DNA Methylation Studies Research Articles

Critical evaluation of the reliability of DNA methylation probes on the Illumina MethylationEPIC v1.0 BeadChip microarrays

ABSTRACT DNA methylation (DNAm) plays a crucial role in a number of complex diseases. However, the reliability of DNAm levels measured using Illumina arrays varies across different probes. Previous research primarily assessed probe reliability by comparing duplicate samples between the 450k-450k or 450k-EPIC platforms, with limited investigations on Illumina EPIC v1.0 arrays. We conducted a comprehensive assessment of the EPIC v1.0 array probe reliability using 69 blood DNA samples, each measured twice, generated by the Alzheimer’s Disease Neuroimaging Initiative study. We observed higher reliability in probes with average methylation beta values of 0.2 to 0.8, and lower reliability in type I probes or those within the promoter and CpG island regions. Importantly, we found that probe reliability has significant implications in the analyses of Epigenome-wide Association Studies (EWAS). Higher reliability is associated with more consistent effect sizes in different studies, the identification of differentially methylated regions (DMRs) and methylation quantitative trait locus (mQTLs), and significant correlations with downstream gene expression. Moreover, blood DNAm measurements obtained from probes with higher reliability are more likely to show concordance with brain DNAm measurements. Our findings, which provide crucial reliability information for probes on the EPIC v1.0 array, will serve as a valuable resource for future DNAm studies.

Abstract 7009: Quantification of DNA methylation using methylation-sensitive restriction enzymes and digital PCR

Abstract DNA methylation is a common epigenetic modification, characterized by the presence of the signature 5-methylcytosine without altering the sequence of DNA. The study of DNA methylation in mammals has gained significant attention due to its broad impact on numerous biological processes and its critical role in the onset and progression of many diseases, such as cancer and aging. Consequently, there is a pressing need for a rapid and precise method to assess methylation status. Currently, most approaches for quantifying DNA methylation rely on sodium bisulfite treatment. However, such approaches do not align with the uracil DNA glycosylase PCR system. In this study, we demonstrate the application of methylation-sensitive restriction enzymes (MSRE) and digital PCR to determine the methylation status of the Ras association domain family 1 isoform A (RASSF1A) in cancer cell lines. Digital PCR enables the precise detection and absolute quantification without the reliance on reference standards. We developed a multiplex digital PCR assay that includes the target gene RASSF1A, along with two reference genes for the purpose of monitoring digestion completion and correcting DNA input. Each sample of interest was measured both before and after a MSRE digestion. To ensure the quantification accuracy, we employed the commercially available CpGenome human methylated DNA standard with a known concentration from MilliporeSigma, treating it with and without a MSRE, and subsequently performing digital PCR experiments using Roche Digital LightCycler® IVD system with a Universal nanowell plate featuring 28,000 partitions. The expected concentrations lay within the 95% confidence interval, affirming the accurate quantification achieved through digital PCR. Next, we measured the fraction of methylated alleles in various lung cancer and breast cancer cell lines, as well as in healthy human gDNA. The methylation of RASSF1A promoter in healthy human gDNA is ~0.7%, while a broad range of methylation levels was observed in cancer cell lines, ranging from ~0.7% to ~100.2%. Notably, the influence of GC bias was identified in this study. To overcome this critical challenge, we optimized the usage of several high GC enhancers. The results demonstrated that the concentration of 5-7.5% DMSO, 7.5% glycerol, and commercially available OneTaq or Q5 GC enhancers from New England Biolabs were effectively incorporated into the Roche digital PCR system, thereby enhancing the accuracy of quantification from 30% to 100%. Together, we demonstrated a remarkable approach for DNA methylation analysis using Roche digital PCR system in combination with MSREs and suitable high GC enhancers. This study suggests a promising rapid, accurate and cost-effective tool to advance research in the field. *Data on file at Roche Diagnostics, Wilmington, MA, USA Citation Format: Yu Zhao, Lindsey Cambria. Quantification of DNA methylation using methylation-sensitive restriction enzymes and digital PCR [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7009.

The Role of Epigenetics in Brain Aneurysm and Subarachnoid Hemorrhage: A Comprehensive Review.

This comprehensive review explores the emerging field of epigenetics in intracranial aneurysm (IA) and aneurysmal subarachnoid hemorrhage (aSAH). Despite recent advancements, the high mortality of aSAH needs an understanding of its underlying pathophysiology, where epigenetics plays a crucial role. This review synthesizes the current knowledge, focusing on three primary epigenetic mechanisms: DNA methylation, non-coding RNA (ncRNA), and histone modification in IA and aSAH. While DNA methylation studies are relatively limited, they suggest a significant role in the pathogenesis and prognosis of IA and aSAH, highlighting differentially methylated positions in genes presumably involved in these pathologies. However, methodological limitations, including small sample sizes and a lack of diverse population studies, temper these results. The role of ncRNAs, particularly miRNAs, has been more extensively studied, but there are still few studies focused on histone modifications. Despite methodological challenges and inconsistent findings, these studies underscore the involvement of miRNAs in key pathophysiological processes, including vascular smooth muscle regulation and the inflammatory response. This review emphasizes methodological challenges in epigenetic research, advocating for large-scale epigenome-wide association studies integrating genetic and environmental factors, along with longitudinal studies. Such research could unravel the complex mechanisms behind IA and aSAH, guiding the development of targeted therapeutic approaches.

The association of cigarette smoking with DNA methylation and gene expression in human tissue samples

Cigarette smoking adversely affects many aspects of human health, and epigenetic responses to smoking may reflect mechanisms that mediate or defend against these effects. Prior studies of smoking and DNA methylation (DNAm), typically measured in leukocytes, have identified numerous smoking-associated regions (e.g., AHRR). To identify smoking-associated DNAm features in typically inaccessible tissues, we generated array-based DNAm data for 916 tissue samples from the GTEx (Genotype-Tissue Expression) project representing 9 tissue types (lung, colon, ovary, prostate, blood, breast, testis, kidney, and muscle). We identified 6,350 smoking-associated CpGs in lung tissue (n= 212) and 2,735 in colon tissue (n= 210), most not reported previously. For all 7 other tissue types (sample sizes 38-153), no clear associations were observed (false discovery rate 0.05), but some tissues showed enrichment for smoking-associated CpGs reported previously. For 1,646 loci (in lung) and 22 (in colon), smoking was associated with both DNAm and local gene expression. For loci detected in both lung and colon (e.g., AHRR, CYP1B1, CYP1A1), top CpGs often differed between tissues, but similar clusters of hyper- or hypomethylated CpGs were observed, with hypomethylation at regulatory elements corresponding to increased expression. For lung tissue, 17 hallmark gene sets were enriched for smoking-associated CpGs, including xenobiotic- and cancer-related gene sets. At least four smoking-associated regions in lung were impacted by lung methylation quantitative trait loci (QTLs) that co-localize with genome-wide association study (GWAS) signals for lung function (FEV1/FVC), suggesting epigenetic alterations can mediate the effects of smoking on lung health. Our multi-tissue approach has identified smoking-associated regions in disease-relevant tissues, including effects that are shared across tissue types.

Strengths and limitations of reduced representation bisulfite sequencing (RRBS) in the perspective of DNA methylation analysis in fish: a case-study on rainbow trout spermatozoa.

DNA methylation in CpG dinucleotides is an important epigenetic mark in fish spermatozoa since it has been shown that some sperm methylome features are transmitted to the offspring. Reduced representation bisulfite sequencing (RRBS) is one genome-scale methods developed to assess DNA methylation at CpG sites. It allows the sequencing of a reduced fraction of the genome expected to be enriched in CpGs. The aim of this study is to characterize the extent of the CpG sites that can be identified in the RRBS-reduced sequenced fraction of rainbow trout spermatozoa, in order to evaluate the potential of RRBS for sperm DNA methylation studies. We observed that RRBS did provide a reduced amount of genomic data, the sum of the CpGs analyzed on 12 males spanning 9% of the total genomic CpGs. CpGs were only slightly enriched in the RRBS data (×1.7 times the sequenced nucleotides), the possible causes being linked to trout genome structure and sequenced fragments size. All genomic functional features were represented in our CpG dataset, with a noticeable enrichment in exons but, strikingly, not in promoters. The number of CpGs shared between biological replicates was low, but this proportion reached workable values from six biological replicates (46% of the analyzed cytosines) on. The choices that are to be made regarding fragment size selection and the options during bioinformatic data processing are discussed. In all, RRBS is a relevant first-approach method to scan the CpG DNA methylation status of spermatozoa along rainbow trout genome, although in a very reduced pattern among biological replicates.

An Epigenome-Wide Association Study of DNA Methylation and Proliferative Retinopathy over 28 Years in Type 1 Diabetes

To perform a prospective epigenome-wide association study of DNA methylation (DNAm) and 28-year proliferative diabetic retinopathy (PDR) incidence in type 1 diabetes (T1D). Prospective observational cohort study. The Pittsburgh Epidemiology of Diabetes Complications (EDC) study of childhood-onset (< 17 years) T1D. Stereoscopic fundus photographs were taken in fields 1, 2, and 4 at baseline, 2, 4, 6, 8, 16, 23, and 28 years after DNAm measurements. The photos were graded using the modified Airlie House System. In those free of PDR at baseline (n=265; mean T1D duration of 18 years at baseline), whole blood DNAm (EPIC array) at 683 597 CpGs was analyzed in Cox models for time to event. Associations between significant CpGs and clinical risk factors were assessed; genetic variants associated with DNAm were identified (methylation quantitative trait loci [meQTLs]). Mendelian randomization was used to examine evidence of causal associations between DNAm and PDR. Post hoc regional and functional analyses were performed. Proliferative diabetic retinopathy was defined as the first instance of a grade of ≥ 60 in at least 1 eye or pan-retinal photocoagulation for PDR. Follow-up time was calculated from the study visit at which DNAm data were available (baseline) until PDR incidence or censoring (December 31, 2018 or last follow-up). PDR incidence was 53% over 28-years' follow-up. Greater DNAm of cg27512687 (KIF16B) was associated with reduced PDR incidence (P=6.3×10-9; false discovery rate [FDR]: < 0.01); 113 cis-meQTLs (P<5×10-8) were identified. Mendelianrandomization analysis using the sentinel meQTL as the instrumental variable supported a potentially causal association between cg27512687 and PDR. Cg27512687 was also associated with lower pulse rate and albumin excretion rate and higher estimated glomerular filtration rate, but its association with PDR remained independently significant after adjustment for those factors. In regional analyses, DNAm of FUT4, FKBP1A, and RIN2 was also associated with PDR incidence. DNA methylation of KIF16B, FUT4, FKBP1A, and RIN2 was associated with PDR incidence, supporting roles for epigenetic regulation of iron clearance, developmental pathways, and autophagy in PDR pathogenesis. Further study of those loci may provide insight into novel targets for interventions to prevent or delay PDR in T1D. Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

The study of HMOX1 DNA methylation and gene expression and the diagnostic potential of miR-153-3p in preeclampsia.

Background: The objective was to elucidate the potential epigenetic regulatory mechanisminHMOX1 expression in preeclampsia. Materials & methods: HMOX1 promoter DNA methylation was evaluated in the placental tissue and blood of preeclamptic and normotensive pregnant women. HMOX1 and miR-153-3p gene expression were assessed in placental tissue and peripheral blood mononuclear cells (PBMCs). Related microarray datasets in the Gene Expression Omnibus database were also analyzed. Results: In placental tissue, despite HMOX1 expression downregulation, there was no significant change in HMOX1 methylation. In PBMCs, there was no significant alteration in HMOX1 expression, while hypomethylation wasobserved in blood. The miR-153-3p expressionincreased in theplacental tissue and inthePBMCs of preeclampsia. Conclusion: DNA methylation does not affect HMOX1 expression, while miR-153-3p might be a biomarker for preeclampsia.

Skewed X-chromosome inactivation drives the proportion of DNAAF6-defective airway motile cilia and variable expressivity in primary ciliary dyskinesia

BackgroundPrimary ciliary dyskinesia (PCD) is a rare airway disorder caused by defective motile cilia. Only male patients have been reported with pathogenic mutations in X-linked DNAAF6, which result in the...

SP1 Gene Methylation in Head and Neck Squamous Cell Cancer in HPV-Negative Patients.

There is still much to learn about the epigenetic mechanisms controlling gene expression during carcinogenesis. When researching aberrant DNA methylation, active proliferative tumor cells from head and neck squamous cell cancer (HNSCC) can be used as a model. The aim of the study was to investigate the methylation status of CDKN1, CDKN2A, MYC, Smad3, SP1, and UBC genes in tumor tissue (control-normal tissue) in 50 patients (37 men and 13 women) with HPV-negative HNSCC. Methods: Bisulfite conversion methods and methyl-sensitive analysis of high-resolution melting curves were used to quantify the methylation of genes. In all patients and across various subgroups (tongue carcinoma, laryngeal and other types of carcinomas T2, T3, T4 status; age before and after 50 years; smoking and non-smoking), there are consistent differences in the methylation levels in the SP1 gene in tumor DNA compared to normal. Results: The methylation of the SP1 gene in tumor DNA suppresses its expression, hinders HNSCC cell proliferation regulation, and could be a molecular indicator of malignant cell growth. The study of DNA methylation of various genes involved in carcinogenesis is promising because hypermethylated promoters can serve as potential biomarkers of disease.

Tunable DNMT1 degradation reveals DNMT1/DNMT3B synergy in DNA methylation and genome organization.

DNA methylation (DNAme) is a key epigenetic mark that regulates critical biological processes maintaining overall genome stability. Given its pleiotropic function, studies of DNAme dynamics are crucial, but currently available tools to interfere with DNAme have limitations and major cytotoxic side effects. Here, we present cell models that allow inducible and reversible DNAme modulation through DNMT1 depletion. By dynamically assessing whole genome and locus-specific effects of induced passive demethylation through cell divisions, we reveal a cooperative activity between DNMT1 and DNMT3B, but not of DNMT3A, to maintain and control DNAme. We show that gradual loss of DNAme is accompanied by progressive and reversible changes in heterochromatin, compartmentalization, and peripheral localization. DNA methylation loss coincides with a gradual reduction of cell fitness due to G1 arrest, with minor levels of mitotic failure. Altogether, this system allows DNMTs and DNA methylation studies with fine temporal resolution, which may help to reveal the etiologic link between DNAme dysfunction and human disease.

Contributions of prenatal risk factors and neonatal epigenetics to cognitive outcome in children born very preterm.

Children born less than 30 weeks gestational age (GA) are at high risk for neurodevelopmental delay compared to term peers. Prenatal risk factors and neonatal epigenetics could help identify preterm children at highest risk for poor cognitive outcomes. We aimed to understand the associations among cumulative prenatal risk, neonatal DNA methylation, and child cognitive ability at age 3 years, including whether DNA methylation mediates the association between prenatal risk and cognitive ability. We studied 379 neonates (54% male) born less than 30 weeks GA who had DNA methylation measured at neonatal intensive care unit discharge along with 3-year follow-up data. Cumulative prenatal risk was calculated from 24 risk factors obtained from maternal report and medical record and epigenome-wide neonatal DNA methylation was assayed from buccal swabs. At 3-year follow-up, child cognitive ability was assessed using the Bayley Scales of Infant and Toddler Development (third edition). Cumulative prenatal risk and DNA methylation at two cytosine-phosphate-guanines (CpGs) were uniquely associated with child cognitive ability. Using high-dimensional mediation analysis, we also identified differential methylation of 309 CpGs that mediated the association between cumulative prenatal risk and child cognitive ability. Many of the associated CpGs were located in genes (TNS3, TRAPPC4, MAD1L1, APBB2, DIP2C, TRAPPC9, DRD2) that have previously been associated with prenatal exposures and/or neurodevelopmental phenotypes. Our findings suggest a role for both prenatal risk factors and DNA methylation in explaining outcomes for children born preterm and suggest we should further study DNA methylation as a potential mechanism underlying the association between prenatal risk and child neurodevelopment. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Blood epigenome-wide association studies of suicide attempt in adults with bipolar disorder

Suicide attempt (SA) risk is elevated in individuals with bipolar disorder (BD), and DNA methylation patterns may serve as possible biomarkers of SA. We conducted epigenome-wide association studies (EWAS) of blood DNA methylation associated with BD and SA. DNA methylation was measured at >700,000 positions in a discovery cohort of n = 84 adults with BD with a history of SA (BD/SA), n = 79 adults with BD without history of SA (BD/non-SA), and n = 76 non-psychiatric controls (CON). EWAS revealed six differentially methylated positions (DMPs) and seven differentially methylated regions (DMRs) between BD/SA and BD/non-SA, with multiple immune-related genes implicated. There were no epigenome-wide significant differences when BD/SA and BD/non-SA were each compared to CON, and patterns suggested that epigenetics differentiating BD/SA from BD/non-SA do not differentiate BD/non-SA from CON. Weighted gene co-methylation network analysis and trait enrichment analysis of the BD/SA vs. BD/non-SA contrast further corroborated immune system involvement, while gene ontology analysis implicated calcium signalling. In an independent replication cohort of n = 48 BD/SA and n = 47 BD/non-SA, fold changes at the discovery cohort’s significant sites showed moderate correlation across cohorts and agreement on direction. In both cohorts, classification accuracy for SA history among individuals with BD was highest when methylation at the significant CpG sites as well as information from clinical interviews were combined, with an AUC of 88.8% (CI = 83.8–93.8%) and 82.1% (CI = 73.6–90.5%) for the combined epigenetic-clinical classifier in the discovery and replication cohorts, respectively. Our results provide novel insight to the role of immune system functioning in SA and BD and also suggest that integrating information from multiple levels of analysis holds promise to improve risk assessment for SA in adults with BD.

Epigenome-wide association study of DNA methylation in maternal blood leukocytes with BMI in pregnancy and gestational weight gain

ObjectivesWe aimed to discover CpG sites with differential DNA methylation in peripheral blood leukocytes associated with body mass index (BMI) in pregnancy and gestational weight gain (GWG) in women of European and South Asian ancestry. Furthermore, we aimed to investigate how the identified sites were associated with methylation quantitative trait loci, gene ontology, and cardiometabolic parameters.MethodsIn the Epigenetics in pregnancy (EPIPREG) sample we quantified maternal DNA methylation in peripheral blood leukocytes in gestational week 28 with Illumina’s MethylationEPIC BeadChip. In women with European (n = 303) and South Asian (n = 164) ancestry, we performed an epigenome-wide association study of BMI in gestational week 28 and GWG between gestational weeks 15 and 28 using a meta-analysis approach. Replication was performed in the Norwegian Mother, Father, and Child Cohort Study, the Study of Assisted Reproductive Technologies (MoBa-START) (n = 877, mainly European/Norwegian).ResultsWe identified one CpG site significantly associated with GWG (p 5.8 × 10−8) and five CpG sites associated with BMI at gestational week 28 (p from 4.0 × 10–8 to 2.1 × 10–10). Of these, we were able to replicate three in MoBa-START; cg02786370, cg19758958 and cg10472537. Two sites are located in genes previously associated with blood pressure and BMI. DNA methylation at the three replicated CpG sites were associated with levels of blood pressure, lipids and glucose in EPIPREG (p from 1.2 × 10−8 to 0.04).ConclusionsWe identified five CpG sites associated with BMI at gestational week 28, and one with GWG. Three of the sites were replicated in an independent cohort. Several genetic variants were associated with DNA methylation at cg02786379 and cg16733643 suggesting a genetic component influencing differential methylation. The identified CpG sites were associated with cardiometabolic traits.ClinicalTrials.gov registration noNot applicable

Loss of PPARα function promotes epigenetic dysregulation of lipid homeostasis driving ferroptosis and pyroptosis lipotoxicity in metabolic dysfunction associated Steatotic liver disease (MASLD).

Metabolic Dysfunction Associated Steatotic Liver Disease (MASLD) is a growing epidemic with an estimated prevalence of 20%-30% in Europe and the most common cause of chronic liver disease worldwide. The onset and progression of MASLD are orchestrated by an interplay of the metabolic environment with genetic and epigenetic factors. Emerging evidence suggests altered DNA methylation pattern as a major determinant of MASLD pathogenesis coinciding with progressive DNA hypermethylation and gene silencing of the liver-specific nuclear receptor PPARα, a key regulator of lipid metabolism. To investigate how PPARα loss of function contributes to epigenetic dysregulation in MASLD pathology, we studied DNA methylation changes in liver biopsies of WT and hepatocyte-specific PPARα KO mice, following a 6-week CDAHFD (choline-deficient, L-amino acid-defined, high-fat diet) or chow diet. Interestingly, genetic loss of PPARα function in hepatocyte-specific KO mice could be phenocopied by a 6-week CDAHFD diet in WT mice which promotes epigenetic silencing of PPARα function via DNA hypermethylation, similar to MASLD pathology. Remarkably, genetic and lipid diet-induced loss of PPARα function triggers compensatory activation of multiple lipid sensing transcription factors and epigenetic writer-eraser-reader proteins, which promotes the epigenetic transition from lipid metabolic stress towards ferroptosis and pyroptosis lipid hepatoxicity pathways associated with advanced MASLD. In conclusion, we show that PPARα function is essential to support lipid homeostasis and to suppress the epigenetic progression of ferroptosis-pyroptosis lipid damage associated pathways towards MASLD fibrosis.

DNA methylation analysis to differentiate reference, breed, and parent-of-origin effects in the bovine pangenome era.

Most DNA methylation studies have used a single reference genome with little attention paid to the bias introduced due to the reference chosen. Reference genome artifacts and genetic variation, including single nucleotide polymorphisms (SNPs) and structural variants (SVs), can lead to differences in methylation sites (CpGs) between individuals of the same species. We analyzed whole-genome bisulfite sequencing data from the fetal liver of Angus (Bos taurus taurus), Brahman (Bos taurus indicus), and reciprocally crossed samples. Using reference genomes for each breed from the Bovine Pangenome Consortium, we investigated the influence of reference genome choice on the breed and parent-of-origin effects in methylome analyses. Our findings revealed that ∼75% of CpG sites were shared between Angus and Brahman, ∼5% were breed specific, and ∼20% were unresolved. We demonstrated up to ∼2% quantification bias in global methylation when an incorrect reference genome was used. Furthermore, we found that SNPs impacted CpGs 13 times more than other autosomal sites (P < $5 \times {10}^{ - 324}$) and SVs contained 1.18 times (P < $5 \times {10}^{ - 324}$) more CpGs than non-SVs. We found a poor overlap between differentially methylated regions (DMRs) and differentially expressed genes (DEGs) and suggest that DMRs may be impacting enhancers that target these DEGs. DMRs overlapped with imprinted genes, of which 1, DGAT1, which is important for fat metabolism and weight gain, was found in the breed-specific and sire-of-origin comparisons. This work demonstrates the need to consider reference genome effects to explore genetic and epigenetic differences accurately and identify DMRs involved in controlling certain genes.

DNA methylation in amyotrophic lateral sclerosis: where do we stand and what is next?

Genes involved in immune response, inflammationand metabolism are among those most likely affected by changes in DNA methylation (DNAm)and expression levels in amyotrophic lateral sclerosis (ALS) tissues. Unfortunately, it is still largely unclear whether any of these changes precede the onset of disease symptoms or whether most of them are the result of the muscular and metabolic changes that follow symptoms onset. In this article the author discusses the strengths and limitations of the available studies of DNAm in ALS and provides some suggestions on what, in his opinion, could be done in the near future for a better understanding of the DNAm changes occurring in ALS, their link with environmental exposuresand their potential clinical utility.

Novel DNA methylation-based epigenetic signatures in colorectal cancer from peripheral blood leukocytes.

Colorectal cancer (CRC) is a multifactorial disease characterized by accumulation of multiple genetic and epigenetic alterations, transforming colonic epithelial cells into adenocarcinomas. Alteration of DNA methylation (DNAm) is a promising biomarker for predicting cancer risk and prognosis, but its role in CRC tumorigenesis is inconclusive. Notably, few DNAm studies have used pre-diagnostic peripheral blood (PB) DNA, causing difficulty in postulating the underlying biologic mechanism of CRC initiation. We conducted epigenome-wide association (EWA) scans in postmenopausal women from Women's Health Initiative (WHI) with their pre-diagnostic DNAm in PB leukocytes (PBLs) to prospectively evaluate CRC development. Our site-specific DNAm analyses across the genome adjusted for DNAm-age, leukocyte heterogeneities, as well as body mass index, diabetes, and insulin resistance. We validated 20 top EWA-CpGs in 2 independent CRC tissue datasets. Also, we detected differentially methylated regions (DMRs) associated with CRC, further mapped to transcriptomic profile, and finally conducted a Gene Set Enrichment Analysis. We detected multiple novel CpGs validated across WHI and tissue datasets. In particular, 2 CpGs (B4GALNT4cg10321339, SV2Bcg18144285) had the strongest effect on CRC risk. Results from our DMR scans contained MIR663cg06007966, which was also validated in EWA analyses. Also, we detected 1 methylome region in PEG10 of Chr7 shared across datasets. Our findings reflect both novel and well-established epigenomic and transcriptomic sites in CRC, warranting further functional validations. Our study contributes to better understanding of the complex interrelated mechanisms on the methylome underlying CRC tumorigenesis and suggests novel preventive DNAm-targets in PBLs for detecting at-risk individuals for CRC development.

A Clinical Study of DNA Methylation of JAM3 Gene in Predicting Cervical High-Grade Intraepithelial Neoplasia and Postoperative Recurrence

A Clinical Study of DNA Methylation of JAM3 Gene in Predicting Cervical High-Grade Intraepithelial Neoplasia and Postoperative Recurrence

Clinical role of NDRG2-based methylation status on survival pattern of glioblastoma.

Gliobalstoma is the most common primary brain tumor in adults with an extensive genetic and transcriptional heterogeneity, still identification of the role of DNA methylation, as one of epigenetic alterations, is emerged. Authors aimed to study the clinical role of N-myc downstream-regulated gene 2 (NDRG2) -based methylation among GBM patients versus benign neurological diseases (BND), investigate its prognostic role and its relation with survival outcomes. A total of 78 FFPE specimens were recruited as follows: GBM (n = 58) and BND (n = 20) then analyzed for NDRG2 methylation using Methyl II quantitative PCR system. The sensitivity and specificity of methylation was detected using receiver operating characteristic (ROC) curve and the relation with clinicopathological criteria for GBM and response to treatment were studied. Survival patterns; progression free survival (PFS) and overall survival (OS) were analyzed using Kaplan-Meier analyses. Mean methylation NDRG2 level was significantly increased in GBM patients as compared to BND and its sensitivity and specificity were 96.55% and 95%, respectively with area under curve (AUC) equals 0.973. Among the clinical characteristic factors, mean methylation level reported significant difference with ECOG and tumor site. Survival out comes revealed that NDRG2 methylation increased with worse PFS and OS at significant level (long rank test X2 = 13.3, p < .0001; and X2 = 7.1, p = .008, respectively). Current findings highlight the importance of studying DNA methylation of NDRG2 as a key factor to understand the role of epigenetic alterations in GBM.

DNA methylation as a window into female reproductive aging.

People with ovaries experience reproductive aging as their reproductive function and system declines. This has significant implications for both fertility and long-term health, with people experiencing an increased risk of cardiometabolic disorders after menopause. Reproductive aging can be assessed through markers of ovarian reserve, response to fertility treatmentor molecular biomarkers, including DNA methylation. Changes in DNA methylation with age associate with poorer reproductive outcomes, and epigenome-wide studies can provide insight into genes and pathways involved. DNA methylation-based epigenetic clocks can quantify biological age in reproductive tissues and systemically. This review provides an overview of hallmarks and theories of aging in the context of the reproductive system, and then focuses on studies of DNA methylation in reproductive tissues.