Социальная политика предприятий

Материалы III Междунар. науч. конф. студентов, аспирантов и молодых ученых, Гомель, 20 мая 2010 г

Biomarkers In Brain Tumors With Focus On Glioblastoma

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.ISBN (PDF) has been added in the PDF-version.</p

Transverse arch changes in cases of ankyloglossia

1. The study confirms an association between transverse arch dimensions and severity of ankyloglossia, which reflects relationship between molar difference and free tongue. 2. Molar difference in group A (complete and severe ankyloglossia cases) has high negative values (average -4.38) which was much smaller than the data from the literature concerning many different types of occlusion. 99 3. The exact relation between transverse arch dimension and severity of ankyloglossia needs further research.Die Arbeit erforscht gegenseitige Verhältnisse zwischen der Gröβe von transversiven Zahnbogenveränderungen und Grad der Ankyloglossie. Untersucht und analysiert werden Patienten aus der Kieferorthopädischen Praxis in Toruñ (Polen), die Fälle teilt die Verfasserin in zwei Gruppen. Die Molarabweichungen in der Gruppe A (Voll- und Hartankyloglossie) erwiesen sich den Untersuchungen nach viel geringer als die der Literatur entnommenen Angaben Genaue Abhängigkeiten zwischen der Gröβe der transversiven Zahnbogenveränderungen und dem Grad der Ankyloglossie müssten noch untersucht werden

Methylation associated with long- or short-term survival in glioblastoma patients from the Nordic phase 3 trial

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.Funding Agencies|Swedish Cancer Foundation; Lions Research Fund; FORSS; LiU Cancer</p

The sex-dependent role of the androgen receptor in glioblastoma : results of molecular analyses

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.Funding Agencies|Cancerfonden; LiU Cancer at Linkoping University; ALF Grants; Region Ostergotland; Medical Research Council of Southeast Sweden (FORSS)</p

Sex Disparities in MGMT Promoter Methylation and Survival in Glioblastoma : Further Evidence from Clinical Cohorts.

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

Do we really know who has an MGMT methylated glioma? : Results of an international survey regarding use of MGMT analyses for glioma

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.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.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 1â\u80\u933 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.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

Differential DNA Methylation of MicroRNA- Encoding Genes in Psoriatic Epidermis Highlights the Wnt Pathway

Funding Agencies|Bioinformatics Core Facility; Faculty of Medicine and Health Sciences and Clinical Genomics Linkoping; Science for Life Laboratory; Department of Biomedical and Clinical Sciences; Linkoping University; Ingrid Asp Foundation; Welander Foundation; Swedish psoriasis association</p

Genetic Alterations in Mitochondrial DNA Are Complementary to Nuclear DNA Mutations in Pheochromocytomas

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.Funding: This study was supported by ALF Grants (RÖ-532021), Region Östergötland, a grant from the Medical Research Council of Southeast Sweden (FORSS) (FORSS-481781), and by a grant from LiU Cancer, Linköping University (LiU-2019).</p

Assessment of genetic and non-genetic risk factors for venous thromboembolism in glioblastoma - The predictive significance of B blood group

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.Funding Agencies|Medical Research Council of Southeast Sweden (FORSS); County Council of Region Ostergotland, Sweden</p