| 1. |
- Apellániz-Ruiz, Maria, et al.
(författare)
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Targeted sequencing reveals low-frequency variants in EPHA genes as markers of paclitaxel-induced peripheral neuropathy.
- 2017
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Ingår i: Clinical Cancer Research. - : American Association of Cancer Research. - 1078-0432 .- 1557-3265. ; 23:5, s. 1227-1235
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: Neuropathy is the dose limiting toxicity of paclitaxel and a major cause for decreased quality of life. Genetic factors have been shown to contribute to paclitaxel neuropathy susceptibility; however, the major causes for inter-individual differences remain unexplained. In this study we identified genetic markers associated with paclitaxel-induced neuropathy through massive sequencing of candidate genes.EXPERIMENTAL DESIGN: We sequenced the coding region of 4 EPHA genes, 5 genes involved in paclitaxel pharmacokinetics and 30 Charcot-Marie-Tooth genes, in 228 cancer patients with no/low neuropathy or high grade neuropathy during paclitaxel treatment. An independent validation series included 202 paclitaxel-treated patients. Variation-/ gene-based analyses were used to compare variant frequencies among neuropathy groups and Cox regression models were used to analyze neuropathy evolution along treatment.RESULTS: Gene-based analysis identified EPHA6 as the gene most significantly associated with paclitaxel-induced neuropathy. Low frequency non-synonymous variants in EPHA6 were present exclusively in patients with high neuropathy and all affected the ligand binding domain. Accumulated dose analysis in the discovery series showed a significantly higher neuropathy risk for EPHA5/6/8 low-frequency non-synonymous variant carriers (HR=14.60, 95%CI=2.33-91.62, P=0.0042) and an independent cohort confirmed an increased neuropathy risk (HR=2.07, 95%CI=1.14-3.77, P=0.017). Combining the series gave an estimated 2.50-fold higher risk of neuropathy (95%CI=1.46-4.31; P=9.1x10(-4)).CONCLUSION: This first study sequencing EPHA genes revealed that low frequency variants in EPHA6, EPHA5 and EPHA8 contribute to the susceptibility to paclitaxel-induced neuropathy. Furthermore, EPHAs neuronal injury repair function suggests that these genes might constitute important neuropathy markers for many neurotoxic drugs.
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| 2. |
- Bausch, Birke, et al.
(författare)
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Germline NF1 mutational spectra and loss-of-heterozygosity analyses in patients with pheochromocytoma and neurofibromatosis type 1.
- 2007
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Ingår i: Journal of Clinical Endocrinology and Metabolism. - : The Endocrine Society. - 0021-972X .- 1945-7197. ; 92:7, s. 2784-92
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Neurofibromatosis type 1 (NF1) is a pheochromocytoma-associated syndrome. Because of the low prevalence of pheochromocytoma in NF1, we ascertained subjects by pheochromocytoma that also had NF1 in the hope of describing the germline NF1 mutational spectra of NF1-related pheochromocytoma.MATERIALS AND METHODS: An international registry for NF1-pheochromocytomas was established. Mutation scanning was performed using denaturing HPLC for intragenic variation and quantitative PCR for large deletions. Loss-of-heterozygosity analysis using markers in and around NF1 was performed.RESULTS: There were 37 eligible subjects (ages 14-70 yr). Of 21 patients with corresponding tumor available, 67% showed somatic loss of the nonmutated allele at the NF1 locus vs. 0 of 12 sporadic tumors (P = 0.0002). Overall, 86% of the 37 patients had exonic or splice site mutations, 14% large deletions or duplications; 79% of the mutations are novel. The cysteine-serine rich domain (CSR) was affected in 35% but the RAS GTPase activating protein domain (RGD) in only 13%. There did not appear to be an association between any clinical features, particularly pheochromocytoma presentation and severity, and NF1 mutation genotype.CONCLUSIONS: The germline NF1 mutational spectra comprise intragenic mutations and deletions in individuals with pheochromocytoma and NF1. NF1 mutations tended to cluster in the CSR over the RAS-GAP domain, suggesting that CSR plays a more prominent role in individuals with NF1-pheochromocytoma than in NF1 individuals without this tumor. Loss-of-heterozygosity of NF1 markers in NF1-related pheochromocytoma was significantly more frequent than in sporadic pheochromocytoma, providing further molecular evidence that pheochromocytoma is a true component of NF1.
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| 3. |
- Jiang, Jingjing, et al.
(författare)
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Sino-European Differences in the Genetic Landscape and Clinical Presentation of Pheochromocytoma and Paraganglioma
- 2020
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Ingår i: Journal of Clinical Endocrinology and Metabolism. - : The Endocrine Society. - 0021-972X .- 1945-7197. ; 105:10
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Tidskriftsartikel (refereegranskat)abstract
- Context: Pheochromocytomas and paragangliomas (PPGLs) are characterized by distinct genotype-phenotype relationships according to studies largely restricted to Caucasian populations.Objective: To assess for possible differences in genetic landscapes and genotype-phenotype relationships of PPGLs in Chinese versus European populations.Design: Cross-sectional study.Setting: 2 tertiary-care centers in China and 9 in Europe.Participants: Patients with pathologically confirmed diagnosis of PPGL, including 719 Chinese and 919 Europeans.Main Outcome Measures: Next-generation sequencing performed in tumor specimens with mutations confirmed by Sanger sequencing and tested in peripheral blood if available. Frequencies of mutations were examined according to tumor location and catecholamine biochemical phenotypes.Results: Among all patients, higher frequencies of HRAS, FGFR1, and EPAS1 mutations were observed in Chinese than Europeans, whereas the reverse was observed for NF1, VHL, RET, and SDHx. Among patients with apparently sporadic PPGLs, the most frequently mutated genes in Chinese were HRAS (16.5% [13.6-19.3] vs 9.8% [7.6-12.1]) and FGFR1 (9.8% [7.6-12.11 vs 2.2% [1.1-3.3]), whereas among Europeans the most frequently mutated genes were NF1 (15.9% [13.2-18.6) vs 6.6% [4.7-8.5)) and SDHx (10.7% [8.4-13.0] vs 4.2% [2.6-5.7]). Among Europeans, almost all paragangliomas lacked appreciable production of epinephrine and identified gene mutations were largely restricted to those leading to stabilization of hypoxia inducible factors. In contrast, among Chinese there was a larger proportion of epinephrine-producing paragangliomas, mostly due to HRAS and FGFR1 mutations.Conclusions: This study establishes Sino-European differences in the genetic landscape and presentation of PPGLs, including ethnic differences in genotype-phenotype relationships indicating a paradigm shift in our understanding of the biology of these tumors.
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| 4. |
- Leandro-Garcia, Luis J., et al.
(författare)
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Genome-wide association study identifies ephrin type A receptors implicated in paclitaxel induced peripheral sensory neuropathy
- 2013
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Ingår i: Journal of Medical Genetics. - : BMJ Publishing Group Ltd. - 0022-2593 .- 1468-6244. ; 50:9, s. 599-605
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Tidskriftsartikel (refereegranskat)abstract
- Background Peripheral neuropathy is the dose limiting toxicity of paclitaxel, a chemotherapeutic drug widely used to treat solid tumours. This toxicity exhibits great inter-individual variability of unknown origin. The present study aimed to identify genetic variants associated with paclitaxel induced neuropathy via a whole genome approach. less thanbrgreater than less thanbrgreater thanMethods A genome-wide association study (GWAS) was performed in 144 white European patients uniformly treated with paclitaxel/carboplatin and for whom detailed data on neuropathy was available. Per allele single nucleotide polymorphism (SNP) associations were assessed by Cox regression, modelling the cumulative dose of paclitaxel up to the development of grade 2 sensory neuropathy. less thanbrgreater than less thanbrgreater thanResults The strongest evidence of association was observed for the ephrin type A receptor 4 (EPHA4) locus (rs17348202, p=1.0x10(-6)), and EPHA6 and EPHA5 were among the top 25 and 50 hits (rs301927, p=3.4x10(-5) and rs1159057, p=6.8x10(-5)), respectively. A meta-analysis of EPHA5-rs7349683, the top marker for paclitaxel induced neuropathy in a previous GWAS (r(2)=0.79 with rs1159057), gave a hazard ratio (HR) estimate of 1.68 (p=1.4x10(-9)). Meta-analysis of the second hit of this GWAS, XKR4-rs4737264, gave a HR of 1.71 (p=3.1x10(-8)). Imputed SNPs at LIMK2 locus were also strongly associated with this toxicity (HR=2.78, p=2.0x10(-7)). less thanbrgreater than less thanbrgreater thanConclusions This study provides independent support of EPHA5-rs7349683 and XKR4-rs4737264 as the first markers of risk of paclitaxel induced neuropathy. In addition, it suggests that other EPHA genes also involved in axonal guidance and repair following neural injury, as well as LIMK2 locus, may play an important role in the development of this toxicity. The identified SNPs could form the basis for individualised paclitaxel chemotherapy.
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| 5. |
- Leandro-Garcia, Luis J., et al.
(författare)
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Regulatory Polymorphisms in beta-Tubulin IIa Are Associated with Paclitaxel-Induced Peripheral Neuropathy
- 2012
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Ingår i: Clinical Cancer Research. - : American Association for Cancer Research. - 1078-0432 .- 1557-3265. ; 18:16, s. 4441-4448
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Peripheral neuropathy is the dose-limiting toxicity of paclitaxel, a chemotherapeutic drug widely used to treat several solid tumors such as breast, lung, and ovary. The cytotoxic effect of paclitaxel is mediated through beta-tubulin binding in the cellular microtubules. In this study, we investigated the association between paclitaxel neurotoxicity risk and regulatory genetic variants in beta-tubulin genes. Experimental Design: We measured variation in gene expression of three beta-tubulin isotypes (I, IVb, and IIa) in lymphocytes from 100 healthy volunteers, sequenced the promoter region to identify polymorphisms putatively influencing gene expression and assessed the transcription rate of the identified variants using luciferase assays. To determine whether the identified regulatory polymorphisms were associated with paclitaxel neurotoxicity, we genotyped them in 214 patients treated with paclitaxel. In addition, paclitaxel-induced cytotoxicity in lymphoblastoid cell lines was compared with beta-tubulin expression as measured by Affymetrix exon array. Results: We found a 63-fold variation in beta-tubulin IIa gene (TUBB2A) mRNA content and three polymorphisms located at -101, -112, and -157 in TUBB2A promoter correlated with increased mRNA levels. The -101 and -112 variants, in total linkage disequilibrium, conferred TUBB2A increased transcription rate. Furthermore, these variants protected from paclitaxel-induced peripheral neuropathy [HR, 0.62; 95% confidence interval (CI), 0.42-0.93; P = 0.021, multivariable analysis]. In addition, an inverse correlation between TUBB2A and paclitaxel-induced apoptosis (P = 0.001) in lymphoblastoid cell lines further supported that higher TUBB2A gene expression conferred lower paclitaxel sensitivity. Conclusions: This is the first study showing that paclitaxel neuropathy risk is influenced by polymorphisms regulating the expression of a beta-tubulin gene.
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| 6. |
- Lenders, Jacques W. M., et al.
(författare)
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Genetics, diagnosis, management and future directions of research of phaeochromocytoma and paraganglioma : a position statement and consensus of the Working Group on Endocrine Hypertension of the European Society of Hypertension
- 2020
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Ingår i: Journal of Hypertension. - 0263-6352 .- 1473-5598. ; 38:8, s. 1443-1456
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Tidskriftsartikel (refereegranskat)abstract
- Phaeochromocytoma and paraganglioma (PPGL) are chromaffin cell tumours that require timely diagnosis because of their potentially serious cardiovascular and sometimes life- threatening sequelae. Tremendous progress in biochemical testing, imaging, genetics and pathophysiological understanding of the tumours has far-reaching implications for physicians dealing with hypertension and more importantly affected patients. Because hypertension is a classical clinical clue for PPGL, physicians involved in hypertension care are those who are often the first to consider this diagnosis. However, there have been profound changes in how PPGLs are discovered; this is often now based on incidental findings of adrenal or other masses during imaging and increasingly during surveillance based on rapidly emerging new hereditary causes of PPGL. We therefore address the relevant genetic causes of PPGLs and outline how genetic testing can be incorporated within clinical care. In addition to conventional imaging (computed tomography, MRI), new functional imaging approaches are evaluated. The novel knowledge of genotype-phenotype relationships, linking distinct genetic causes of disease to clinical behaviour and biochemical phenotype, provides the rationale for patient-tailored strategies for diagnosis, follow-up and surveillance. Most appropriate preoperative evaluation and preparation of patients are reviewed, as is minimally invasive surgery. Finally, we discuss risk factors for developing metastatic disease and how they may facilitate personalised follow-up. Experts from the European Society of Hypertension have prepared this position document that summarizes the current knowledge in epidemiology, genetics, diagnosis, treatment and surveillance of PPGL.
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| 7. |
- Toledo, Rodrigo A., et al.
(författare)
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Consensus Statement on next-generation-sequencing-based diagnostic testing of hereditary phaeochromocytomas and paragangliomas
- 2017
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Ingår i: Nature Reviews Endocrinology. - : NATURE PUBLISHING GROUP. - 1759-5029 .- 1759-5037. ; 13:4, s. 233-247
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Tidskriftsartikel (refereegranskat)abstract
- Phaeochromocytomas and paragangliomas (PPGLs) are neural-crest-derived tumours of the sympathetic or parasympathetic nervous system that are often inherited and are genetically heterogeneous. Genetic testing is recommended for patients with these tumours and for family members of patients with hereditary forms of PPGLs. Due to the large number of susceptibility genes implicated in the diagnosis of inherited PPGLs, next-generation sequencing (NGS) technology is ideally suited for carrying out genetic screening of these individuals. This Consensus Statement, formulated by a study group comprised of experts in the field, proposes specific recommendations for the use of diagnostic NGS in hereditary PPGLs. In brief, the study group recommends target gene panels for screening of germ line DNA, technical adaptations to address different modes of disease transmission, orthogonal validation of NGS findings, standardized classification of variant pathogenicity and uniform reporting of the findings. The use of supplementary assays, to aid in the interpretation of the results, and sequencing of tumour DNA, for identification of somatic mutations, is encouraged. In addition, the study group launches an initiative to develop a gene-centric curated database of PPGL variants, with annual re-evaluation of variants of unknown significance by an expert group for purposes of reclassification and clinical guidance.
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| 8. |
- Welander, Jenny
(författare)
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Genetic Alterations in Pheochromocytoma and Paraganglioma
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Pheochromocytomas and paragangliomas are neuroendocrine tumors that arise from neural crest-derived cells of the adrenal medulla and the extra-adrenal paraganglia. They cause hypertension due to an abnormally high production of catecholamines (mainly adrenaline and noradrenaline), with symptoms including recurrent episodes of headache, palpitations and sweating, and an increased risk of cardiovascular disease. Malignancy in the form of distant metastases occurs in 10-15% of the patients. The malignant cases are difficult to predict and cure, and have a poor prognosis. About a third of pheochromocytomas and paragangliomas are caused by hereditary mutations in a growing list of known susceptibility genes. However, the cause of the remaining, sporadic, tumors is still largely unknown. The aim of this thesis project has been to further characterize the genetic background of pheochromocytomas and paragangliomas, with a focus on the sporadic tumors.First, we investigated the role of the genes known from the familial tumors in the sporadic form of the disease. By studying mutations, copy number variations, DNA methylation and gene expression, we found that many of the known susceptibility genes harbor somatic alterations in sporadic pheochromocytomas. Particularly, we found that the NF1 gene, which plays an important role in suppressing cell growth and proliferation by regulating the RASMAPK pathway, was inactivated by mutations in more than 20% of the cases. The mutations occurred together with deletions of the normal allele and were associated with a reduced NF1 gene expression and a specific hormone profile. We also detected activating mutations in the gene EPAS1, which encodes HIF-2α, in a subset of sporadic cases. Microarray analysis of gene expression showed that several genes involved in angiogenesis and cell metabolism were upregulated in EPAS1-mutated tumors, which is in agreement with the role of HIF-2α in the cellular response to hypoxia. In order to comprehensively investigate all the known susceptibility genes in a larger patient cohort, we designed a targeted next-generation sequencing approach and could conclude that it was fast and cost-efficient for genetic testing of pheochromocytomas and paragangliomas. The results showed that about 40% of the sporadic cases had mutations in the tested genes. The majority of the mutations were somatic, but some apparently sporadic cases in fact carried germline mutations. Such knowledge of the genetic background can be of importance to facilitate early detection and correct treatment of pheochromocytomas, paragangliomas and potential co-occurring cancers, and also to identify relatives that might be at risk. By sequencing all the coding regions of the genome, the exome, we then identified recurrent activating mutations in a novel gene, in which mutations have previously only been reported in subgroups of brain tumors. The identified mutations are proposed to cause constitutive activation of the encoded receptor tyrosine kinase, resulting in the activation of downstream kinase signaling pathways that promote cell growth and proliferation.In summary, the studies increase our biological understanding of pheochromocytoma and paraganglioma, and possibly also co-occurring cancers in which the same genes and pathways are involved. Together with the findings of other scientific studies, our results may contribute to the development of future treatment options.
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