Isabelle Opitz

Functional inactivation of NF2/merlin in human mesothelioma

The tumor suppressor merlin is encoded by the neurofibromatosis type 2 gene (NF2) which is located on chromosome 22q12 and mutations in this gene have been found in 40% of mesothelioma. Mutations including deletions and insertions lead to truncated and inactivated merlin. Experimental animal models indicate that disruption of the NF2 signalling pathway, together with a deficiency in ink4a, is essential for mesothelioma development. Our hypothesis was that in human mesothelioma without detectable NF2 mutations, regulators of NF2/merlin activity such as CPI-17 would be altered. CPI-17 is an oncogene inhibiting the NF2/merlin phosphatase which is necessary to maintain NF2/merlin activity. Samples obtained from 44 mesothelioma, 3 asbestosis patients and 6 normal pleura from non-asbestos related disease patients were analyzed. Truncated NF2 transcripts or presence of isoform II only were observed in 11 mesothelioma samples. In all other mesothelioma samples only NF2 isoform I or isoforms I and II were detected. 18 mesothelioma and 1 normal pleura samples also expressed splicing variant delE2/3. Unexpected variants in addition to wild-type were identified in 24 mesothelioma samples. NF2 protein was either truncated or phosphorylated on Ser 518 in primary cultures derived from 25 tumors. CPI-17 expression was significantly increased in tumor samples without deleted NF2 compared to normal pleura and tumor expressing truncated NF2. Our results support the hypothesis that the disruption of NF2 signalling is essential for the development of human mesothelioma. In tumors where no NF2 truncation can be detected, NF2 is rendered inactive by phosphorylation of Ser 518 and this can be explained at least in part by an increased expression of CPI-17.

PTEN expression is a strong predictor of survival in mesothelioma patients

BACKGROUND Malignant pleural mesothelioma (MPM) is a highly aggressive tumour with poor prognosis and limited response to therapy. MPM is characterised by complex chromosomal aberrations, including chromosome 10 losses. The tumour suppressor gene phosphatase and tensin homologue deleted from chromosome 10 (PTEN) located on chromosome 10q23 plays an important role in different cancer, but its relevance for MPM is unclear. PATIENTS AND METHODS In the present tissue microarray-based study, 341 MPM were studied for PTEN expression by immunohistochemistry using a monoclonal mouse PTEN antibody. Expression levels were semiquantitatively scored (negative, weak, moderate, strong). Expression of PTEN was correlated to overall survival. RESULTS Clinical data from 206 patients were available. One hundred and five patients were stage T4 and 92 patients presented with regional and mediastinal lymph node metastasis. Loss of PTEN expression was observed in 62% of the cases. The survival time was correlated to PTEN expression in 126 cases with complete follow-up data. Comparing any PTEN expression versus no expression, median survival time was significantly longer (log rank test p=0.0001) in patients with PTEN expression (15.5 months; 95% CI: 3.8; 27.2 vs 9.7 months; 95% CI: 7.9; 11.7). Cox regression analysis revealed an association between PTEN expression and survival (p=0.003) independently from the histological subtype (p=0.7). CONCLUSION PTEN is an independent prognostic biomarker in mesothelioma patients. The frequent loss of expression of the tumour suppressor gene PTEN suggests involvement of the PI3K-AKT/protein kinase B (PKB) pathway in MPMs, which may be relevant for future mesothelioma treatment.

Prognostic significance of epithelial-mesenchymal transition in malignant pleural mesothelioma

BACKGROUND Epithelial-to-mesenchymal transition (EMT) is a morphologic transdifferentiation of carcinomas, conferring increased tumour invasiveness, but may also be applied to the epithelioid versus sarcomatoid histotype of malignant pleural mesothelioma (MPM). Herein, we correlated proteins of a putative MPM-EMT axis, including periostin, epidermal growth factor receptor (EGFR), integrin beta1, phosphatase and tensin homologue (PTEN), integrin-linked kinase (ILK), p21 and p27, with clinico-pathologic parameters, in particular overall survival (OS). PATIENTS AND METHODS A retrospective cohort of 352 mostly untreated patients with MPM was investigated by immunohistochemistry of a tissue microarray. Protein expression intensities were semi-quantitatively scored from 0 to 3 in their respective compartments, including peritumoural stroma as well as tumour cell plasma membrane, cytoplasm or nucleus. Data were correlated with histotype and survival outcome. RESULTS A total of 32% of the tumours were diagnosed as epithelioid, 13% as sarcomatoid and 55% as biphasic histotype. High expression of membranous EGFR and integrin beta1 as well as nuclear p27 correlated with the epithelioid and high expression of cytoplasmic tumoural and stromal periostin with the sarcomatoid histotype. The median survival time of the 128 patients with complete follow-up data was 11.7 months. Univariate survival analysis revealed age, epithelioid histotype and any therapy as prognosticators for better OS. High expression of cytoplasmic PTEN or ILK as well as high expression of nuclear p21 or p27 correlated with increased, whereas high expression of cytoplasmic periostin with decreased OS (all p values <0.05). Multivariate Cox regression revealed any treatment, low cytoplasmic periostin and high cytoplasmic PTEN as independent prognosticators for better OS. CONCLUSION Activation of periostin-triggered EMT is associated with the sarcomatoid histotype and has an impact on shorter survival of MPM patients. Finally, only the high expression of PTEN and the low expression of cytosolic periostin could be shown to be independent prognostic factors for longer OS.

Volumetry: an alternative to assess therapy response for malignant pleural mesothelioma?

The purpose of our study was to assess robustness of volumetric measurement of malignant pleural mesothelioma (MPM) before and after chemotherapy to modified RECIST (response evaluation criteria in solid tumours) criteria. 30 patients with digitally available chest computed tomography (CT) scans before and after three cycles of chemotherapy were included. Three readers independently assessed tumour response using two different methods: 1) the modified RECIST criteria; and 2) the tumour volumetric approach using dedicated software (Myrian®; Intrasense, Paris, France). Inter-rater reliability of unidimensional and volumetric measurements was assessed using intraclass correlation. Tumour response classification for modified RECIST was compared to the volumetric approach applying unidimensional RECIST volumetric equivalent criteria. The determination of unidimensional tumour measurement (RECIST) revealed a low inter-rater reliability (0.55) and a low interobserver agreement for tumour response classification (general &kgr; 0.33). Only 14 patients were classified equally. A high inter-rater reliability (0.99) and interobserver agreement (general &kgr; 0.9) were found for absolute tumour volumes (volumetric measurements). 27 cases were classified equally. The number of cases classified as “stable disease” was higher for the volumetric approach using tumour-equivalent criteria compared to modified RECIST. Volumetric measurement of MPM on CT using Myrian® software is a reliable, reproducible and sensitive method to measure tumour volume and, thus, therapy response after induction chemotherapy.

Neoadjuvant chemotherapy and extrapleural pneumonectomy of malignant pleural mesothelioma with or without hemithoracic radiotherapy (SAKK 17/04): a randomised, international, multicentre phase 2 trial

BACKGROUND Postoperative hemithoracic radiotherapy has been used to treat malignant pleural mesothelioma, but it has not been assessed in a randomised trial. We assessed high-dose hemithoracic radiotherapy after neoadjuvant chemotherapy and extrapleural pneumonectomy in patients with malignant pleural mesothelioma. METHODS We did this phase 2 trial in two parts at 14 hospitals in Switzerland, Belgium, and Germany. We enrolled patients with pathologically confirmed malignant pleural mesothelioma; resectable TNM stages T1-3 N0-2, M0; WHO performance status 0-1; age 18-70 years. In part 1, patients were given three cycles of neoadjuvant chemotherapy (cisplatin 75 mg/m(2) and pemetrexed 500 mg/m(2) on day 1 given every 3 weeks) and extrapleural pneumonectomy; the primary endpoint was complete macroscopic resection (R0-1). In part 2, participants with complete macroscopic resection were randomly assigned (1:1) to receive high-dose radiotherapy or not. The target volume for radiotherapy encompassed the entire hemithorax, the thoracotomy channel, and mediastinal nodal stations if affected by the disease or violated surgically. A boost was given to areas at high risk for locoregional relapse. The allocation was stratified by centre, histology (sarcomatoid vs epithelioid or mixed), mediastinal lymph node involvement (N0-1 vs N2), and T stage (T1-2 vs T3). The primary endpoint of part 1 was the proportion of patients achieving complete macroscopic resection (R0 and R1). The primary endpoint in part 2 was locoregional relapse-free survival, analysed by intention to treat. The trial is registered with ClinicalTrials.gov, number NCT00334594. FINDINGS We enrolled patients between Dec 7, 2005, and Oct 17, 2012. Overall, we analysed 151 patients receiving neoadjuvant chemotherapy, of whom 113 (75%) had extrapleural pneumonectomy. Median follow-up was 54·2 months (IQR 32-66). 52 (34%) of 151 patients achieved an objective response. The most common grade 3 or 4 toxic effects were neutropenia (21 [14%] of 151 patients), anaemia (11 [7%]), and nausea or vomiting (eight [5%]). 113 patients had extrapleural pneumonectomy, with complete macroscopic resection achieved in 96 (64%) of 151 patients. We enrolled 54 patients in part 2; 27 in each group. The main reasons for exclusion were patient refusal (n=20) and ineligibility (n=10). 25 of 27 patients completed radiotherapy. Median total radiotherapy dose was 55·9 Gy (IQR 46·8-56·0). Median locoregional relapse-free survival from surgery, was 7·6 months (95% CI 4·5-10·7) in the no radiotherapy group and 9·4 months (6·5-11·9) in the radiotherapy group. The most common grade 3 or higher toxic effects related to radiotherapy were nausea or vomiting (three [11%] of 27 patients), oesophagitis (two [7%]), and pneumonitis (two [7%]). One patient died of pneumonitis. We recorded no toxic effects data for the control group. INTERPRETATION Our findings do not support the routine use of hemithoracic radiotherapy for malignant pleural mesothelioma after neoadjuvant chemotherapy and extrapleural pneumonectomy. FUNDING Swiss Group for Clinical Cancer Research, Swiss State Secretariat for Education, Research and Innovation, Eli Lilly.

Role of Hedgehog Signaling in Malignant Pleural Mesothelioma

Purpose: The aim of this study was to assess the activity of hedgehog signaling pathway in malignant pleural mesothelioma (MPM). Experimental Design: The expression of hedgehog signaling components was assessed by quantitative PCR and in situ hybridization in 45 clinical samples. Primary MPM cultures were developed in serum-free condition in 3% oxygen and were used to investigate the effects of smoothened (SMO) inhibitors or GLI1 silencing on cell growth and hedgehog signaling. In vivo effects of SMO antagonists were determined in an MPM xenograft growing in nude mice. Results: A significant increase in GLI1, sonic hedgehog, and human hedgehog interacting protein gene expression was observed in MPM tumors compared with nontumoral pleural tissue. SMO antagonists inhibited GLI1 expression and cell growth in sensitive primary cultures. This effect was mimicked by GLI1 silencing. Reduced survivin and YAP protein levels were also observed. Survivin protein levels were rescued by overexpression of GLI1 or constitutively active YAP1. Treatment of tumor-bearing mice with the SMO inhibitor HhAntag led to a significant inhibition of tumor growth in vivo accompanied by decreased Ki-67 and nuclear YAP immunostaining and a significant difference in selected gene expression profile in tumors. Conclusions: An aberrant hedgehog signaling is present in MPM, and inhibition of hedgehog signaling decreases tumor growth indicating potential new therapeutic approach. Clin Cancer Res; 18(17); 4646–56. ©2012 AACR.

Autologous fibrin sealant reduces the incidence of prolonged air leak and duration of chest tube drainage after lung volume reduction surgery: a prospective randomized blinded study.

OBJECTIVE Prolonged air leak is reported in up to 50% of patients after lung volume reduction surgery. The effect of an autologous fibrin sealant on the intensity and duration of air leak and on the time to chest drain removal after lung volume reduction surgery was investigated in a randomized prospective clinical trial. METHODS Twenty-five patients underwent bilateral thoracoscopic lung volume reduction surgery. In each patient, an autologous fibrin sealant was applied along the staple lines on one side, whereas no additional measure was taken on the other side. Randomization of treatment was performed at the end of the resection on the first side. Air leak was assessed semiquantitatively by use of a severity score (0 = no leak; 4 = continuous severe leak) by two investigators blinded to the treatment. RESULT Mean value of the total severity scores for the first 48 hours postoperative was significantly lower in the treated group (4.7 +/- 7.7) than in the control group (16.0 +/- 10.1) (P < .001), independently of the length of the resection. Prolonged air leak and mean duration of drainage were also significantly reduced after application of the sealant (4.5% and 2.8 +/- 1.9 days versus 31.8% and 5.9 +/- 2.9 days) (P = .03 and P < .001). CONCLUSIONS Autologous fibrin sealant for reinforcement of the staple lines after lung volume reduction surgery significantly reduces prolonged air leak and duration of chest tube drainage.

Long-term outcomes of bilateral lobar lung transplantation

OBJECTIVES Lobar lung transplantation is an option that provides the possibility of transplanting an urgent listed recipient of small size with a size-mismatched donor lung by surgically reducing the size of the donor lung. We report our short- and long-term results with bilateral lobar lung transplantation (BLLT) and compare it with the long-term outcomes of our cohort. METHODS Retrospective analyses of 75 lung transplant recipients who received downsized lungs with a special focus on 23 recipients with BLLT performed since January 2000. Postoperative surgical complications, lung function tests, late complications and survival were analyzed. The decision to perform lobar transplantation was considered during allocation and finally decided prior to implantation. RESULTS Cystic fibrosis was the most common indication (43.5%) followed by pulmonary fibrosis (35%). Median age at transplantation was 41 (range 13-66) years. Fifteen were females. Nineteen of the transplantations (83%) were done with extracorporeal membrane oxygenation (ECMO) support; 3 of them were already on ECMO prior to transplantation. There was no 30-day or in-hospital mortality. No bronchial complications occurred. The most common early complication was haematothorax (39%), which required surgical intervention. The rate of postoperative atrial arrhythmias was 30%. Forced expiratory volumes in 1 s (% predicted) at 1 and 2 years were 76 ± 23 and 76 ± 22, respectively (mean ± standard deviation). By 2-year follow-up, bronchiolitis obliterans syndrome was documented in 3 patients with a median follow-up of 1457 days. Overall survivals at 1 and 5 years were 82 ± 8 and 64 ± 11%, respectively and were comparable with those of 219 other recipients who received bilateral lung transplantation during the same period (log rank test, P = 0.56). CONCLUSIONS This study demonstrates that BLLT has short- and long-term outcomes comparable with those of standard bilateral lung transplantation. The limitation of lung transplantation due to size-mismatch, particularly in smaller recipients, could be overcome by utilizing lobar lung transplantation.

Management of malignant pleural mesothelioma—The European experience

Management of malignant pleural mesothelioma (MPM) remains a clinical challenge and the incidence of the disease will continue to increase worldwide. Several aspects of mesothelioma treatment are discussed controversially, in particular, regarding extent and best type of surgery, radiotherapy, and the role of neoadjuvant or adjuvant treatment. However, best survival data is reported from groups using multimodality treatment including macroscopic complete resection (MCR) achieved by either extrapleural pneumonectomy (EPP) or (extended) pleurectomy/decortication for patients qualifying from the tumor biology, stage, and patients performance status and comorbidities. Several aspects have to be considered during surgery but morbidity and mortality have been reduced at experienced centres. The final analysis of extended selection algorithms is pending.

Combined Genetic and Genealogic Studies Uncover a Large BAP1 Cancer Syndrome Kindred Tracing Back Nine Generations to a Common Ancestor from the 1700s

We recently discovered an inherited cancer syndrome caused by BRCA1-Associated Protein 1 (BAP1) germline mutations, with high incidence of mesothelioma, uveal melanoma and other cancers and very high penetrance by age 55. To identify families with the BAP1 cancer syndrome, we screened patients with family histories of multiple mesotheliomas and melanomas and/or multiple cancers. We identified four families that shared an identical BAP1 mutation: they lived across the US and did not appear to be related. By combining family histories, molecular genetics, and genealogical approaches, we uncovered a BAP1 cancer syndrome kindred of ~80,000 descendants with a core of 106 individuals, whose members descend from a couple born in Germany in the early 1700s who immigrated to North America. Their descendants spread throughout the country with mutation carriers affected by multiple malignancies. Our data show that, once a proband is identified, extended analyses of these kindreds, using genomic and genealogical studies to identify the most recent common ancestor, allow investigators to uncover additional branches of the family that may carry BAP1 mutations. Using this knowledge, we have identified new branches of this family carrying BAP1 mutations. We have also implemented early-detection strategies that help identify cancers at early-stage, when they can be cured (melanomas) or are more susceptible to therapy (MM and other malignancies).