| 1. |
- Lysiak, Malgorzata, et al.
(författare)
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The sex-dependent role of the androgen receptor in glioblastoma : results of molecular analyses
- 2022
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Ingår i: Molecular Oncology. - : Wiley. - 1574-7891 .- 1878-0261. ; 16:19, s. 3436-3451
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Tidskriftsartikel (refereegranskat)abstract
- We sought to analyse the androgen receptor (AR) in glioblastoma (GBM) due to the location of the AR gene on chromosome X, often reported with shorter survival and higher prevalence of GBM among males. Copy number (CN) and mRNA expression of AR were tested with droplet digital PCR in 91 fresh-frozen GBM samples and 170 formalin-fixed, paraffin-embedded samples collected at Linkoping University Hospital. The fresh-frozen cohort was also subjected to pyrosequencing methylation analysis of 17 CpG sites in the AR promoter. Additionally, the gene expression of AR was analysed in the fresh-frozen cohort and The Cancer Genome Atlas (TCGA) cohort of isocitrate dehydrogenase wild-type primary GBM (135 females and 219 males). The association of AR expression and overall survival (OS) was tested with Kaplan-Meier log rank analysis after dichotomisation by maximally selected rank statistics. We found that AR CN alterations were more common in female GBM. AR gene expression correlated with methylation levels of different CpG sites in males and females but there was no difference in expression between sexes. Survival analysis of TCGA cohort revealed the opposite effect of AR overexpression on OS of males and females, with high AR expression correlating with shorter OS in females and longer OS in males. Additional gene set enrichment analysis showed that AR expression correlated with DNA repair response, especially in the male group. In summary, we found that high AR gene expression in GBM exhibits sex-dependent effects on patient survival, which, for males, is linked to DNA repair response.
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| 2. |
- Dahlrot, R. H., et al.
(författare)
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Prognostic value of O-6-methylguanine-DNA methyltransferase (MGMT) protein expression in glioblastoma excluding nontumour cells from the analysis
- 2018
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Ingår i: Neuropathology and Applied Neurobiology. - : Wiley. - 0305-1846 .- 1365-2990. ; 44:2, s. 172-184
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Tidskriftsartikel (refereegranskat)abstract
- Aims: It is important to predict response to treatment with temozolomide (TMZ) in glioblastoma (GBM) patients. Both MGMT protein expression and MGMT promoter methylation status have been reported to predict the response to TMZ. We investigated the prognostic value of quantified MGMT protein levels in tumour cells and the prognostic importance of combining information of MGMT protein level and MGMT promoter methylation status.Methods: MGMT protein expression was quantified in tumour cells in 171 GBMs from the population‐based Region of Southern Denmark (RSD)‐cohort using a double immunofluorescence approach. Pyrosequencing was performed in 157 patients. For validation we used GBM‐patients from a Nordic Study (NS) investigating the effect of radiotherapy and different TMZ schedules.Results: When divided at the median, patients with low expression of MGMT protein (AF‐low) had the best prognosis (HR = 1.5, P = 0.01). Similar results were observed in the subgroup of patients receiving the Stupp regimen (HR = 2.0, P = 0.001). In the NS‐cohort a trend towards superior survival (HR = 1.6, P = 0.08) was seen in patients with AF‐low. Including MGMT promoter methylation status, we found for both cohorts that patients with methylated MGMT promoter and AF‐low had the best outcome; median OS 23.1 and 20.0 months, respectively.Conclusion: Our data indicate that MGMT protein expression in tumour cells has an independent prognostic significance. Exclusion of nontumour cells contributed to a more exact analysis of tumour‐specific MGMT protein expression. This should be incorporated in future studies evaluating MGMT status before potential integration into clinical practice.
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| 3. |
- Heenkenda, Menikae Kanchena, et al.
(författare)
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Assessment of genetic and non-genetic risk factors for venous thromboembolism in glioblastoma - The predictive significance of B blood group
- 2019
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Ingår i: Thrombosis Research. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0049-3848 .- 1879-2472. ; 183, s. 136-142
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Venous thromboembolism (VTE) is a common problem among patients with glioblastoma multi-forme (GBM) and with some other cancers. Here, we evaluated genetic and non-genetic potential risk factors for VTE among GBM patients. Materials and methods: A cohort of 139 patients treated with concomitant radiotherapy and temozolomide were included in the study. Next generation sequencing and genotyping approaches were applied to assess genetic risk factors in the haemostatic system. Clinical data including surgery, reoperation as well as blood group and patient information such as age and gender were available from patient records. Logistic regression analysis was performed to asses VTE risk. Results: In the study 47 patients (34%) were diagnosed for VTE during the course of their disease. When genetic and non-genetic potential risk factors were evaluated, only B blood group was found to be significantly associated with VTE incidence (odds ratio [OR] = 6.91; confidence interval [CI] = 2.19-24.14; P = 0.001). In contrast, A and O blood groups did not correlate with VTE risk. Frontal lobe tumor location also seemed to slightly increase VTE risk compared to other brain sites (OR = 3.14; CI = 1.1-10.7) although the significance level was at borderline (P = 0.05). Current study identified B blood group as the component in non-O blood groups that is responsible for increased VTE risk. Conclusion: In conclusion, these results suggest for the first time that B blood group is predictive for VTE incidence among patients with glioblastoma, information that may be potentially valuable when selecting GBM patients who are at risk for VTE for anticoagulant prophylaxis.
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| 4. |
- Lysiak, Malgorzata, 1989-
(författare)
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Biomarkers In Brain Tumors With Focus On Glioblastoma
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The primary brain tumors, gliomas, are not very common but they are deadly. Each year in Sweden around 500 patients will be diagnosed with a glioma and unfortunately most of them will have the most aggressive type, glioblastoma (GBM). Median survival, even if treated, is poor (14-17 months). Males are diagnosed up to 60% more often than females and they often have a worse prognosis. GBM affects mainly older patients and treatment includes radiochemotherapy with temozolomide (TMZ). The only known predictive biomarker for TMZ treatment is methylation of the O6-methylguanine DNA methyltransferase (MGMT) promoter and patients with methylated MGMT have better outcomes. There is a great need for biomarkers to decipher existing sex differences and others that identify patients that will benefit from radiotherapy (RT) or TMZ despite of unmethylated MGMT. Papers I-III are focused on investigating sex differences in GBM and in Paper IV we examined the methylation-based biomarkers used in diagnostics, on patients from the Nordic trial with exceptionally good and poor survival when treated with TMZ or RT. Loss of the Y chromosome (LOY) in male’s blood cells is associated with aging and, among other diseases, with cancer. We looked at 10 genes located on chromosome Y in 105 males with GBM treated with TMZ concomitant with RT and found that they are often deleted. Detected LOY, as well as deletion of the sex determining region Y (SRY) gene were associated with shorter overall survival. Low SRY gene expression analyzed in an additional cohort of 219 samples from The Cancer Genome Atlas (TCGA) was also associated with a shorter survival.In Paper II we re-analyzed data from three cohorts to compare the frequency of MGMT methylated tumors in males and females and investigated whether sex is an important factor associated with patient’s survival. This was done in a GBM cohort from the randomized, phase 3 Nordic trial, which included patients 60 years or older, treated with standard RT (60Gy) vs. hypofractionated RT vs. TMZ given in up to six 4 weekly cycles; in a population-based cohort, treated with TMZ concomitant with RT and an excerpt of the TCGA cohort of patients treated with different modalities. In all three cohorts there was a higher fraction of MGMT methylated tumors in females and MGMT methylation was predictive of longer survival for those treated with an alkylating agent, such as TMZ.The third study investigated the androgen receptor (AR), located on chromosome X as a potential sex susceptibility factor for GBM. We found that the gene encoding for AR can be amplified or deleted in GBM, and these changes are more common in females. The AR gene expression was enhanced in GBM but did not differ between sexes. At the same time, in a separate analysis for males and females, we found that high AR expression is associated with shorter survival in females and longer survival in males Also, the methylation sites in the AR promoter that correlated with gene expression are sex specific. In Paper IV we included 59 patients from the Nordic trial, equally divided by the treatment arms and MGMT methylation status, with good prognostic factors and with long or short survival. We performed genome-wide methylation analysis and identified differentially methylated sites between those with long and short survival for the TMZ treated, MGMT methylated samples, as well as the 60Gy, MGMT unmethylated and 34Gy MGMT methylated samples. This small pilot study was unable to discern any differentially methylated sites in TMZ treated samples with unmethylated MGMT, associated with long or short survival. By using a methylation-based diagnostic classifier, we were able to detect a misclassified sample that was not a GBM. Lastly, we calculated so called ‘epigenetic age’ of the tumor tissue based on the methylation data and using three different algorithms and found that in all treatment groups short-term survivors tended to have lower epigenetic age, though these results were not significant and need verification in a larger cohort.In summary, this thesis advances our knowledge on the molecular differences between male and female GBM and the association between these alterations and patients’ survival. Our results also suggest that there are potential methylation-based biomarkers apart from the MGMT promoter methylation, that can be used to distinguish between patients with good and poor prognosis, for instance, the epigenetic age.
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| 5. |
- Lysiak, Malgorzata, et al.
(författare)
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Deletions on Chromosome Y and Downregulation of the SRY Gene in Tumor Tissue Are Associated with Worse Survival of Glioblastoma Patients
- 2021
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Ingår i: Cancers. - : MDPI. - 2072-6694. ; 13:7
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Biological causes of sex disparity seen in the prevalence of cancer, including glioblastoma (GBM), remain poorly understood. One of the considered aspects is the involvement of the sex chromosomes, especially loss of chromosome Y (LOY).METHODS: Tumors from 105 isocitrate dehydrogenase (IDH) wild type male GBM patients were tested with droplet digital PCR for copy number changes of ten genes on chromosome Y. Decreased gene expression, a proxy of gene loss, was then analyzed in 225 IDH wild type GBM derived from TCGA and overall survival in both cohorts was tested with Kaplan-Meier log-rank analysis and maximally selected rank statistics for cut-off determination.RESULTS: LOY was associated with significantly shorter overall survival (7 vs. 14.6 months, p = 0.0016), and among investigated individual genes survival correlated most prominently with loss of the sex-determining region Y gene (SRY) (10.8 vs. 14.8 months, p = 0.0031). Gene set enrichment analysis revealed that epidermal growth factor receptor, platelet-derived growth factor receptor, and MYC proto-oncogene signaling pathways are associated with low SRY expression.CONCLUSION: Our data show that deletions and reduced gene expression of chromosome Y genes, especially SRY, are associated with reduced survival of male GBM patients and connected to major susceptibility pathways of gliomagenesis.
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| 6. |
- Lysiak, Malgorzata, et al.
(författare)
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Methylation associated with long- or short-term survival in glioblastoma patients from the Nordic phase 3 trial
- 2022
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Ingår i: Frontiers in Genetics. - : Frontiers Media SA. - 1664-8021. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Patients with glioblastoma (GBM) have a poor outcome, but even among patients receiving the same therapies and with good prognostic factors, one can find those with exceptionally short and long survival. From the Nordic trial, which randomized GBM patients of 60 years or older between two radiotherapy arms (60 Gy or 34 Gy) or temozolomide (TMZ), we selected 59 with good prognostic factors. These selected GBM patients were equally distributed according to treatment and MGMT promoter methylation status but had long or short survival. Methylation profiling with the Illumina Infinium Methylation EPIC BeadChip arrays was performed and utilized for methylation-based CNS tumor classification, and pathway enrichment analysis of differentially methylated CpG sites (DMCs), as well as calculation of epigenetic age acceleration with three different algorithms, to compare the long and short survival groups. Samples identified by the classifier as non-GBM IDH wildtype were excluded. DMCs between long- and short-term survivors were found in patients with methylated MGMT promoter treated with TMZ (123,510), those with unmethylated MGMT treated with 60Gy radiotherapy (4,086), and with methylated MGMT promoter treated with 34Gy radiotherapy (39,649). Long-term survivors with methylated MGMT promoter treated with TMZ exhibited hypermethylation of the Wnt signaling and the platelet activation, signaling, and aggregation pathways. The joint analysis of radiotherapy arms revealed 319 DMCs between long- and short-term survivors with unmethylated MGMT and none for samples with methylated MGMT promoter. An analysis comparing epigenetic age acceleration between patients with long- and short-term survival across all treatment arms showed a decreased epigenetic age acceleration for the latter. We identified DMCs for both TMZ and RT-treated patients and epigenetic age acceleration as a potential prognostic marker, but further systematic analysis of larger patient cohorts is necessary for confirmation of their prognostic and/or predictive properties.
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| 7. |
- Malmström, Annika, 1957-, et al.
(författare)
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ABCB1 single-nucleotide variants and survival in patients with glioblastoma treated with radiotherapy concomitant with temozolomide
- 2020
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Ingår i: The Pharmacogenomics Journal. - : Nature Publishing Group. - 1470-269X .- 1473-1150. ; 20:2, s. 213-219
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Tidskriftsartikel (refereegranskat)abstract
- Standard treatment for glioblastoma (GBM) patients is surgery and radiochemotherapy (RCT) with temozolomide (TMZ). TMZ is a substrate for ABCB1, a transmembrane drug transporter. It has been suggested that survival for GBM patients receiving TMZ is influenced by different single-nucleotide variants (SNV) of ABCB1. We therefore examined SNV:s of ABCB1, namely 1199Gamp;gt;A, 1236Camp;gt;T, 2677Gamp;gt;T/A, and 3435Camp;gt;T and correlated to survival for GBM patients receiving RCT. In a pilot cohort (97 patients) a significant correlation to survival was found for SNV 1199Gamp;gt;A, with median OS for variant G/G patients being 18.2 months versus 11.5 months for A/G (p = 0.012). We found no correlation to survival for the other SNV:s. We then expanded the cohort to 179 patients (expanded cohort) and also included a confirmatory cohort (49 patients) focusing on SNV 1199Gamp;gt;A. Median OS for G/G versus A/G plus A/A was 15.7 and 11.5 months, respectively (p = 0.085) for the expanded cohort and 13.8 versus 16.8 months (p = 0.19) for the confirmatory. In conclusion, in patients with GBM receiving RCT with TMZ, no correlation with survival was found for the SNV:s 1236Camp;gt;T, 2677Gamp;gt;T/A, and 3435Camp;gt;T of ABCB1. Although the SNV 1199Gamp;gt;A might have some impact, a clinically significant role could not be confirmed.
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| 8. |
- Malmström, Annika, 1957-, et al.
(författare)
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Do we really know who has an MGMT methylated glioma? : results of an international survey regarding use of MGMT analyses for glioma
- 2020
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Ingår i: Neuro-Oncology Practice. - Oxford : Oxford University Press. - 2054-2577 .- 2054-2585. ; 7:1, s. 68-76
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Tidskriftsartikel (refereegranskat)abstract
- Background: Glioma O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation status informs clinical decision making. Worldwide different methods and cutoff levels are used, which can lead to discordant methylation results.Methods: We conducted an international survey to clarify which methods are regularly used and why. We also explored opinions regarding international consensus on methods and cutoff.Results: The survey had 152 respondents from 25 countries. MGMT methylation status is determined for all glioblastomas in 37% of laboratories. The most common methods are methylation-specific polymerase chain reaction (msPCR) (37%) and pyrosequencing (34%). A method is selected for simplicity (56%), cost-effectiveness (50%), and reproducibility of results (52%). For sequencing, the number of CpG sites analyzed varies from 1–3 up to more than 16. For 50% of laboratories, the company producing the kit determines which CpG sites are examined, whereas 33% select the sites themselves. Selection of cutoff is equally distributed among a cutoff defined in the literature, by the local laboratory, or by the outside laboratory performing the analysis. This cutoff varies, reported from 1% to 30%, and in 1 laboratory tumor is determined as methylated in case of 1 methylated CpG site of 17 analyzed. Some report tumors as unmethylated or weakly vs highly methylated. An international consensus on MGMT methylation method and cutoff is warranted by 66% and 76% of respondents, respectively. The method preferred would be msPCR (45%) or pyrosequencing (42%), whereas 18% suggest next-generation sequencing.Conclusion: Although analysis of MGMT methylation status is routine, there is controversy regarding laboratory methods and cutoff level. Most respondents favor development of international consensus guidelines.
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| 9. |
- Malmström, Annika, et al.
(författare)
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Postoperative neoadjuvant temozolomide before radiotherapy versus standard radiotherapy in patients 60 years or younger with anaplastic astrocytoma or glioblastoma: a randomized trial
- 2017
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Ingår i: Acta Oncologica. - : TAYLOR & FRANCIS LTD. - 0284-186X .- 1651-226X. ; 56:12, s. 1776-1785
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: A pilot study of temozolomide (TMZ) given before radiotherapy (RT) for anaplastic astrocytoma (AA) and glioblastoma (GBM) resulted in prolonged survival compared to historical controls receiving RT alone. We therefore investigated neoadjuvant TMZ (NeoTMZ) in a randomized trial. During enrollment, concomitant and adjuvant radio-chemotherapy with TMZ became standard treatment. The trial was amended to include concurrent TMZ.Patients and methods: Patients, after surgery for GBM or AA, age 60 years and performance status (PS) 0-2, were randomized to either 2-3 cycles of TMZ, 200mg/m(2) days 1-5 every 28 days, followed by RT 60Gy in 30 fractions or RT only. Patients without progressive disease after two TMZ cycles, received the third cycle. From March 2005, TMZ 75mg/m(2) was administered daily concomitant with RT. TMZ was recommended first-line treatment at progression. Primary endpoint was overall survival and secondary safety.Results: The study closed prematurely after enrolling 144 patients, 103 with GBM and 41 with AA. Median age was 53 years (range 24-60) and 89 (62%) were male. PS was 0-1 for 133 (92%) patients, 53 (37%) had complete surgical resection and 18 (12%) biopsy. Ninety-two (64%) received TMZ concomitant with RT. Seventy-two (50%) were randomized to neoadjuvant treatment. For the overall study population survival was 20.3 months for RT and 17.7 months for NeoTMZ (p=.76), this not reaching the primary objective. For the preplanned subgroup analysis, we found that NeoTMZ AA patients had a median survival of 95.1 months compared to 35.2 months for RT (p=.022). For patients with GBM, no difference in survival was observed (p=.10). MGMT and IDH status affected outcome.Conclusions: No advantage of NeoTMZ was noted for the overall study population or subgroup of GBM, while NeoTMZ resulted in 5 years longer median survival for patients diagnosed as AA.
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| 10. |
- Mosrati, Mohamed Ali, et al.
(författare)
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TERT promoter mutations and polymorphisms as prognostic factors in primary glioblastoma
- 2015
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Ingår i: Oncotarget. - : IMPACT JOURNALS LLC. - 1949-2553. ; 6:18, s. 16663-16673
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Tidskriftsartikel (refereegranskat)abstract
- Telomerase reverse transcriptase (TERT) activity is up-regulated in several types of tumors including glioblastoma (GBM). In the present study, 128 primary glioblastoma patients were examined for single nucleotide polymorphisms of TERT in blood and in 92 cases for TERT promoter mutations in tumors. TERT promoter mutations were observed in 86% of the tumors and of these, C228T (-124 bp upstream start codon) was detected in 75% and C250T (-146 bp) in 25% of cases. TERT promoter mutations were associated with shorter overall survival (11 vs. 20 months p = 0.002 and 12 vs. 20, p = 0.04 for C228T and C250T, respectively). The minor alleles of rs2736100 and rs10069690 SNPs, located in intron 2 and the promotor regions, respectively, were associated with an increased risk of developing GBM (p = 0.004 and 0.001). GBM patients having both TERT promoter mutations and being homozygous carriers of the rs2853669 C-allele displayed significantly shorter overall survival than those with the wild type allele. The rs2853669 SNP is located in a putative Ets2 binding site in the promoter (-246 bp upstream start codon) close to the C228T and C250T mutation hot spots. Interleukin-6 (IL-6) expression regulated by TERT promoter status and polymorphism, what leads us to think that TERT and IL-6 plays a significant role in GBM, where specific SNPs increase the risk of developing GBM while the rs2853669 SNP and specific mutations in the TERT promoter of the tumor lead to shorter survival.
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| 11. |
- Roodakker, Kenney R., et al.
(författare)
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PROX1 is a novel pathway-specific prognostic biomarker for high-grade astrocytomas; results from independent glioblastoma cohorts stratified by age and IDH mutation status
- 2016
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Ingår i: Oncotarget. - : Impact Journals, LLC. - 1949-2553. ; 7:45, s. 72431-72442
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Tidskriftsartikel (refereegranskat)abstract
- PROX1 is a transcription factor with an essential role in embryonic development and determination of cell fate. In addition, PROX1 has been ascribed suppressive as well as oncogenic roles in several human cancers, including brain tumors. In this study we explored the correlation between PROX1 expression and patient survival in high-grade astrocytomas. For this purpose, we analyzed protein expression in tissue microarrays of tumor samples stratified by patient age and IDH mutation status. We initially screened 86 unselected high-grade astrocytomas, followed by 174 IDH1-R132H1 immunonegative glioblastomas derived from patients aged 60 years and older enrolled in the Nordic phase III trial of elderly patients with newly diagnosed glioblastoma. Representing the younger population of glioblastomas, we studied 80 IDH-wildtype glioblastomas from patients aged 18-60 years. There was no correlation between PROX1 protein and survival for patients with primary glioblastomas included in these cohorts. In contrast, high expression of PROX1 protein predicted shorter survival in the group of patients with IDH-mutant anaplastic astrocytomas and secondary glioblastomas. The prognostic impact of PROX1 in IDH-mutant 1p19q non-codeleted high-grade astrocytomas, as well as the negative findings in primary glioblastomas, was corroborated by gene expression data extracted from the Cancer Genome Atlas. We conclude that PROX1 is a new prognostic biomarker for 1p19q non-codeleted high-grade astrocytomas that have progressed from pre-existing lowgrade tumors and harbor IDH mutations.
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| 12. |
- Smits, Anja, et al.
(författare)
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Sex Disparities in MGMT Promoter Methylation and Survival in Glioblastoma : Further Evidence from Clinical Cohorts.
- 2021
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Ingår i: Journal of Clinical Medicine. - : MDPI. - 2077-0383. ; 10:4
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: Recent studies suggest an overrepresentation of MGMT promoter methylated tumors in females with IDHwt glioblastoma (GBM) compared to males, with a subsequent better response to alkylating treatment.METHODS: To reveal sex-bound associations that may have gone unnoticed in the original analysis, we re-analyzed two previously published clinical cohorts. One was the multicenter Nordic trial of elderly patients with GBM, randomizing patients into three different treatment arms, including 203 cases with known MGMT promoter methylation status. The other was a population-based study of 179 patients with IDHwt GBM, receiving concomittant radiotherapy and chemotherapy with temozolomide. Cohorts were stratified by sex to test the hypothesis that female sex in combination with MGMT promoter methylation constitutes a subgroup with more favorable outcome.RESULTS: There was a significantly larger proportion of MGMT promoter methylation and better outcome for female patients with MGMT promoter methylated tumors. Results were confirmed in 257 TCGA-derived IDHwt GBM with known sex and MGMT status.CONCLUSIONS: These results confirm that patient sex in combination with MGMT promoter methylation is a key determinant in GBM to be considered prior to treatment decisions. Our study also illustrates the need for stratification to identify such sex-bound associations.
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| 13. |
- Tabebi, Mouna, et al.
(författare)
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Genetic Alterations in Mitochondrial DNA Are Complementary to Nuclear DNA Mutations in Pheochromocytomas
- 2022
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Ingår i: Cancers. - : MDPI. - 2072-6694. ; 14:2
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Tidskriftsartikel (refereegranskat)abstract
- Background: Somatic mutations, copy-number variations, and genome instability of mitochondrial DNA (mtDNA) have been reported in different types of cancers and are suggested to play important roles in cancer development and metastasis. However, there is scarce information about pheochromocytomas and paragangliomas (PCCs/PGLs) formation.Material: To determine the potential roles of mtDNA alterations in sporadic PCCs/PGLs, we analyzed a panel of 26 nuclear susceptibility genes and the entire mtDNA sequence of seventy-seven human tumors, using next-generation sequencing, and compared the results with normal adrenal medulla tissues. We also performed an analysis of copy-number alterations, large mtDNA deletion, and gene and protein expression.Results: Our results revealed that 53.2% of the tumors harbor a mutation in at least one of the targeted susceptibility genes, and 16.9% harbor complementary mitochondrial mutations. More than 50% of the mitochondrial mutations were novel and predicted pathogenic, affecting mitochondrial oxidative phosphorylation. Large deletions were found in 26% of tumors, and depletion of mtDNA occurred in more than 87% of PCCs/PGLs. The reduction of the mitochondrial number was accompanied by a reduced expression of the regulators that promote mitochondrial biogenesis (PCG1α, NRF1, and TFAM). Further, P62 and LC3a gene expression suggested increased mitophagy, which is linked to mitochondrial dysfunction.Conclusion: The pathogenic role of these finding remains to be shown, but we suggest a complementarity and a potential contributing role in PCCs/PGLs tumorigenesis.
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| 14. |
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| 15. |
- Welander, Jenny, et al.
(författare)
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Activating FGFR1 mutations in sporadic pheochromocytoma
- 2018
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Ingår i: World Journal of Surgery. - : Springer. - 0364-2313 .- 1432-2323. ; 42:2, s. 482-489
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Tidskriftsartikel (refereegranskat)abstract
- Pheochromocytomas are neuroendocrine tumors of the adrenal glands that cause hypertension. More than a third of the cases are associated with hereditary mutations in a growing list of susceptibility genes, some of which are also somatically altered in sporadic pheochromocytomas. However, for the majority of sporadic pheochromocytomas, a genetic explanation is still lacking. Here we investigated the genomic landscape of sporadic pheochromocytomas with whole-exome sequencing of 16 paired tumor and normal DNA samples, and discovered on average 33 non-silent somatic mutations per tumor. One of the recurrently mutated genes was FGFR1, encoding the fibroblast growth factor receptor 1, which was recently revealed as an oncogene in pilocytic astrocytoma and childhood glioblastoma. Including a subsequent analysis of a larger cohort, activating FGFR1 mutations were detected in three of 80 sporadic pheochromocytomas (3.8%). Gene expression microarray profiling showed that these tumors clustered with NF1- RET- and HRAS-mutated pheochromocytomas, indicating activation of the MAPK and PI3K-AKT signal transduction pathways. The results advance our biological understanding of pheochromocytoma and suggest that somatic FGFR1 activation is an important event in a subset of these tumors.
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