Islande : agrandir le monde, écrire les abîmes

Romancier, poète, lecteur, traducteur… et ancien bibliothécaire, Jón Kalman Stefánsson demande à l’écriture d’explorer les abîmes. Anna Svenbro s’est entretenue avec lui en compagnie de son traducteur, Éric Boury

Clinical trial: free fatty acid suppositories compared with enema as bowel preparation for flexible sigmoidoscopy.

To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked Files. This article is open access.The purpose of this trial was to evaluate the efficacy and safety of recently developed suppositories containing free fatty acids as a bowel-cleansing agent prior to flexible sigmoidoscopy and compare them with Klyx (docusate sodium/sorbitol).A controlled, non-inferiority, single-blind, randomised study on outpatients undergoing flexible sigmoidoscopy.Department of Gastroenterology, Landspitali-University Hospital and endoscopic clinic.53 outpatients undergoing flexible sigmoidoscopy.Participants were randomised to receive either free fatty acid suppositories (28) or a standard bowel preparation with Klyx enema (25). In the study group, two suppositories were administered the evening before as well as 2 h prior to the sigmoidoscopy. In the control group, Klyx enema (120 mL) was administered the evening before and repeated 2 h prior to the procedure.Quality of the bowel cleansing, height of scope insertion and safety.The mean height of scope insertion and bowel cleansing was 43 cm (SD=13.4) in the study group and 48 cm (SD=10.4) in the control group (NS). The investigating physicians were less satisfied with the bowel preparation in the study group compared with the control group with a difference of 20% (p<0.016). The amount of faeces noted in the rectum was similar in both groups with no significant difference (p<0.56). No serious side effects, toxic reaction or irritation were observed.The suppositories are well tolerated with no significant side effects. The suppositories had distinct bowel emptying effect and as effective as Klyx in rectal cleansing. Although physician's satisfaction was slightly lower, the height of scope insertion was similar.EudraCT nr.: 2010-018761-35

Genomic profiling of breast tumours in relation to BRCA abnormalities and phenotypes

To access publisher full text version of this article. Please click on the hyperlink in Additional Links fieldINTRODUCTION: Germline mutations in the BRCA1 and BRCA2 genes account for a considerable fraction of familial predisposition to breast cancer. Somatic mutations in BRCA1 and BRCA2 have not been found and the involvement of these genes in sporadic tumour development therefore remains unclear. METHODS: The study group consisted of 67 primary breast tumours with and without BRCA1 or BRCA2 abnormalities. Genomic alterations were profiled by high-resolution (~7 kbp) comparative genome hybridisation (CGH) microarrays. Tumour phenotypes were analysed by immunohistochemistry on tissue microarrays using selected biomarkers (ER, PR, HER-2, EGFR, CK5/6, CK8, CK18). RESULTS: Classification of genomic profiles through cluster analysis revealed four subgroups, three of which displayed high genomic instability indices (GII). Two of these GII-high subgroups were enriched with either BRCA1- or BRCA2-related tumours whereas the third was not BRCA-related. The BRCA1-related subgroup mostly displayed non-luminal phenotypes, of which basal-like were most prominent, whereas the other two genomic instability subgroups BRCA2- and GII-high-III (non-BRCA), were almost entirely of luminal phenotype. Analysis of genome architecture patterns revealed similarities between the BRCA1- and BRCA2 subgroups, with long deletions being prominent. This contrasts with the third instability subgroup, not BRCA-related, where small gains were more prominent. CONCLUSIONS: The results suggest that BRCA1- and BRCA2-related tumours develop largely through distinct genetic pathways in terms of the regions altered while also displaying distinct phenotypes. Importantly, we show that the development of a subset of sporadic tumours is similar to that of either familial BRCA1- or BRCA2 tumours. Despite their differences, we observed clear similarities between the BRCA1- and BRCA2-related subgroups reflected in the type of genomic alterations acquired with deletions of long DNA segments being prominent. This suggests similarities in the mechanisms promoting genomic instability for BRCA1- and BRCA2-associated tumours, possibly relating to deficiency in DNA repair through homologous recombination. Indeed, this feature characterized both familial and sporadic tumours displaying BRCA1- or BRCA2-like spectrums of genomic alterations. The importance of these findings lies in the potential benefit from targeted therapy, through the use of agents leading to DNA double-strand breaks such as PARP inhibitors (olaparib) and cisplatin, for a much larger group of patients than the few BRCA1 and BRCA2 germline mutation carriers

CpG promoter methylation of the ALKBH3 alkylation repair gene in breast cancer.

To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked FilesDNA repair of alkylation damage is defective in various cancers. This occurs through somatically acquired inactivation of the MGMT gene in various cancer types, including breast cancers. In addition to MGMT, the two E. coli AlkB homologs ALKBH2 and ALKBH3 have also been linked to direct reversal of alkylation damage. However, it is currently unknown whether ALKBH2 or ALKBH3 are found inactivated in cancer.Methylome datasets (GSE52865, GSE20713, GSE69914), available through Omnibus, were used to determine whether ALKBH2 or ALKBH3 are found inactivated by CpG promoter methylation. TCGA dataset enabled us to then assess the impact of CpG promoter methylation on mRNA expression for both ALKBH2 and ALKBH3. DNA methylation analysis for the ALKBH3 promoter region was carried out by pyrosequencing (PyroMark Q24) in 265 primary breast tumours and 30 proximal normal breast tissue samples along with 8 breast-derived cell lines. ALKBH3 mRNA and protein expression were analysed in cell lines using RT-PCR and Western blotting, respectively. DNA alkylation damage assay was carried out in cell lines based on immunofluorescence and confocal imaging. Data on clinical parameters and survival outcomes in patients were obtained and assessed in relation to ALKBH3 promoter methylation.The ALKBH3 gene, but not ALKBH2, undergoes CpG promoter methylation and transcriptional silencing in breast cancer. We developed a quantitative alkylation DNA damage assay based on immunofluorescence and confocal imaging revealing higher levels of alkylation damage in association with epigenetic inactivation of the ALKBH3 gene (P = 0.029). In our cohort of 265 primary breast cancer, we found 72 cases showing aberrantly high CpG promoter methylation over the ALKBH3 promoter (27%; 72 out of 265). We further show that increasingly higher degree of ALKBH3 promoter methylation is associated with reduced breast-cancer specific survival times in patients. In this analysis, ALKBH3 promoter methylation at >20% CpG methylation was found to be statistically significantly associated with reduced survival (HR = 2.3; P = 0.012). By thresholding at the clinically relevant CpG methylation level (>20%), we find the incidence of ALKBH3 promoter methylation to be 5% (13 out of 265).ALKBH3 is a novel addition to the catalogue of DNA repair genes found inactivated in breast cancer. Our results underscore a link between defective alkylation repair and breast cancer which, additionally, is found in association with poor disease outcome.Icelandic Centre for Researc

Genomic and phenotypic analysis of BRCA2 mutated breast cancers reveals co-occurring changes linked to progression

To access publisher full text version of this article. Please click on the hyperlink in Additional Links field.Inherited mutations in the BRCA2 gene greatly increase the risk of developing breast cancer. Consistent with an important role for BRCA2 in error-free DNA repair, complex genomic changes are frequently observed in tumors derived from BRCA2 mutation carriers. Here, we explore the impact of DNA copy-number changes in BRCA2 tumors with respect to phenotype and clinical staging of the disease. METHODS: Breast tumors (n = 33) derived from BRCA2 999del5 mutation carriers were examined in terms of copy-number changes with high-resolution aCGH (array comparative genomic hybridization) containing 385 thousand probes (about one for each 7 kbp) and expression of phenotypic markers on TMAs (tissue microarrays). The data were examined with respect to clinical parameters including TNM staging, histologic grade, S phase, and ploidy. RESULTS: Tumors from BRCA2 carriers of luminal and basal/triple-negative phenotypes (TNPs) differ with respect to patterns of DNA copy-number changes. The basal/TNP subtype was characterized by lack of pRb (RB1) coupled with high/intense expression of p16 (CDKN2A) gene products. We found increased proportions of Ki-67-positive cells to be significantly associated with loss of the wild-type (wt) BRCA2 allele in luminal types, whereas BRCA2wt loss was less frequent in BRCA2 tumors displaying basal/TNP phenotypes. Furthermore, we show that deletions at 13q13.1, involving the BRCA2wt allele, represents a part of a larger network of co-occurring genetic changes, including deletions at 6q22.32-q22.33, 11q14.2-q24.1, and gains at 17q24.1. Importantly, copy-number changes at these BRCA2-linked networking regions coincide with those associated with advanced progression, involving the capacity to metastasize to the nodes or more-distant sites at diagnosis. CONCLUSIONS: The results presented here demonstrate divergent paths of tumor evolution in BRCA2 carriers and that deletion of the wild-type BRCA2 allele, together with co-occurring changes at 6 q, 11 q, and 17 q, are important events in progression toward advanced disease.Eimskipafelag University Minningarsjodur Bergthoru Magnusdottur and Jakobs J Bjarnasonar Gongum Saman Icelandic Cancer Research Fund SKI Icelandic Centre for Research RANNIS The University of Icelan

A DNA methylation-based definition of biologically distinct breast cancer subtypes

In cancer, epigenetic states are deregulated and thought to be of significance in cancer development and progression. We explored DNA methylation-based signatures in association with breast cancer subtypes to assess their impact on clinical presentation and patient prognosis. DNA methylation was analyzed using Infinium 450K arrays in 40 tumors and 17 normal breast samples, together with DNA copy number changes and subtype-specific markers by tissue microarrays. The identified methylation signatures were validated against a cohort of 212 tumors annotated for breast cancer subtypes by the PAM50 method (The Cancer Genome Atlas). Selected markers were pyrosequenced in an independent validation cohort of 310 tumors and analyzed with respect to survival, clinical stage and grade. The results demonstrate that DNA methylation patterns linked to the luminal-B subtype are characterized by CpG island promoter methylation events. In contrast, a large fraction of basal-like tumors are characterized by hypomethylation events occurring within the gene body. Based on these hallmark signatures, we defined two DNA methylation-based subtypes, Epi-LumB and Epi-Basal, and show that they are associated with unfavorable clinical parameters and reduced survival. Our data show that distinct mechanisms leading to changes in CpG methylation states are operative in different breast cancer subtypes. Importantly, we show that a few selected proxy markers can be used to detect the distinct DNA methylation-based subtypes thereby providing valuable information on disease prognosis

Sex Differences in Age-Related Loss of Kidney Function

Background - CKD is more prevalent in women, but more men receive kidney replacement therapy for kidney failure. This apparent contradiction is not well understood. Methods - We investigated sex differences in the loss of kidney function and whether any sex disparities could be explained by comorbidity or CKD risk factors. In the Renal Iohexol Clearance Survey (RENIS) in northern Europe, we recruited 1837 persons (53% women, aged 50–62 years) representative of the general population and without self-reported diabetes, CKD, or cardiovascular disease. Participants’ GFR was measured by plasma iohexol clearance in 2007–2009 (n=1627), 2013–2015 (n=1324), and 2018–2020 (n=1384). At each study visit, healthy persons were defined as having no major chronic diseases or risk factors for CKD. We used generalized additive mixed models to assess age- and sex-specific GFR decline rates. Results - Women had a lower GFR than men at baseline (mean [SD], 90.0 [14.0] versus 98.0 [13.7] ml/min per 1.73 m2; P2 per year in women and −1.20 (95% confidence interval [CI], −1.12 to −1.28) in men. Although the relationship between age and GFR was very close to linear in women, it was curvilinear in men, with steeper GFR slopes at older ages (nonlinear effect; P Conclusion - Among middle-aged and elderly individuals in the general population, decline in the mean GFR in women was slower than in men, independent of health status. CKD is projected to become the fifth leading cause of years of life lost in 2040. In most countries, more women than men develop CKD stage G3, which is defined as a reduced GFR, whereas more men start RRT. This apparent contradiction is poorly understood, but proposed explanations include gender disparities in access to health care and RRT, biologic differences between women and men leading to different GFR decline rates, bias in creatinine-based formulas to estimate the GFR, and overestimation of the CKD prevalence in women. In addition, sex and gender disparities in health status could cause differences in GFR loss. For example, women have a lower prevalence of myocardial infarction and a longer life expectancy than men. However, although cross-sectional population studies have found a higher mean GFR in healthy than in unhealthy persons, it is unknown whether good health is associated with preserved GFR during aging at the individual level, and whether this can explain the sex difference in CKD prevalence. Population-based longitudinal studies with repeated assessments of GFR in the same individuals are necessary to investigate the associations between sex, health status, and age-related GFR decline. The few existing studies on GFR change rates were not population based, did not investigate the association with health status, or used equations to calculate the eGFR on the basis of endogenous substances. These eGFR equations are biased by non–GFR-related factors, such as muscle mass, affecting men and women differently, particularly during aging. Measurements of GFR by an exogenous filtration marker, e.g., iohexol, avoid these methodologic problems. Accordingly, we investigated age- and sex-specific GFR decline rates in the Renal Iohexol Clearance Survey (RENIS), which is the only general population cohort with repeated measurements of GFR.The aim of the study was to report a reference range for age-related GFR decline in the general population and to investigate possible sex disparities in GFR decline rates by health status

CpG promoter hypo-methylation and up-regulation of microRNA-190b in hormone receptor-positive breast cancer

Publisher's version (útgefin grein)Estrogen receptor-positive breast cancer is subdivided into subtypes LuminalA and LuminalB, based on different expression patterns. MicroRNA-190b has been reported to be up-regulated in estrogen receptor-positive breast cancers. In this study we aimed to investigate the role of CpG promoter methylation in regulating miR-190b expression and its impact on clinical presentation and prognosis. DNA methylation analysis for the promotor of microRNA-190b was performed by pyrosequencing 549 primary breast tumors, of which 62 were carriers of the BRCA2999del5 founder mutation, 71 proximal normal breast samples and 16 breast derived cell lines. MicroRNA-190b expression was analysed in 67 primary breast tumors, 14 paired normal breast samples and 16 breast derived cell lines. Tissue microarrays (TMAs) were available for ER (n = 436), PR (n = 436), HER-2 (N = 258) and Ki67 (n = 248). MiR-190b had reduced promoter methylation in estrogen receptor-positive breast cancers (P = 1.02e–12, Median values: ER+ 24.3, ER– 38.26) and miR-190b’s expression was up-regulated in a correlative manner (P = 1.83e–06, Spearman’s rho –0.62). Through breast cancer specific survival analysis, we demonstrated that LuminalA patients exhibiting miR-190b hypo-methylation had better survival than other patients (P = 0.034, HR = 0.29, 95% CI 0.09-0.91). We, furthermore, demonstrated that miR-190b hypo-methylation occurs less frequently in ER+ tumors from BRCA2999del5 mutation carriers than in non-mutated individuals (P = 0.038, Χ2 = 4.32, n = 335). Our results suggest that upregulation of miR-190b may occur through loss of promoter DNA methylation during the development of estrogen-receptor (ER) positive breast cancers, and that miR-190b hypo-methylation leads to increased breast cancer specific survival within the LuminalA- subtype but not LuminalB.This work was funded b y Gongum Saman (EAF), The Icelandic cancer society (TG), and Icelandic Centre for Research RANNIS grant ID # 141395Peer reviewe

Comprehensive population-wide analysis of Lynch syndrome in Iceland reveals founder mutations in MSH6 and PMS2.

To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked FilesLynch syndrome, caused by germline mutations in the mismatch repair genes, is associated with increased cancer risk. Here using a large whole-genome sequencing data bank, cancer registry and colorectal tumour bank we determine the prevalence of Lynch syndrome, associated cancer risks and pathogenicity of several variants in the Icelandic population. We use colorectal cancer samples from 1,182 patients diagnosed between 2000-2009. One-hundred and thirty-two (11.2%) tumours are mismatch repair deficient per immunohistochemistry. Twenty-one (1.8%) have Lynch syndrome while 106 (9.0%) have somatic hypermethylation or mutations in the mismatch repair genes. The population prevalence of Lynch syndrome is 0.442%. We discover a translocation disrupting MLH1 and three mutations in MSH6 and PMS2 that increase endometrial, colorectal, brain and ovarian cancer risk. We find thirteen mismatch repair variants of uncertain significance that are not associated with cancer risk. We find that founder mutations in MSH6 and PMS2 prevail in Iceland unlike most other populations.Ohio State University (OSU) Comprehensive Cancer Center OSU Colorectal Cancer Research fund Obrine-Weaver Fund Pelotonia Fellowship Award deCODE genetic