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International Journal of Molecular... Oct 2022The characteristic epigenetic profile of periodontitis found in peripheral leukocytes denotes its impact on systemic immunity. In fact, this profile not only stands for... (Review)
Review
The characteristic epigenetic profile of periodontitis found in peripheral leukocytes denotes its impact on systemic immunity. In fact, this profile not only stands for periodontitis as a low-grade inflammatory disease with systemic effects but also as an important source of potentially valuable clinical biomarkers of its systemic effects and susceptibility to other inflammatory conditions. Thus, we aimed to identify relevant genes tested as epigenetic systemic biomarkers in patients with periodontitis, based on the DNA methylation patterns and RNA expression profiles in peripheral immune cells. A detailed protocol was designed following the Preferred Reporting Items for Systematic Review and Meta-analysis -PRISMA guideline. Only cross-sectional and case-control studies that reported potential systemic biomarkers of periodontitis in peripheral immune cell types were included. DNA methylation was analyzed in leukocytes, and gene expression was in polymorphonuclear and mononuclear cells. Hypermethylation was found in TLR regulators genes: , , , , , , and in early stages of periodontitis, while advanced stages presented hypomethylation of these genes. , , , and genes were differentially expressed in lymphocytes and monocytes of subjects with poorly controlled diabetes mellitus, dyslipidemia, and periodontitis in comparison with controls. The gene was differentially overexpressed in periodontitis and dyslipidemia. Peripheral blood neutrophils in periodontitis showed differential expression in 163 genes. Periodontitis showed an increase in ceruloplasmin gene expression in polymorphonuclears in comparison with controls. Several genes highlight the role of the epigenetics of peripheral inflammatory cells in periodontitis that could be explored in blood as a source of biomarkers for routine testing.
Topics: Biomarkers; Ceruloplasmin; Cross-Sectional Studies; DNA Methylation; Dyslipidemias; Gene Expression; Humans; Myeloid Differentiation Factor 88; Periodontitis; RNA
PubMed: 36233348
DOI: 10.3390/ijms231912042 -
Journal of Oral Pathology & Medicine :... Feb 2024Aberrant epigenetic modifications significantly develop and progress human malignancies including head and neck squamous cell carcinoma (HNSCC). Taking into account... (Review)
Review
BACKGROUND
Aberrant epigenetic modifications significantly develop and progress human malignancies including head and neck squamous cell carcinoma (HNSCC). Taking into account issues of late diagnosis and poor prognosis associated with HNSCC, this systematic review is designed to provide an up-to-date insight of epigenetic changes in the management of HNSCC.
METHODS
All studies that assessed the diagnostic and prognostic utilities of epigenetic changes (DNA methylation and histone modifications) among patients diagnosed with HNSCC or oral potentially malignant disorders (OPMDs) were considered for inclusion till June 2023. Pre-defined Medical Subject Headings terms were used to search Web of Science, Pubmed, Scopus and Embase Ovid databases.
RESULTS
Twenty-five studies were deemed eligible for inclusion with a total number of 3790 samples (2123 HNSCCs, 334 OPMDs and 1333 as controls). DNA methylation was investigated in 18 studies while the role of histone modifications was assessed in seven studies. The most investigated biomarkers among the studies were H3, DAPK and TIMP3. The diagnostic accuracy of the epigenetic biomarkers in detecting HNSCC was assessed in eight studies where the following biomarkers showed the highest area under the curve values: TIPM3, DCC, DAPK, SEPT9, SHOX9, HOXA9 and TRH. None of the studies assessed the predictability of the epigenetic biomarkers in HNSCC and OPMDs.
CONCLUSION
Although initial promising results were seen using the epigenetic biomarkers in the early detection of HNSCC, the limited number of patients and the absence of well-designed longitudinal studies limit the clinical applicability of the outcomes.
Topics: Humans; Squamous Cell Carcinoma of Head and Neck; Epigenesis, Genetic; Head and Neck Neoplasms; DNA Methylation; Prognosis; Biomarkers, Tumor
PubMed: 38316046
DOI: 10.1111/jop.13513 -
International Journal of Molecular... Mar 2023Cervical intraepithelial neoplasia grade 2 (CIN2) is an intermediate stage between CIN 1, which is a low-grade lesion, and CIN3, which is the immediate precursor of... (Review)
Review
Cervical intraepithelial neoplasia grade 2 (CIN2) is an intermediate stage between CIN 1, which is a low-grade lesion, and CIN3, which is the immediate precursor of cervical cancer (CC). Traditionally, CIN2 was regarded as a high-grade lesion and was treated with conization or ablative methods. In recent years, there has been a shift in the management of younger patients, who are now more often being managed conservatively due to frequent spontaneous CIN2 regression and possible adverse effects of treatment on future pregnancies. Because the risk of progression to CC still exists with conservative management, a personalized approach is needed to identify patients with a higher probability of progression. In this regard, research has focused on the role of host and human papillomavirus (HPV) gene methylation. This systematic review summarizes the current knowledge regarding conservative CIN2 management focusing on the main methylation markers and its implementation in conservative CIN2 management, and it describes major ongoing longitudinal studies on the subject. The review showed that DNA methylation is an accurate predictor of disease progression and a valid triage tool for HPV-positive women, with CIN2 performing better than triage cytology. Because virtually all CCs are methylation-positive, methylation-negative women at baseline have an extremely low risk of CC.
Topics: Pregnancy; Humans; Female; Human Papillomavirus Viruses; Papillomavirus Infections; Uterine Cervical Dysplasia; Uterine Cervical Neoplasms; DNA Methylation; DNA; Papillomaviridae
PubMed: 37047452
DOI: 10.3390/ijms24076479 -
Frontiers in Immunology 2022Glioblastoma (GBM) is the most common malignant brain tumor in adults, and immunotherapies and genetic therapies for GBM have evolved dramatically over the past decade,... (Review)
Review
Glioblastoma (GBM) is the most common malignant brain tumor in adults, and immunotherapies and genetic therapies for GBM have evolved dramatically over the past decade, but GBM therapy is still facing a dilemma due to the high recurrence rate. The inflammatory microenvironment is a general signature of tumors that accelerates epigenetic changes in GBM and helps tumors avoid immunological surveillance. GBM tumor cells and glioma-associated microglia/macrophages are the primary contributors to the inflammatory condition, meanwhile the modification of epigenetic events including DNA methylation, non-coding RNAs, and histone methylation and deacetylases involved in this pathological process of GBM, finally result in exacerbating the proliferation, invasion, and migration of GBM. On the other hand, histone deacetylase inhibitors, DNA methyltransferases inhibitors, and RNA interference could reverse the inflammatory landscapes and inhibit GBM growth and invasion. Here, we systematically review the inflammatory-associated epigenetic changes and regulations in the microenvironment of GBM, aiming to provide a comprehensive epigenetic profile underlying the recognition of inflammation in GBM.
Topics: Brain Neoplasms; Epigenesis, Genetic; Glioblastoma; Humans; Inflammation; Tumor Microenvironment
PubMed: 35572545
DOI: 10.3389/fimmu.2022.869307 -
Artificial Intelligence in Medicine Sep 2023DNA methylation biomarkers have great potential in improving prognostic classification systems for patients with cancer. Machine learning (ML)-based analytic techniques... (Review)
Review
BACKGROUND
DNA methylation biomarkers have great potential in improving prognostic classification systems for patients with cancer. Machine learning (ML)-based analytic techniques might help overcome the challenges of analyzing high-dimensional data in relatively small sample sizes. This systematic review summarizes the current use of ML-based methods in epigenome-wide studies for the identification of DNA methylation signatures associated with cancer prognosis.
METHODS
We searched three electronic databases including PubMed, EMBASE, and Web of Science for articles published until 2 January 2023. ML-based methods and workflows used to identify DNA methylation signatures associated with cancer prognosis were extracted and summarized. Two authors independently assessed the methodological quality of included studies by a seven-item checklist adapted from 'A Tool to Assess Risk of Bias and Applicability of Prediction Model Studies (PROBAST)' and from the 'Reporting Recommendations for Tumor Marker Prognostic Studies (REMARK). Different ML methods and workflows used in included studies were summarized and visualized by a sunburst chart, a bubble chart, and Sankey diagrams, respectively.
RESULTS
Eighty-three studies were included in this review. Three major types of ML-based workflows were identified. 1) unsupervised clustering, 2) supervised feature selection, and 3) deep learning-based feature transformation. For the three workflows, the most frequently used ML techniques were consensus clustering, least absolute shrinkage and selection operator (LASSO), and autoencoder, respectively. The systematic review revealed that the performance of these approaches has not been adequately evaluated yet and that methodological and reporting flaws were common in the identified studies using ML techniques.
CONCLUSIONS
There is great heterogeneity in ML-based methodological strategies used by epigenome-wide studies to identify DNA methylation markers associated with cancer prognosis. In theory, most existing workflows could not handle the high multi-collinearity and potentially non-linearity interactions in epigenome-wide DNA methylation data. Benchmarking studies are needed to compare the relative performance of various approaches for specific cancer types. Adherence to relevant methodological and reporting guidelines are urgently needed.
Topics: Humans; DNA Methylation; Epigenome; Prognosis; Neoplasms; Machine Learning
PubMed: 37673571
DOI: 10.1016/j.artmed.2023.102589 -
Mechanisms of Ageing and Development Oct 2020Alzheimer's disease (AD) is the most widespread neurodegenerative disorder and has caused a major global health concern with the aging of the population. Recent studies...
Alzheimer's disease (AD) is the most widespread neurodegenerative disorder and has caused a major global health concern with the aging of the population. Recent studies have suggested a role for epigenetic mechanisms in AD. DNA methylation is a vital component of the epigenetic machinery which is the best-studied example covered by epigenetics. Studies of DNA methylation have been proceeded in different brain samples, peripheral blood and both in AD. But little is known about whether the easily accessible tissue, peripheral blood, can be used to address questions about epigenetic variations in brain which would normally be inaccessible. Here, we provide a systemic review of the DNA methylation as well as hydromethylation profiles in in human brain and peripheral blood samples of AD. We found that APP gene was the only one that consistently hypermethylated in both brain and peripheral blood, which suggested it could be the most promising diagnostic blood marker of AD in the future, and more energy need to be devoted to studies of DNA methylation after cell classification.
Topics: Aging; Alzheimer Disease; Animals; Brain; DNA Methylation; Epigenesis, Genetic; Humans
PubMed: 32721406
DOI: 10.1016/j.mad.2020.111319 -
Lupus Mar 2023Traditionally, the diagnosis and monitoring of disease activity in systemic lupus erythematosus (SLE) are contingent upon clinical manifestations and serological...
BACKGROUND
Traditionally, the diagnosis and monitoring of disease activity in systemic lupus erythematosus (SLE) are contingent upon clinical manifestations and serological markers. However, researchers are struggling to find biomarkers with higher sensitivity and specificity. DNA methylation has been the most studied epigenetic feature in SLE. So, in this study, we performed a systematic review of studies about DNA methylation alterations in SLE patients compared to healthy controls.
METHODS
By searching PubMed, Scopus, and Google Scholar up to July 2022, all case-control studies in which DNA methylation of specific genes was assessed by a non-high-throughput technique and passed the quality of bias assessment were included.
RESULTS
In total, 44 eligible studies underwent a data extraction process. In all, 3471 SLE patients and 1028 healthy individuals were included. Among the studies that reported the patients' gender ( = 2853), 89.41% were female and 10.59% were male. Forty studies have been conducted on adult patients. The number of works on fractionated and unfractionated blood cells was almost equal. In this regard, 22 studies were conducted on whole blood or peripheral blood mononuclear cells and two studies on unfractionated white blood cells. Sorted blood cells were biological sources in 20 studies. The most investigated gene was . Sensitivity, specificity, and diagnostic power of methylation levels were only reported for in five studies. The most employed methylation profiling method was bisulfite sequencing polymerase chain reaction. The correlation between methylation patterns and clinical parameters was explored in 22 studies, which of them 16 publications displayed a remarkable association between DNA methylation status and clinical indices.
CONCLUSIONS
The methylation status of some genes especially , , and has been suggested as promising SLE biomarkers. However, given the conflicting findings between studies because of potential confounders such as different sample types, methylation profiling methods, and ethnicity as well as shared DNA methylation patterns of SLE and other autoimmune diseases, DNA methylation biomarkers are currently not reliable diagnostic biomarkers and do not represent surrogate markers of SLE disease activity. Future investigations on a larger scale with the discarding of limitations of previous studies would probably lead to a consensus.
Topics: Adult; Humans; Male; Female; DNA Methylation; Leukocytes, Mononuclear; Lupus Erythematosus, Systemic; Genetic Markers; Case-Control Studies
PubMed: 36573333
DOI: 10.1177/09612033221148099 -
Journal of Neurology, Neurosurgery, and... Dec 2023Biological ageing is one of the principal risk factors for neurodegenerative diseases. It is becoming increasingly clear that acceleration of DNA methylation age, as...
BACKGROUND
Biological ageing is one of the principal risk factors for neurodegenerative diseases. It is becoming increasingly clear that acceleration of DNA methylation age, as measured by the epigenetic clock, is closely associated with many age-related diseases.
METHODS
We searched the PubMed and Web of Science databases to identify eligible studies reporting epigenetic clocks in several neurodegenerative diseases, including Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS) and Huntington's disease (HD).
RESULTS
Twenty-three studies (12 for AD, 4 for PD, 5 for ALS, and 2 for HD) were included. We systematically summarised the clinical utility of 11 epigenetic clocks (based on blood and brain tissues) in assessing the risk factors, age of onset, diagnosis, progression, prognosis and pathology of AD, PD, ALS and HD. We also critically described our current understandings to these evidences, and further discussed key challenges, potential mechanisms and future perspectives of epigenetic ageing in neurodegenerative diseases.
CONCLUSIONS
Epigenetic clocks hold great potential in neurodegenerative diseases. Further research is encouraged to evaluate the clinical utility and promote the application.
PROSPERO REGISTRATION NUMBER
CRD42022365233.
Topics: Humans; Amyotrophic Lateral Sclerosis; Neurodegenerative Diseases; Alzheimer Disease; Parkinson Disease; Epigenesis, Genetic
PubMed: 36963821
DOI: 10.1136/jnnp-2022-330931 -
Expert Review of Molecular Diagnostics Sep 2022The aim is to evaluate the association of methylation with esophageal cancer (EC) risk. (Meta-Analysis)
Meta-Analysis
OBJECTIVE
The aim is to evaluate the association of methylation with esophageal cancer (EC) risk.
METHODS
The PubMed, Embase, Web of Science, and Cochrane Library databases were systematically searched to identify relevant articles. Pooled odds ratios (ORs) with 95% confidence interval (CI) were estimated using the fixed- or random-effects models. The pooled sensitivity and specificity were calculated to assess the diagnostic value of methylation for EC. The results of the meta-analysis were validated using The Cancer Genome Atlas and Gene Expression Omnibus databases.
RESULTS
Thirteen studies consisting of 1,633 samples were included. A high methylation was significantly associated with an increased risk of EC (OR = 10.40, 95% CI = 6.29-17.18). Furthermore, methylation status was related to tumor status, lymph node status, and metastasis. For the diagnosis of EC, the pooled sensitivity and specificity of methylation were 0.57 (95% CI = 0.39-0.74) and 0.89 (95% CI = 0.81-0.94), respectively. Bioinformatics analysis showed that methylation occurred more frequently in EC tissues than in normal controls, in good agreement with the results of the meta-analysis.
CONCLUSION
A significant association was found between methylation and EC risk. We therefore suggest that methylation can serve as a promising diagnostic marker for EC.
Topics: Humans; Computational Biology; DNA Methylation; Esophageal Neoplasms; Odds Ratio; Antigens, CD; Cadherins
PubMed: 36254608
DOI: 10.1080/14737159.2022.2132853 -
Iranian Journal of Public Health Dec 2021The tumor suppressor genes play a critical role in cellular and molecular mechanisms such as cell cycle processes, cell differentiation and apoptosis. Aberrant DNA... (Review)
Review
BACKGROUND
The tumor suppressor genes play a critical role in cellular and molecular mechanisms such as cell cycle processes, cell differentiation and apoptosis. Aberrant DNA methylation of tumor suppressor genes and subsequent gene expression changes have shown to be involved in the initiation and progression of various malignancies including thyroid malignancies. In this review, we investigated what is known about the impact of promoter hypermethylation on the key tumor suppressor genes known to be involved in cell growth and/or apoptosis of thyroid cancer.
METHODS
The most important databases were searched for research articles until June 2020 to identify reported tumor suppressor genes that are modulated by methylation modulation changes in thyroid carcinoma. Following the inclusion and exclusion criteria, 26 studies were reviewed using the full text to meet the inclusion and exclusion criteria.
RESULTS
The tumor suppressor genes reviewed here are suggestive biomarkers and potential targetable drugs. Inactivation of , , , and through aberrant epigenetic methylation could activate BRAF/MEK/ERK kinase pathways with potential clinical implications in thyroid cancer patients. and could suppress cell cycle and induce apoptosis in malignant cells. and could prevent angiogenesis and invasion through PIP3 pathway and arrest VEFG activity.
CONCLUSION
The methylation status of key genes in various types of thyroid malignancies could be used in early diagnosis as well as differentiation of malignant and benign thyroid. This is valuable in drug repurposing and discovering alternative treatments or preventions in thyroid cancer.
PubMed: 36317025
DOI: 10.18502/ijph.v50i12.7928