Integrative molecular characterization of malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is a highly lethal cancer of the lining of the chest cavity. To expand our understanding of MPM, we conducted a comprehensive integrated genomic study, including the most detailed analysis of BAP1 alterations to date. We identified histology-independent molecular prognostic subsets, and defined a novel genomic subtype with TP53 and SETDB1 mutations and extensive loss of heterozygosity. We also report strong expression of the immune-checkpoint gene VISTA in epithelioid MPM, strikingly higher than in other solid cancers, with implications for the immune response to MPM and for its immunotherapy. Our findings highlight new avenues for further investigation of MPM biology and novel therapeutic options. SIGNIFICANCE: Through a comprehensive integrated genomic study of 74 MPMs, we provide a deeper understanding of histology-independent determinants of aggressive behavior, define a novel genomic subtype with TP53 and SETDB1 mutations and extensive loss of heterozygosity, and discovered strong expresssion of the immune-checkpoint gene VISTA in epithelioid MPM

Molecular Characteristics of Matched Primary Non-Small-Cell Lung Carcinomas (NSCLC) and Metastases to the Brain

Background: Despite recent advances, the molecular mechanisms of brain metastasis remains poorly understood. The design of new targeted, patient-specific therapies requires knowledge of the presence of the molecular abnormalities that are present in both the primary tumor and distant metastatic sites. To determine whether the genetic profiles are constant between the primary lung cancers and their paired metastases we examined pairs of human primary and metastatic lung carcinomas by high-throughput gene mutation profiling. Design: We evaluated formalin-fixed paraffin-embedded specimens from 21 patients (11 women [52%] and 10 men [48%], median age 65 years) with NSCLC metastatic to the brain and the corresponding primary primary NSCLC and brain metastases using the Sequenom mass spectrometry-based system (iPLEX protocol - OncoMap analysis) for 252 genetic mutations in ABL1, BRAF, EGFR, FGFR3, HRAS, KIT, KRAS, MET, NRAS, PDGFRA, PI3K, and RET. Some of the lower confidence mutations identified by iPLEX protocol were validated by homogeneous mass-extend (hME) technology. Results: The results of molecular markers expression in the primary NSCLC and in metastatic brain NSCLC are summarized in table 1. In nine patients (39.1%) mutations were identified only in the primary lung tumors, in five patients (21.7%) mutations were identified only in the brain metastases, and in three patients (13%) mutations were identified in both lung and brain metastases. Except KRAS G12C mutation that was identified in two patients, all mutations identified were present in only one patient

Immunohistochemical markers associated with brain metastases in patients with nonsmall cell lung carcinoma

BACKGROUND: There are no reliable markers able to identify patients with non-small cell lung cancer (NSCLC) likely to metastasize to the brain. We investigated associations between immunohistochemical markers and development of brain metastases in patients with NSCLC. METHODS: We performed a hospital-based, case-control study of patients with newly diagnosed NSCLC between 1989 and 2003 that developed brain metastases who had available pathology material from both primary NSCLC and brain metastases. The control patients had NSCLC and no evidence of brain metastases. We examined NSCLC for expression of Ki-67, caspase-3, VEGF-A, VEGF-C, E-cadherin and EGFR in 54 surgical pathology specimens using immunohistochemistry and evaluated associations with development of brain metastases. RESULTS: Brain metastases developed after a median time of 12.5 months (range 1.7-89.4 months) from the diagnosis of NSCLC. A significantly increased risk of developing brain metastases was associated with patients who had high Ki-67 (adjusted odds ratio 12.2, 95% CI, 2.4 to 70.4, P<0.001), low caspase-3 (adjusted odds ratio 43.0, 95% CI, 5.3 to >100, P<0.001), high VEGF-C (adjusted odds ratio 14.6, 95% CI, 2.0 to >100, P<0.001), and low E-cadherin (adjusted odds ratio 3.6, 95% CI, 0.9 to 16.4, P=0.05), in the primary NSCLC. No significant risk was observed with VEGF-A and EGFR. A high Ki-67 was also associated with a shorter overall survival (P=0.04). CONCLUSIONS: Patients with NSCLC and high Ki-67, low caspase-3, high VEGF-C, and low E-cadherin in their tumors may benefit from close surveillance since they may have an increased risk of developing brain metastases

Hsp90 inhibition suppresses mutant EGFR-T790M signaling and overcomes kinase inhibitor resistance

10.1158/0008-5472.CAN-07-5428Cancer Research68145827-583

Mutation-Specific Antibodies for the Detection of EGFR Mutation in Non-Small-Cell Lung Cancer

Purpose: Activating mutations within the tyrosine kinase domain of epidermal growth factor receptor (EGFR) are found in approximately 10-20% of non-small cell lung cancer (NSCLC) patients and are associated with response to EGFR inhibitors. The most common NSCLC-associated EGFR mutations are deletions in exon 19 and L858R mutation in exon 21, together accounting for 90% of EGFR mutations. To develop a simple, sensitive, and reliable clinical assay for the identification of EGFR mutations in NSCLC patients, we generated mutation-specific rabbit monoclonal antibodies (RmAb) against each of these two most common EGFR mutations, and aimed to evaluate the detection of EGFR mutations in NSCLC patients by immunohistochemistry (IHC). Experimental Design: We tested mutation-specific antibodies by Western blot, Immunofluorescence, and immunohistochemistry. In addition, we stained 40 EGFR genotyped NSCLC tumor samples by IHC with these antibodies. Finally, with a panel of four antibodies, we screened a large set of NSCLC patient samples with unknown genotype, and confirmed the IHC results by DNA sequencing. Results: These two antibodies specifically detect the corresponding mutant form of EGFR by Western blotting, immunofluorescence, and immunohistochemistry. Screening a panel of 340 paraffin-embedded NSCLC tumor samples with these antibodies showed that the sensitivity of the IHC assay is 92%, with a specificity of 99% as compared to direct and MS-based DNA sequencing. Conclusions: This simple assay for detection of EGFR mutations in diagnostic human tissues provides a rapid, sensitive, specific and costeffective methodology to identify lung cancer patients responsive to EGFR-based therapies

Reproducibility of histopathological subtypes and invasion in pulmonary adenocarcinoma. An international interobserver study

Histological subtyping of pulmonary adenocarcinoma has recently been updated based on predominant pattern, but data on reproducibility are required for validation. This study first assesses reproducibility in subtyping adenocarcinomas and then assesses further the distinction between invasive and non-invasive (wholly lepidic) pattern of adenocarcinoma, among an international group of pulmonary pathologists. Two ring studies were performed using a micro-photographic image-based method, evaluating selected images of lung adenocarcinoma histologic patterns. In the first study, 26 pathologists reviewed representative images of typical and 'difficult' histologic patterns. A total number of scores for the typical patterns combined (n=94) and the difficult cases (n=21) were 2444 and 546, respectively. The mean kappa score (\ub1s.d.) for the five typical patterns combined and for difficult cases were 0.77\ub10.07 and 0.38\ub10.14, respectively. Although 70% of the observers identified 12-65% of typical images as single pattern, highest for solid and least for micropapillary, recognizing the predominant pattern was achieved in 92-100%, of the images except for micropapillary pattern (62%). For the second study on invasion, identified as a key problem area from the first study, 28 pathologists submitted and reviewed 64 images representing typical as well as 'difficult' examples. The kappa for typical and difficult cases was 0.55\ub10.06 and 0.08\ub10.02, respectively, with consistent subdivision by the same pathologists into invasive and non-invasive categories, due to differing interpretation of terminology defining invasion. In pulmonary adenocarcinomas with classic morphology, which comprise the majority of cases, there is good reproducibility in identifying a predominant pattern and fair reproducibility distinguishing invasive from in-situ (wholly lepidic) patterns. However, more precise definitions and better education on interpretation of existing terminology are required to improve recognition of purely in-situ disease, this being an area of increasing importance

EURACAN/IASLC Proposals for Updating the Histologic Classification of Pleural Mesothelioma: Towards a More Multidisciplinary Approach

Introduction: Molecular and immunologic breakthroughs are transforming the management of thoracic cancer, although advances have not been as marked for malignant pleural mesothelioma where pathologic diagnosis has been essentially limited to three histologic subtypes.Methods: A multidisciplinary group (pathologists, molecular biologists, surgeons, radiologists, and oncologists), sponsored by European Network for Rare Adult Solid Cancers/International Association for the Study of Lung Cancer, met in 2018 to critically review the current classification.Results: Recommendations include: (1) classification should be updated to include architectural patterns and stromal and cytologic features that refine prognostication; (2) subject to data accrual, malignant mesothelioma in situ could be an additional category; (3) grading of epithelioid malignant pleural mesotheliomas should be routinely undertaken; (4) favorable/unfavorable histologic characteristics should be routinely reported; (5) clinically relevant molecular data (programmed death ligand 1, BRCA 1 associated protein 1 [BAP1], and cyclin dependent kinase inhibitor 2A) should be incorporated into reports, if undertaken; (6) other molecular data should be accrued as part of future trials; (7) resection specimens (i.e., extended pleurectomy/decortication and extrapleural pneumonectomy) should be pathologically staged with smaller specimens being clinically staged; (8) ideally, at least three separate areas should be sampled from the pleural cavity, including areas of interest identified on pre-surgical imaging; (9) image-acquisition protocols/imaging terminology should be standardized to aid research/refine clinical staging; (10) multidisciplinary tumor boards should include pathologists to ensure appropriate treatment options are considered; (11) all histologic subtypes should be considered potential candidates for chemotherapy; (12) patients with sarcomatoid or biphasic mesothelioma should not be excluded from first-line clinical trials unless there is a compelling reason; (13) tumor subtyping should be further assessed in relation to duration of response to immunotherapy; and (14) systematic screening of all patients for germline mutations is not recommended, in the absence of a family history suspicious for BAP1 syndrome.Conclusions: These multidisciplinary recommendations for pathology classification and application will allow more informative pathologic reporting and potential risk stratification, to support clinical practice, research investigation and clinical trials. (C) 2019 International Association for the Study of Lung Cancer. Published by Elsevier Inc. All rights reserved.Pulmonolog