| 1. |
- Crona, Joakim, et al.
(författare)
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Somatic Mutations and Genetic Heterogeneity at the CDKN1B Locus in Small Intestinal Neuroendocrine Tumors
- 2015
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Ingår i: Annals of Surgical Oncology. - : Springer Science and Business Media LLC. - 1068-9265 .- 1534-4681. ; 22, s. 1428-1435
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Until recently, the genetic landscape of small intestinal neuroendocrine tumors (SI-NETs) was limited to recurrent copy number alterations, most commonly a loss on chromosome 18. Intertumor heterogeneity with nonconcordant genotype in paired primary and metastatic lesions also is described, further contributing to the difficulty of unraveling the genetic enigma of SI-NETs. A recent study analyzing 55 SI-NET exomes nominated CDKN1B (p27) as a haploinsufficient tumor suppressor gene.METHODS: This study aimed to determine the frequency of CDKN1B inactivation and to investigate genotype-phenotype correlations. It investigated 362 tumors from 200 patients. All samples were resequenced for mutations in CDKN1B using automated Sanger sequencing. The expression of p27 was investigated in 12 CDKN1B mutant and nine wild type tumors.RESULTS: Some 8.5 % (17/200) of patients had tumors with pathogenic mutations in CDKN1B including 13 insertion deletions, four nonsense variants, and one stop-loss variant. All variants with available nontumoral DNA were classified as somatic. Inter- and intratumor heterogeneity at the CDKN1B locus was detected respectively in six of ten and two of ten patients. Patients with CDKN1B mutated tumors had both heterogeneous disease presentation and diverse prognosis. Expression of the p27 protein did not correlate with CDKN1B mutation status, and no differences in the clinical characteristics between CDKN1B mutated and CDKN1B wild type tumor carriers were found.CONCLUSION: This study corroborates the finding of CDKN1B as a potential haplo-insufficient tumor suppressor gene characterized by inter- and intratumor heterogeneity in SI-NETs.
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| 2. |
- Delgado, Alberto Verdugo, et al.
(författare)
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Exome Sequencing and CNV Analysis on Chromosome 18 in Small Intestinal Neuroendocrine Tumors : Ruling Out a Suspect?
- 2015
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Ingår i: Hormone and Metabolic Research. - : Georg Thieme Verlag KG. - 0018-5043 .- 1439-4286. ; 47:6, s. 452-455
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Tidskriftsartikel (refereegranskat)abstract
- The genetic background in small intestinal neuroendocrine tumors is poorly understood, but several studies have revealed numerical imbalances. Loss of one copy of chromosome 18 is the most frequent genetic aberration in this tumor type, which indirectly suggests that a driver mutation may be present in the remaining allele. The aim of this study was to evaluate the mutation status on chromosome 18 in small intestinal neuroendocrine tumors. DNAs from 7 small intestinal neuroendocrine tumors were subjected to whole exome capture, followed by next generation sequencing and high resolution SNP array followed by copy number variation analysis. Exome capture sequencing generated an average coverage of 50.6-138.2. Only 19 genes were covered less than 8X. No tumor-specific somatic mutation was identified. Genomic profiling revealed loss of chromosome 18 in 5 out of 7 small intestinal neuroendocrine tumors and a number of other aberrancies. Loss of chromosome 18 is the most frequent genetic aberration in small intestinal neuroendocrine tumors, but no evidence for eventual mutations in the remaining allele. This suggests involvement of other mechanisms than point mutations in small intestinal neuroendocrine tumors tumorigenesis.
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| 3. |
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| 4. |
- Delgado Verdugo, Alberto, et al.
(författare)
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Global DNA methylation patterns in small intestinal neuroendocrine tumors (SI-NETs)
- 2014
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Ingår i: Endocrine-Related Cancer. - 1351-0088 .- 1479-6821. ; 21:1, s. L5-L7
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Tidskriftsartikel (refereegranskat)abstract
- Small intestinal neuroendocrine tumors (SI-NETs) are rare hormone producing tumors and are often diagnosed at advanced stage. The genetic and epigenetic background of SI-NETs are poorly understood, but several reports have indicated chromosomal losses at 18.21-qter and 11q22-q23. The aim of this study was to characterize CpG DNA methylation status of primary SI-NETs and the corresponding lymph node metastases. We used the commercially available HumanMethylation27 Beadchip array (Illumina), which covers 27578 CpG sites spanning over 14495 genes, and analyzed a discovery cohort of 10 primary SI-NETs with matched metastases. Messenger- mRNA, were determined for selected genes in a 47 tumors. In comparison to the primary tumors, the metastases showed 2697 statistically significant differentially genes. Metastases were generally less methylated than primary tumors. The relative mRNA expression level of the differentially methylated genes AXL, CRMP1, FGF5, and APOBEC3C largely reflected the methylation status. MAPK4, RUNX3, TP73, CCND1, CHFR, AHRR, and Rb1 known to be hypermethylated in other cancer types, displayed overall high methylation level (β-value ≥ 0.9). Methylation (β -value >0,7) at 18q21-qter and 11q22-q23 were detected in genes SETBP1, ELAC1, MBD1, MAPK4, TCEB3C and ARVC1, MMP8, BTG4, APOA1, FAM89B, HSPB1, respectively. Furthermore unsupervised clustering of the tumors identified three distinct clusters, one with a highly malignant behavior. Our data supports involvement of CpG DNA methylation in metastatic progression of SI-NETs and this could present a possibility to identify more aggressive tumors based on DNA methylation.
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| 5. |
- Åkerström, Göran, et al.
(författare)
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A review on management discussions of small intestinal neuroendocrine tumors 'midgut carcinoids'
- 2015
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Ingår i: INTERNATIONAL JOURNAL OF ENDOCRINE ONCOLOGY. - : Future Medicine Ltd. - 2045-0869 .- 2045-0877. ; 2:2, s. 119-128
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Forskningsöversikt (refereegranskat)abstract
- European Neuroendocrine Tumor Society staging, together with the Ki67 grading system, has appeared as superior for classification of neuroendocrine tumors (NET). The management of small intestinal NET (SI-NET) has been overall controversial. Mesenteric metastases occur also with the smallest SI-NET, and the majority of patients risk to ultimately progress with liver metastases. 68Gallium (somatostatin receptor)/PET/CT has appeared as most sensitive for imaging, and fluorodeoxyglucose-PET is recommended to identify lesions with high proliferation. Our treatment policy for SINET is to initiate somatostatin analog treatment, and in order to prevent abdominal complications we recommend early intestinal resection for removal of primary tumors and clearance of lymph node metastases. Liver metastases are liberally treated by resection (or ablation), as this can efficiently palliate carcinoid syndrome-associated symptoms.
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| 6. |
- Åkerström, Tobias, et al.
(författare)
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Comprehensive Re-Sequencing of Adrenal Aldosterone Producing Lesions Reveal Three Somatic Mutations near the KCNJ5 Potassium Channel Selectivity Filter.
- 2012
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Ingår i: PloS one. - : Public Library of Science (PLoS). - 1932-6203. ; 7:7
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Tidskriftsartikel (refereegranskat)abstract
- Aldosterone producing lesions are a common cause of hypertension, but genetic alterations for tumorigenesis have been unclear. Recently, either of two recurrent somatic missense mutations (G151R or L168R) was found in the potassium channel KCNJ5 gene in aldosterone producing adenomas. These mutations alter the channel selectivity filter and result in Na(+) conductance and cell depolarization, stimulating aldosterone production and cell proliferation. Because a similar mutation occurs in a Mendelian form of primary aldosteronism, these mutations appear to be sufficient for cell proliferation and aldosterone production. The prevalence and spectrum of KCNJ5 mutations in different entities of adrenocortical lesions remain to be defined.
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