Dataset Information

Global DNA Methylation Analysis Identifies Two Discrete clusters of Pheochromocytoma with Distinct Genomic and Genetic Alterations.

ABSTRACT: Pheochromocytomas and paragangliomas (PPGLs) are rare and frequently heritable neural-crest derived tumours arising from the adrenal medulla or extra-adrenal chromaffin cells respectively. The majority of PPGL tumours are benign and do not recur with distant metastases. However, a sizeable fraction of these tumours secrete vasoactive catecholamines into the circulation causing a variety of symptoms including hypertension, palpitations and diaphoresis. The genetic landscape of PPGL has been well characterized and more than a dozen genes have been described as recurrently mutated. Recent studies of DNA-methylation have revealed distinct clusters of PPGL that share DNA methylation patterns and driver mutations, as well as identified potential biomarkers for malignancy. However, these findings have not been adequately validated in independent cohorts. In this study we use an array-based genome-wide approach to study the methylome of 39 PPGL and 4 normal adrenal medullae. We identified two distinct clusters of tumours characterized by different methylation patterns and different driver mutations. Moreover, we identify genes that are differentially methylated between tumour subcategories, and between tumours and normal tissue.

SUBMITTER: Backman S

PROVIDER: S-EPMC5361146 | biostudies-literature | 2017 Mar

REPOSITORIES: biostudies-literature

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Global DNA Methylation Analysis Identifies Two Discrete clusters of Pheochromocytoma with Distinct Genomic and Genetic Alterations.

Backman Samuel S Maharjan Rajani R Falk-Delgado Alberto A Crona Joakim J Cupisti Kenko K Stålberg Peter P Hellman Per P Björklund Peyman P

Scientific reports 20170322

Pheochromocytomas and paragangliomas (PPGLs) are rare and frequently heritable neural-crest derived tumours arising from the adrenal medulla or extra-adrenal chromaffin cells respectively. The majority of PPGL tumours are benign and do not recur with distant metastases. However, a sizeable fraction of these tumours secrete vasoactive catecholamines into the circulation causing a variety of symptoms including hypertension, palpitations and diaphoresis. The genetic landscape of PPGL has been well ...[more]

PMID: 28327598

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Project description:Hemangioblastomas (HBs) of the central nervous system are highly vascular neoplasms that occur sporadically or as a manifestation of von Hippel-Lindau (VHL) disease. Despite their benign nature, HBs are clinically heterogeneous and can be associated with significant morbidity due to mass effects of peritumoral cysts or tumor progression. Underlying molecular factors involved in HB tumor biology remain elusive. We investigated genome-wide DNA methylation profiles and clinical and histopathological features in a series of 47 HBs from 42 patients, including 28 individuals with VHL disease. Thirty tumors occurred in the cerebellum, 8 in the brainstem and 8 HBs were of spinal location, while 1 HB was located in the cerebrum. Histologically, 12 HBs (26%) belonged to the cellular subtype and exclusively occurred in the cerebellum, whereas 35 HBs were reticular (74%). Unsupervised clustering and dimensionality reduction of DNA methylation profiles revealed two distinct subgroups. Methylation cluster 1 comprised 30 HBs of mainly cerebellar location (29/30, 97%), whereas methylation cluster 2 contained 17 HBs predominantly located in non-cerebellar compartments (16/17, 94%). The sum of chromosomal regions being affected by copy-number alterations was significantly higher in methylation cluster 1 compared to cluster 2 (mean 262 vs. 109 Mb, p = 0.001). Of note, loss of chromosome 6 occurred in 9/30 tumors (30%) of methylation cluster 1 and was not observed in cluster 2 tumors (p = 0.01). No relevant methylation differences between sporadic and VHL-related HBs or cystic and non-cystic HBs could be detected. Deconvolution of the bulk DNA methylation profiles revealed four methylation components that were associated with the two methylation clusters suggesting cluster-specific cell-type compositions. In conclusion, methylation profiling of HBs reveals 2 distinct subgroups that mainly associate with anatomical location, cytogenetic profiles and differences in cell type composition, potentially reflecting different cells of origin.

Project description:BackgroundCDK12 genomic alterations occur in several tumor types, but little is known about their oncogenic role and clinical significance.ObjectiveTo describe the landscape of CDK12 alterations across solid cancers and the clinical features of CDK12-altered prostate cancer.Design, setting, and participantsA single-center retrospective study of 26743 patients across 25 solid tumor types who underwent tumor sequencing was performed. Clinicopathologic features and outcomes were assessed in prostate cancer.Outcome measurements and statistical analysisCDK12 alterations and their association with genomic characteristics are described. For prostate cancer patients, overall survival and time to castration resistance were assessed using univariable and multivariable Cox regression analysis.Results and limitationsCDK12 alterations were identified in 404/26743 patients (1.5%) overall, but were most frequent in prostate (100/1875, 5.3%) and ovarian cancer (43/1034, 4.2%), in which they were associated with a high prevalence of truncating variants and biallelic inactivation. CDK12 alterations defined a genomic subtype of prostate cancer with a unique copy-number alteration profile and involvement of distinct oncogenic pathway alterations, including cell-cycle pathway genes. CDK12-altered prostate cancer was associated with somewhat more aggressive clinical features and shorter overall survival (median 64.4 vs 74.9 mo; p=0.032) independent of standard clinical factors and tumor copy-number alteration burden (adjusted hazard ratio 1.80, 95% confidence interval 1.12-2.89; p=0.024). The study is limited by its retrospective nature.ConclusionsCDK12 alteration is a rare event across solid cancers but defines a clinically distinct molecular subtype of prostate cancer associated with unique genomic alterations and slightly more aggressive clinical features.Patient summaryCDK12 gene alterations occur rarely across tumor types, but more frequently in prostate cancer, where they are associated with genomic instability, cell-cycle pathway gene alterations, and somewhat worse clinical outcomes, warranting further investigation of therapeutic targeting of this disease subset.

Dataset Information

Global DNA Methylation Analysis Identifies Two Discrete clusters of Pheochromocytoma with Distinct Genomic and Genetic Alterations.

Publications

Global DNA Methylation Analysis Identifies Two Discrete clusters of Pheochromocytoma with Distinct Genomic and Genetic Alterations.

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