Project description:The clinical course of pulmonary carcinoids ranges from indolent to fatal disease, suggesting that specific molecular alterations drive progression toward the fully malignant state. A similar spectrum of clinical phenotypes occurs in pediatric neuroblastoma, in which activation of telomerase reverse transcriptase (TERT) is decisive in determining the course of disease. Genome wide DNA methylation profiling of pulmonary carcinoid tumors was used to investigate the methylation status of TERT in the context of high or low TERT expression.
Project description:High-resoution array comparative genomic hybridization of pulmonary carcinoids with a favorable and a poor disease outcome. Data set from a complementary experiment looking for differentially expressed genes is also deposited at ArrayExpress under accession ID E-MEXP-3790 (http://www.ebi.ac.uk/arrayexpress/experiments/E-MEXP-3790).
Project description:Background: It is still uncertain whether carcinoids of the lung and gastrointestinal (GI) tract have a common origin or whether they are closer in origin to carcinomas of the same organs. MicroRNA (miRNA) expression may clarify their nature and origin. Methods: First, to verify whether formalin-fixed paraffin-embedded (FFPE) samples retain the expression signature of the tissue, miRNA expression was compared between FFPE and frozen samples. Second, we selected surgically resected FFPE samples of pulmonary and GI carcinoids, as well as other types of tumors and normal tissues from each organ, and we compared the comprehensive expression patterns of miRNAs by microarray. These data were analyzed by hierarchical clustering and consensus clustering with non-negative matrix factorization (NMF). Results: The miRNA expression profiles of FFPE and frozen samples correlated quite well. In the first hierarchical clustering, most of the carcinoids formed one major cluster with loose subpartitioning into each organ type, while the second major cluster mainly comprised adenocarcinomas and normal tissues. The NMF approach largely supported hierarchical clustering. In the additional cluster analysis comparing carcinoids to small-cell lung carcinomas (SCLCs), carcinoids formed a distinct cluster, while SCLCs grouped together with pulmonary adenocarcinomas and normal lung tissues in another major cluster. Furthermore, we found some miRNAs that exhibited significant expression in carcinoids. Conclusion: Carcinoids had a characteristic pattern of miRNA expression, suggesting a common origin for pulmonary and GI carcinoids. The expression profiles were different in carcinoids and SCLCs, indicating distinct histogenesis of these neuroendocrine tumors.
Project description:Lung carcinoids (LCs) are rare and slow growing primary lung neoplasms that are understudied. Here, we performed targeted exome sequencing using a 354-cancer gene panel (n=29), mRNA sequencing (n=30) and DNA methylation assay (n=18) on macro-dissected lung carcinoids. The mutations we identified were enriched for genes involved in covalent histone modification/chromatin remodeling (34.5%) (MEN1, ARID1A, KMT2C and KMT2A were recurrently mutated) as well as DNA repair (17.2%) pathways. Unsupervised clustering and principle component analysis on gene expression and DNA methylation profiles showed 3 robust molecular subtypes (LC1, LC2, LC3) with distinct clinical features. MEN1 gene mutations were found to be enriched and exclusively in the LC2 subtype (p-value<0.001). The LC3 subtype is predominately found at endobronchial lung and earlier age of diagnosis. Immunohistochemical staining of two biomarkers, ASCL1 and S100, is sufficient to stratify the three subtypes. This molecular classification of lung carcinoids into three subtypes may help improve treatment decision and clinical management.
Project description:Our study proposes a precise mechanistic classification of clinical neuroblastoma phenotypes that is based on telomere maintenance mechanisms and RAS or p53 pathway mutations. A crucial factor in telomere maintenance is overexpression of TERT. We therefore determined a TERT expression threshold to identify MYCNWT TERTWT tumors whose TERT mRNA levels are comparable to those of tumors bearing MYCN or TERT alterations.
Project description:Although there has been increased knowledge about the molecular biology of neuroendocrine tumors (NETs), little is known about thymic carcinoids and even less about those with excessive hormone disorders, such as ectopic ACTH syndrome. This study was designed to gain insights into molecular networks underlying the tumorigenesis of thymic carcinoids with ACTH secretion. By an approach integrating cDNA microarray and methods of computational biology, we compare gene expression profile between ACTH-producing thymic carcinoids and normal thymus. Totally there are 63 biological categories increased and 108 decreased in thymic carcinoids. Cell proliferation was stimulated which may explain the relatively uncontrolled cell growth of the tumor. Dysregulation of Notch signaling pathway was likely underlying the neuroendocrine features of this type of tumors. Moreover, the inhibition of the immunity and the increased neuropeptide signaling molecules, POMC and its sorting molecule CPE, made the clinical manifestation reasonable and thus validated the array data. In conclusion, thymic carcinoids have distinguished gene expression pattern from the normal thymus and they are characterized by deregulations of a series of biofunctions, which may be involved in the development of neuroendocrine tumor. This study hence has provided not only a detailed comprehension of the molecular pathogenesis of thymic carcinoid with ectopic ACTH syndrome, but also a road map to approach thymic neuroendocrine tumors at the system level.
Project description:DNA CpG methylation profiling of LC patients samples were performed to understand genotype to phenotype corrlelations , novel molecular subtypes and cell of origins Lung carcinoids (LCs) are rare and slow growing primary lung neoplasms that are understudied. Here, we performed targeted exome sequencing using a 354-cancer gene panel (n=29), mRNA sequencing (n=30) and DNA methylation assay (n=18) on macro-dissected lung carcinoids. The mutations we identified were enriched for genes involved in covalent histone modification/chromatin remodeling (34.5%) (MEN1, ARID1A, KMT2C and KMT2A were recurrently mutated) as well as DNA repair (17.2%) pathways. Unsupervised clustering and principle component analysis on gene expression and DNA methylation profiles showed 3 robust molecular subtypes (LC1, LC2, LC3) with distinct clinical features. MEN1 gene mutations were found to be enriched and exclusively in the LC2 subtype (p-value<0.001). The LC3 subtype is predominately found at endobronchial lung and earlier age of diagnosis. Immunohistochemical staining of two biomarkers, ASCL1 and S100, is sufficient to stratify the three subtypes. This molecular classification of lung carcinoids into three subtypes may help improve treatment decision and clinical management.
Project description:Pulmonary carcinoids are rare neuroendocrine tumours of the lung. The molecular alterations underlying the pathogenesis of these tumours have not been systematically studied so far. Here we perform gene copy number analysis (n¼54), genome/exome (n¼44) and transcriptome (n¼69) sequencing of pulmonary carcinoids and observe frequent mutations in chromatin-remodelling genes. Covalent histone modifiers and subunits of the SWI/SNF complex are mutated in 40 and 22.2% of the cases, respectively, with MEN1, PSIP1 and ARID1A being recurrently affected. In contrast to small-cell lung cancer and large-cell neuroendocrine tumours, TP53 and RB1 mutations are rare events, suggesting that pulmonary carcinoids are not early progenitor lesions of the highly aggressive lung neuroendocrine tumors but arise through independent cellular mechanisms. These data also suggest that inactivation of chromatinremodelling genes is sufficient to drive transformation in pulmonary carcinoids.