Mb. TRAF7 and LATS2 alterations were also identified at a high frequency (66% and 59% respectively). Novel regions of interest were identified, including alterations in FGFR3, and the regions 19p13.3, 8p23.1 and 1p36.32. CONCLUSION: Short term cultures of tumour cells from MM pleural effusions offer an accessible alternative to surgical tumour biopsies in the study of MM genomics and reveal novel mutations of interest. Pleural effusion tumour cells provide an opportunity for the monitoring of tumour dynamics, treatment response and the clonal evolution of MM tumours.

Ultra low dose CT screen-detected non-malignant incidental findings in the Western Australian Asbestos Review Programme.

BACKGROUND AND OBJECTIVE: Computed tomography (CT)-based studies of asbestos-exposed individuals report a high prevalence of lung cancer, but the utility of low dose CT (LDCT) to screen asbestos-exposed populations is not established. We aimed to describe the prevalence of indeterminate pulmonary nodules and incidental findings on chest LDCT of asbestos-exposed subjects in Western Australia. METHODS: A total of 906 subjects from the Western Australian Asbestos Review Programme underwent LDCT of the chest as part of regular annual review. An indeterminate (solid) nodule was defined as >50 mm3 and part-solid/non-solid nodules >5 mm. The presence of asbestos-related diseases was recorded with a standardized report. RESULTS: Subjects were mostly (81%) men with a median age of 70 years. Fifty-eight (6.5%) participants were current smokers, 511 (56.4%) ex-smokers and 325 (36.4%) never-smokers. One hundred and four indeterminate nodules were detected in 77 subjects (8.5%); of these, eight cases had confirmed lung cancer (0.88%). Eighty-seven subjects (9.6%) had incidental findings that required further investigation, 42 (4.6%) from lower airways inflammation. The majority of nodules were solid, 4-6 mm and more common with age. Five hundred and eighty (64%) subjects had pleural plaques, and 364 (40.2%) had evidence of interstitial lung disease. CONCLUSION: The prevalence of LDCT-detected indeterminate lung nodules in 906 individuals with significant asbestos exposure was 8.5%, lower than many other CT studies. Clinically important incidental findings were found in 9.4%, predominantly related to lower respiratory tract inflammation. LDCT appears to effectively describe asbestos-related diseases and is likely to be an acceptable modality to monitor asbestos-exposed individuals.

Immune response profiling of malignant pleural mesothelioma for diagnostic and prognostic biomarkers.

The asbestos induced cancer malignant mesothelioma (MM) is difficult to diagnose and has a poor prognosis. MM is an immunological cancer, therefore autoantibodies may be suitable biomarkers and associated with prognosis. We used Protoarray(®) microarrays to determine immune responses to 8798 antigens in 10 MM and 10 asbestos exposed controls and developed diagnostic panels using 17 antigens from this. The AUC of these panels were independently tested in these 10 MM patients and controls and in a validation group of 36 controls and 35 MM patients using luminex assays; none of the antigens identified were validated. Immune responses to RAB38 were associated with a better prognosis.

Absence of germline mutations in BAP1 in sporadic cases of malignant mesothelioma.

Malignant mesothelioma (MM) is a uniformly fatal tumour caused predominantly by exposure to asbestos. It is not known why some exposed individuals get mesothelioma and others do not. There is some epidemiological evidence of host susceptibility. BAP1 gene somatic mutations and allelic loss are common in mesothelioma and recently a BAP1 cancer syndrome was described in which affected individuals and families had an increased risk of cancer of multiple types, including MM. To determine if BAP1 mutations could underlie any of the sporadic mesothelioma cases in our cohort of patients, we performed targeted deep sequencing of the BAP1 exome on the IonTorrent Proton sequencer in 115 unrelated MM cases. No exonic germline BAP1 mutations of known functional significance were observed, further supporting the notion that sporadic germline BAP1 mutations are not relevant to the genetic susceptibility of MM.

Pleural fluid mesothelin as an adjunct to the diagnosis of pleural malignant mesothelioma.

RATIONALE: The diagnosis of pleural malignant mesothelioma (MM) by effusion cytology may be difficult and is currently controversial. Effusion mesothelin levels are increased in patients with MM but the clinical role of this test is uncertain. OBJECTIVES: To determine the clinical value of measuring mesothelin levels in pleural effusion supernatant to aid diagnosis of MM. METHODS AND MEASUREMENTS: Pleural effusion samples were collected prospectively from 1331 consecutive patients. Mesothelin levels were determined by commercial ELISA in effusions and their relationship to concurrent pathology reporting and final clinical diagnosis was determined. RESULTS: 2156 pleural effusion samples from 1331 individuals were analysed. The final clinical diagnosis was 183 MM, 436 non-MM malignancy, and 712 nonmalignant effusions. Effusion mesothelin had a sensitivity of 67% for MM at 95% specificity. Mesothelin was elevated in over 47% of MM cases in effusions obtained before definitive diagnosis of MM was established. In the setting of inconclusive effusion cytology, effusion mesothelin had a positive predictive value of 79% for MM and 94% for malignancy. CONCLUSIONS: A mesothelin-positive pleural effusion, irrespective of the identification of malignant cells, indicates the likely presence of malignancy and adds weight to the clinical rationale for further investigation to establish a malignant diagnosis.

Comparison of fibulin-3 and mesothelin as markers in malignant mesothelioma.

BACKGROUND: Pleural malignant mesothelioma (MM) is a deadly tumour predominantly associated with asbestos exposure. A reliable diagnostic and prognostic marker for MM will significantly enhance clinical care and is an area of intense research. Soluble mesothelin is the most studied and an FDA-approved biomarker for MM. A recent report showed promising results using fibulin-3 as a new diagnostic marker. The aim of this study was to compare the utility of fibulin-3 versus mesothelin, singly or in combination. METHODS: Fibulin-3 and soluble mesothelin were determined by ELISA in the plasma and pleural fluid of 153 patients presenting with a pleural effusion including 82 with MM, 36 with non-MM malignant effusions and 35 with benign effusions. Biomarker concentrations were determined in the plasma of an additional 49 cases with benign asbestos-related disease. RESULTS: Mesothelin provides better diagnostic accuracy than fibulin-3 for MM whether measured in plasma or pleural effusion: area under the curve (AUC) for plasma was 0.822 (95% CI 0.76 to 0.87) compared with 0.671 (0.61 to 0.73), respectively, and for pleural fluid AUC was 0.815 (0.74 to 0.87) compared with 0.588 (0.51 to 0.67), respectively. Effusion fibulin-3 was an independent significant prognostic factor for survival in MM patients; HR 2.08 (1.14 to 3.82), p=0.017. MM patients with effusion fibulin-3 levels below the median survived significantly longer than those with levels above the median (14.1 vs 7.9 months, p=0.012). Mesothelin and neutrophil to lymphocyte ratio were not significant prognostic markers. CONCLUSIONS: Soluble mesothelin is a superior diagnostic biomarker for MM compared with fibulin-3, whereas fibulin-3 provides superior prognostic information compared with mesothelin.

A genome-wide association study for malignant mesothelioma risk.

Malignant mesothelioma (MM) is a uniformly fatal tumour of mesothelial cells. MM is caused by exposure to asbestos however most individuals with documented asbestos exposure do not develop MM. Although MM appears to aggregate within families, the genetics of MM susceptibility is a relatively unexplored area. The aim of the current study was to identify genetic factors that contribute to MM risk. A genome-wide association analysis of 2,508,203 single nucleotide polymorphisms (SNPs) from 428 MM cases and 1269 controls from Western Australia was performed. Additional genotyping was performed on a sample of 778 asbestos-exposed Western Australian controls. Replication of the most strongly associated SNPs was undertaken in an independent case-control study of 392 asbestos-exposed cases and 367 asbestos-exposed controls from Italy. No SNPs achieved formal genome-wide statistical significance in the Western Australian study. However, suggestive results for MM risk were identified in the SDK1, CRTAM and RASGRF2 genes, and in the 2p12 chromosomal region. These findings were not replicated in the Italian study, although there was some evidence of replication in the region of SDK1. These suggestive associations will be further investigated in sequencing and functional studies.

Risk factors for respiratory symptoms in adults: the Busselton Health Study.

BACKGROUND AND OBJECTIVE: The prevalence of reported doctor-diagnosed 'asthma' increased between 1990 and 2005-2007 in Busselton, Western Australia, accompanied by increased reported cough and phlegm but not recent wheeze. Possible reasons for the increase in diagnosed asthma include environmental exposures and diagnostic transfer. The aim of this study was to relate subject characteristics and exposures to the presence of wheeze and/or current cough/phlegm in the 2005-2007 survey. METHODS: A gender- and age-stratified random sample of 2862 adults from the Busselton shire completed questionnaires regarding doctor-diagnosed asthma, respiratory symptoms and environmental exposures; and measures of anthropometry, spirometry, exhaled nitric oxide (eNO), airway hyperresponsiveness (AHR) and atopy. Associations between respiratory symptoms and subject characteristics were assessed in 2656 subjects. RESULTS: Wheeze was reported by 23% of subjects, cough/phlegm by 22% and both by 9%. The significant and independent correlates of wheeze were reflux symptoms, lung function, AHR, eNO, atopy, body mass index and smoking. The significant and independent correlates of cough/phlegm were reflux symptoms, lung function, smoking and dusty job. Subjects more likely to report only wheeze than only cough/phlegm were female, aged <40 years, atopic, had lower percentage predicted forced expiratory volume in one second (FEV1) or higher percentage predicted force vital capacity. CONCLUSIONS: A variety of risk factors was associated with wheeze or cough/phlegm or both. Increased non-allergic exposures may account for increased prevalence of reported cough and phlegm and may contribute to increased reported asthma in adults.

Cancer incidence and mortality among underground and surface goldminers in Western Australia.

BACKGROUND: In a cohort of goldminers, we estimated cancer mortality and incidence, for both surface and underground workers, and we examined the hypothesis that (underground) mining may be protective against prostate cancer. METHODS: Standardised mortality and incidence ratios (SMRs and SIRs) and 95% confidence intervals (CI) were calculated to compare cancer mortality and incidence of former goldminers with that of the general male population. Internal comparisons on duration of underground work were examined using Cox regression. RESULTS: During 52 608 person-years of follow-up among 2294 goldminers, 1922 deaths were observed. For any cancer, mortality was increased for the total group of miners (SMR=1.27, 95% CI 1.16-1.39). In the Cox models, lung cancer mortality and incidence were particularly increased among underground miners, even after adjustment for smoking. The SMR for prostate cancer suggested a lower risk for underground miners, whereas incidence of prostate cancer was significantly increased (SIR=1.31, 95% CI 1.07-1.60) among underground miners. CONCLUSION: Overall cancer mortality and incidence was higher among Western Australian goldminers compared with the general male population, particularly for underground mining. This study does not support the hypothesis that miners have a decreased risk of prostate cancer.

All-cause mortality and cancer incidence among adults exposed to blue asbestos during childhood.

BACKGROUND: There are few data on the long-term health outcomes of exposure to asbestos in childhood. This study investigated cancer and mortality of adults exposed to blue asbestos as children. METHODS: Data linkage to relevant health registries was used to identify cancers and mortality in a cohort of adults (n = 2,460) that had lived in an asbestos mining town during their childhood (<15 years). RESULTS: There were 217 (93 female) incident cancers and 218 (70 female) deaths among the cohort. Compared with the Western Australian population females had elevated mesothelioma, ovarian and brain cancers, and increased "all cause" and "all cancer" mortality. Males had elevated mesothelioma, leukemia, prostate, brain, and colorectal cancers, and excess mortality from "all causes," "all cancers," circulatory disease, diseases of the nervous system, and accidents. CONCLUSION: Exposure to blue asbestos in childhood is associated with an increased risk of cancer and mortality in adults.

Indwelling pleural catheters reduce inpatient days over pleurodesis for malignant pleural effusion.

BACKGROUND: Patients with malignant pleural effusion (MPE) have limited prognoses. They require long-lasting symptom relief with minimal hospitalization. Indwelling pleural catheters (IPCs) and talc pleurodesis are approved treatments for MPE. Establishing the implications of IPC and talc pleurodesis on subsequent hospital stay will influence patient choice of treatment. Therefore, our objective was to compare patients with MPE treated with IPC vs pleurodesis in terms of hospital bed days (from procedure to death or end of follow-up) and safety. METHODS: In this prospective, 12-month, multicenter study, patients with MPE were treated with IPC or talc pleurodesis, based on patient choice. Key end points were hospital bed days from procedure to death (total and effusion-related). Complications, including infection and protein depletion, were monitored longitudinally. RESULTS: One hundred sixty patients with MPE were recruited, and 65 required definitive fluid control; 34 chose IPCs and 31 pleurodesis. Total hospital bed days (from any causes) were significantly fewer in patients with IPCs (median, 6.5 days; interquartile range [IQR] = 3.75-13.0 vs pleurodesis, mean, 18.0; IQR, 8.0-26.0; P = .002). Effusion-related hospital bed days were significantly fewer with IPCs (median, 3.0 days; IQR, 1.8-8.3 vs pleurodesis, median, 10.0 days; IQR, 6.0-18.0; P < .001). Patients with IPCs spent significantly fewer of their remaining days of life in hospital (8.0% vs 11.2%, P < .001, χ(2) = 28.25). Fewer patients with IPCs required further pleural procedures (13.5% vs 32.3% in pleurodesis group). There was no difference in rates of pleural infection (P = .68) and protein (P = .65) or albumin loss (P = .22). More patients treated with IPC reported immediate (within 7 days) improvements in quality of life and dyspnea. CONCLUSIONS: Patients treated with IPCs required significantly fewer days in hospital and fewer additional pleural procedures than those who received pleurodesis. Safety profiles and symptom control were comparable.

Risk factors for adult-onset asthma: a 14-year longitudinal study.

BACKGROUND AND OBJECTIVES: Few longitudinal studies have examined the risk factors and natural history of adult-onset asthma. This study assessed the subject characteristics and lifestyle factors that predicted the new diagnosis of asthma in adulthood and how these factors changed over time in those who developed asthma compared with those who do not. METHODS: The study enrolled 1554 adults from the Busselton Health Study seen in 1981 and again in 1994-1995 who initially reported never having had doctor-diagnosed asthma. Questionnaire measures were used to assess doctor-diagnosed asthma, respiratory history and tobacco smoking. Height, weight and spirometric measures of lung function were measured. Atopy was assessed by skin prick tests. Logistic regression analysis was used to identify risk factors for adult-onset asthma and changes over time. RESULTS: Reported wheeze, rhinitis, chronic cough, smoking and lower levels of lung function in 1981 each predicted asthma diagnosis by 1994-1995. Neither initial skin-prick reactivity nor newly positive skin-prick tests at follow up were associated with adult-onset asthma. Those diagnosed with asthma were more likely to have new wheeze, new rhinitis, new habitual snoring, weight gain and excess decline in lung function. CONCLUSIONS: Adult-onset asthma has risk factors that are distinct from those observed in childhood asthma. The presence of upper airway symptoms including rhinitis, as well as lifestyle factors, such as smoking, predicts those at greatest risk. However, neither pre-existing atopy nor new atopy as measured by skin prick tests was associated with adult-onset asthma.

Respiratory infections and lung function in an Australian Aboriginal community.

BACKGROUND AND OBJECTIVE: To investigate the association between serological evidence of past infections with common respiratory pathogens and lung function in members of an isolated community of Aborigines from tropical coastal north-western Australia. METHODS: FEV(1) and FVC were assessed by dry bellows spirometer. Serum IgG titres to 11 common respiratory pathogens were assayed. Smoking history was assessed by questionnaire. Reciprocal positive IgG titres were taken as >or=10 for all pathogens with the exception of Legionella spp. (>or=40) and Burkholderia pseudomallei (>or=20). Linear regression analysis examined associations between titres and lung function after adjustment for age, height, gender and smoking, separately for adults (age > 17 years) and children. RESULTS: An increased total number of positive IgG titres was significantly associated with reduced FEV(1) (P = 0.01) and FEV(1)/FVC ratio (P = 0.01) suggesting the presence of airflow obstruction. This association was independent of age, gender, height, weight and smoking status. CONCLUSIONS: The burden of past respiratory infections may be an important determinant of airway function in this Aboriginal community.

Age and sex differences in malignant mesothelioma after residential exposure to blue asbestos (crocidolite).

BACKGROUND: Blue asbestos was mined and milled at Wittenoom, Western Australia, from 1943 until 1966. Various public records were used to establish a cohort of residents of the nearby township. Mine tailings were distributed throughout the town. AIMS: To report the incident number of malignant mesotheliomas that have occurred in residents of the town who did not work at the mine or mill; and to determine if female subjects are more susceptible to asbestos exposure than male subjects, and if children are more susceptible than adults. SUBJECTS AND METHODS: A total of 4,768 residents of the town of Wittenoom have been followed up in cancer and death registries. RESULTS: There were 67 cases of mesothelioma, and 64 deaths with mesothelioma to the end of 2002. The mortality rate with mesothelioma increased with increasing residence duration, time since first exposure, and estimated cumulative exposure. The mesothelioma mortality rate was consistently lower for female subjects when compared with male subjects, but the dose-response curve was steeper for female subjects. The rate was lower in those first exposed as children compared with those first exposed at > or = 15 years of age. The dose-response slope for asbestos exposure and mortality from mesothelioma was not different between those who were first exposed as children than those who were first exposed at > or = 15 years of age. CONCLUSIONS: Former residents of a crocidolite mining town have a high rate of mesothelioma. The rate is higher in male subjects and those > or = 15 years of age at first exposure, but women have a steeper dose-response curve.