-
PloS One 2017Breastfeeding benefits both infants and mothers. Recent research shows long-term health and human capital benefits among individuals who were breastfed. Epigenetic... (Review)
Review
BACKGROUND
Breastfeeding benefits both infants and mothers. Recent research shows long-term health and human capital benefits among individuals who were breastfed. Epigenetic mechanisms have been suggested as potential mediators of the effects of early-life exposures on later health outcomes. We reviewed the literature on the potential effects of breastfeeding on DNA methylation.
METHODS
Studies reporting original results and evaluating DNA methylation differences according to breastfeeding/breast milk groups (e.g., ever vs. never comparisons, different categories of breastfeeding duration, etc) were eligible. Six databases were searched simultaneously using Ovid, and the resulting studies were evaluated independently by two reviewers.
RESULTS
Seven eligible studies were identified. Five were conducted in humans. Studies were heterogeneous regarding sample selection, age, target methylation regions, methylation measurement and breastfeeding categorisation. Collectively, the studies suggest that breastfeeding might be negatively associated with promoter methylation of LEP (which encodes an anorexigenic hormone), CDKN2A (involved in tumour suppression) and Slc2a4 genes (which encodes an insulin-related glucose transporter) and positively with promoter methylation of the Nyp (which encodes an orexigenic neuropeptide) gene, as well as influence global methylation patterns and modulate epigenetic effects of some genetic variants.
CONCLUSIONS
The findings from our systematic review are far from conclusive due to the small number of studies and their inherent limitations. Further studies are required to understand the actual potential role of epigenetics in the associations of breastfeeding with later health outcomes. Suggestions for future investigations, focusing on epigenome-wide association studies, are provided.
Topics: Breast Feeding; Cyclin-Dependent Kinase Inhibitor p16; Cyclin-Dependent Kinase Inhibitor p18; DNA Methylation; Epigenesis, Genetic; Female; Glucose Transporter Type 4; Humans; Infant; Longitudinal Studies; Male; Milk, Human
PubMed: 28257446
DOI: 10.1371/journal.pone.0173070 -
Clinical Epigenetics 2016Epigenetic mechanisms are important for the regulation of gene expression and differentiation in the fetus and the newborn child. Symptoms of maternal depression and... (Review)
Review
INTRODUCTION
Epigenetic mechanisms are important for the regulation of gene expression and differentiation in the fetus and the newborn child. Symptoms of maternal depression and antidepressant use affects up to 20 % of pregnant women, and may lead to epigenetic changes with life-long impact on child health. The aim of this review is to investigate whether there is an association between exposure to maternal antidepressants during pregnancy and epigenetic changes in the newborn.
MATERIAL AND METHODS
Systematic literature searches were performed in MEDLINE and EMBASE combining MeSH terms covering epigenetic changes, use of antidepressant medication, pregnancy and newborns. A keyword search was also performed. We included studies on pregnant women and their children where there was a history of maternal depressed mood or anxiety, a reported use of antidepressant medication, and measurements of epigenetic changes in umbilical cord blood. Studies using genome-wide or candidate-based epigenetic analyses were included. Citations and references from the included articles were investigated to locate further relevant articles. The completeness of reporting as well as the risk of bias and confounding was assessed.
RESULTS
Six studies were included. They all investigated methylation changes. Genome-wide methylation changes were examined in 184 children and methylation status in specific genes was examined in 96 children exposed to antidepressant medication. Three of the studies found an association between use of antidepressant medication during pregnancy and methylation status at various CpG sites measured in cord blood of the newborn. One of these studies found an association in African-Americans, but not Caucasians. The remaining three studies found associations between maternal mood and epigenetic changes in umbilical cord blood but no association between epigenetic changes and maternal use of antidepressant medication.
CONCLUSION
The included studies have not established a clear association between use of antidepressant medication during pregnancy and epigenetic changes in the cord blood. Future studies using newer, more wide-ranging epigenetic methods could discover possible new differentially methylated sites. Larger sample sizes and good validity of exposures are warranted in order to adjust for level of maternal depression, other maternal illness, maternal use of other types of medication, and maternal ethnicity. PROSPERO registration number: CRD42015026575.
Topics: Antidepressive Agents; DNA Methylation; Depression; Epigenesis, Genetic; Female; Fetal Blood; Humans; Maternal Exposure; Pregnancy; Pregnancy Complications
PubMed: 27610205
DOI: 10.1186/s13148-016-0262-x -
BMC Medical Genomics Aug 2016Whole-exome sequencing (WES) consists in the capture, sequencing and analysis of all exons in the human genome. Originally developed in the research context, this... (Review)
Review
BACKGROUND
Whole-exome sequencing (WES) consists in the capture, sequencing and analysis of all exons in the human genome. Originally developed in the research context, this technology is now increasingly used clinically to inform patient care. The implementation of WES into healthcare poses significant organizational, regulatory, and ethical hurdles, which are widely discussed in the literature.
METHODS
In order to inform future policy decisions on the integration of WES into standard clinical practice, we performed a systematic literature review to identify the most important challenges directly reported by technology users.
RESULTS
Out of 2094 articles, we selected and analyzed 147 which reported a total of 23 different challenges linked to the production, analysis, reporting and sharing of patients' WES data. Interpretation of variants of unknown significance, incidental findings, and the cost and reimbursement of WES-based tests were the most reported challenges across all articles.
CONCLUSIONS
WES is already used in the clinical setting, and may soon be considered the standard of care for specific medical conditions. Yet, technology users are calling for certain standards and guidelines to be published before this technology replaces more focused approaches such as gene panels sequencing. In addition, a number of infrastructural adjustments will have to be made for clinics to store, process and analyze the amounts of data produced by WES.
Topics: Exome; Genomics; High-Throughput Nucleotide Sequencing; Humans; Sequence Analysis, DNA
PubMed: 27514372
DOI: 10.1186/s12920-016-0213-6 -
Medicine Jun 2016Numerous original clinical studies have attempted to investigate the prognostic value of HER-2 overexpression in osteosarcoma, but the results of these studies are not... (Meta-Analysis)
Meta-Analysis Review
Numerous original clinical studies have attempted to investigate the prognostic value of HER-2 overexpression in osteosarcoma, but the results of these studies are not consistent. This meta-analysis and systematic review was performed to further assess the correlation between HER-2 expression and prognosis in patients with osteosarcoma. A detailed search of relevant publications was conducted using 7 electronic databases: PubMed, Embase, the Cochrane library, the Wanfang database, the China National Knowledge Internet (CNKI) database, the Chinese VIP database, and the Chinese Biological Medical (CBM) Database for publications through August 1, 2015, using the following keywords (HER-2 OR ErbB-2 OR C-erbB-2 OR neu) AND (osteosarcoma OR osteogenic tumor). The bibliographies of potentially relevant articles and identified articles were then searched by hand. Eligible studies were those that enrolled participants with osteosarcoma and provided survival outcome in HER-2 positive and negative groups. The hazard ratio (HR) and 95% confidence interval (CI) for each individual study was calculated and pooled to obtain integrated estimates, using random effects modeling. Sixteen studies involving 934 participants with osteosarcoma met our inclusion criteria. HER-2 overexpression was documented in 42.2% of patients with osteosarcoma. Compared with patients without HER-2 overexpression, those overexpressing HER-2 had decreased overall survival (HR = 2.03, 95% CI: 1.36-3.03, P < 0.001). Statistical associations between HER-2 overexpression and unfavorable overall survival (OS) were observed for both biopsy and surgical removal specimens (HR = 2.07, 95%CI: 1.16-3.72, P = 0.014; and HR = 2.02, 95%CI: 1.10-3.71, P = 0.024). Results for disease-free survival (DFS) were similar. Overexpression of HER-2 is significantly associated with poor outcome for patients with osteosarcoma and should be assessed at diagnosis and after surgery as a prognostic factor. However, larger-scale multicenter clinical studies are needed to further support these findings.
Topics: Biomarkers, Tumor; Biopsy; Bone Neoplasms; DNA, Neoplasm; Gene Expression Regulation, Neoplastic; Humans; Orthopedic Procedures; Osteosarcoma; Prognosis; Receptor, ErbB-2
PubMed: 27281068
DOI: 10.1097/MD.0000000000003661 -
Mutation Research. Reviews in Mutation... 2016Accumulating evidence suggests that epigenetic alterations play an important role in chemically-induced carcinogenesis. Although the epigenome and genome may be equally... (Review)
Review
Accumulating evidence suggests that epigenetic alterations play an important role in chemically-induced carcinogenesis. Although the epigenome and genome may be equally important in carcinogenicity, the genotoxicity of chemical agents and exposure-related transcriptomic responses have been more thoroughly studied and characterized. To better understand the evidence for epigenetic alterations of human carcinogens, and the potential association with genotoxic endpoints, we conducted a systematic review of published studies of genotoxic carcinogens that reported epigenetic endpoints. Specifically, we searched for publications reporting epigenetic effects for the 28 agents and occupations included in Monograph Volume 100F of the International Agency for the Research on Cancer (IARC) that were classified as "carcinogenic to humans" (Group 1) with strong evidence of genotoxic mechanisms of carcinogenesis. We identified a total of 158 studies that evaluated epigenetic alterations for 12 of these 28 carcinogenic agents and occupations (1,3-butadiene, 4-aminobiphenyl, aflatoxins, benzene, benzidine, benzo[a]pyrene, coke production, formaldehyde, occupational exposure as a painter, sulfur mustard, and vinyl chloride). Aberrant DNA methylation was most commonly studied, followed by altered expression of non-coding RNAs and histone changes (totaling 85, 59 and 25 studies, respectively). For 3 carcinogens (aflatoxins, benzene and benzo[a]pyrene), 10 or more studies reported epigenetic effects. However, epigenetic studies were sparse for the remaining 9 carcinogens; for 4 agents, only 1 or 2 published reports were identified. While further research is needed to better identify carcinogenesis-associated epigenetic perturbations for many potential carcinogens, published reports on specific epigenetic endpoints can be systematically identified and increasingly incorporated in cancer hazard assessments.
Topics: Animals; Carcinogenicity Tests; Carcinogens; Environmental Exposure; Epigenesis, Genetic; Gene Expression Regulation; Genetic Association Studies; Genetic Predisposition to Disease; Genetic Variation; Humans; Mutagenicity Tests; Mutagens; Occupational Exposure
PubMed: 27234561
DOI: 10.1016/j.mrrev.2016.03.004 -
BMC Medicine Mar 2016Whole genome sequencing (WGS) is becoming an important part of epidemiological investigations of infectious diseases due to greater resolution and cost reductions... (Review)
Review
BACKGROUND
Whole genome sequencing (WGS) is becoming an important part of epidemiological investigations of infectious diseases due to greater resolution and cost reductions compared to traditional typing approaches. Many public health and clinical teams will increasingly use WGS to investigate clusters of potential pathogen transmission, making it crucial to understand the benefits and assumptions of the analytical methods for investigating the data. We aimed to understand how different approaches affect inferences of transmission dynamics and outline limitations of the methods.
METHODS
We comprehensively searched electronic databases for studies that presented methods used to interpret WGS data for investigating tuberculosis (TB) transmission. Two authors independently selected studies for inclusion and extracted data. Due to considerable methodological heterogeneity between studies, we present summary data with accompanying narrative synthesis rather than pooled analyses.
RESULTS
Twenty-five studies met our inclusion criteria. Despite the range of interpretation tools, the usefulness of WGS data in understanding TB transmission often depends on the amount of genetic diversity in the setting. Where diversity is small, distinguishing re-infections from relapses may be impossible; interpretation may be aided by the use of epidemiological data, examining minor variants and deep sequencing. Conversely, when within-host diversity is large, due to genetic hitchhiking or co-infection of two dissimilar strains, it is critical to understand how it arose. Greater understanding of microevolution and mixed infection will enhance interpretation of WGS data.
CONCLUSIONS
As sequencing studies have sampled more intensely and integrated multiple sources of information, the understanding of TB transmission and diversity has grown, but there is still much to be learnt about the origins of diversity that will affect inferences from these data. Public health teams and researchers should combine epidemiological, clinical and WGS data to strengthen investigations of transmission.
Topics: Bacterial Typing Techniques; Genetic Variation; Genome, Bacterial; Genome-Wide Association Study; Humans; Mycobacterium tuberculosis; Recurrence; Sequence Analysis, DNA; Tuberculosis
PubMed: 27005433
DOI: 10.1186/s12916-016-0566-x -
Clinical and Translational... Mar 2016The controversy of CpG island methylator phenotype (CIMP) in colorectal cancers (CRCs) persists, despite many studies that have been conducted on its correlation with...
Tracking the Correlation Between CpG Island Methylator Phenotype and Other Molecular Features and Clinicopathological Features in Human Colorectal Cancers: A Systematic Review and Meta-Analysis.
OBJECTIVES
The controversy of CpG island methylator phenotype (CIMP) in colorectal cancers (CRCs) persists, despite many studies that have been conducted on its correlation with molecular and clinicopathological features. To drive a more precise estimate of the strength of this postulated relationship, a meta-analysis was performed.
METHODS
A comprehensive search for studies reporting molecular and clinicopathological features of CRCs stratified by CIMP was performed within the PubMed, EMBASE, and Cochrane Library. CIMP was defined by either one of the three panels of gene-specific CIMP markers (Weisenberger panel, classic panel, or a mixture panel of the previous two) or the genome-wide DNA methylation profile. The associations of CIMP with outcome parameters were estimated using odds ratio (OR) or weighted mean difference (WMD) or hazard ratios (HRs) with 95% confidence interval (CI) for each study using a fixed effects or random effects model.
RESULTS
A total of 29 studies involving 9,393 CRC patients were included for analysis. We observed more BRAF mutations (OR 34.87; 95% CI, 22.49-54.06) and microsatellite instability (MSI) (OR 12.85 95% CI, 8.84-18.68) in CIMP-positive vs. -negative CRCs, whereas KRAS mutations were less frequent (OR 0.47; 95% CI, 0.30-0.75). Subgroup analysis showed that only the genome-wide methylation profile-defined CIMP subset encompassed all BRAF-mutated CRCs. As expected, CIMP-positive CRCs displayed significant associations with female (OR 0.64; 95% CI, 0.56-0.72), older age at diagnosis (WMD 2.77; 95% CI, 1.15-4.38), proximal location (OR 6.91; 95% CI, 5.17-9.23), mucinous histology (OR 3.81; 95% CI, 2.93-4.95), and poor differentiation (OR 4.22; 95% CI, 2.52-7.08). Although CIMP did not show a correlation with tumor stage (OR 1.10; 95% CI, 0.82-1.46), it was associated with shorter overall survival (HR 1.73; 95% CI, 1.27-2.37).
CONCLUSIONS
The meta-analysis highlights that CIMP-positive CRCs take their own molecular feature, especially overlapping with BRAF mutations, and clinicopathological features and worse prognosis from CIMP-negative CRCs, suggesting CIMP could be used as an independent prognostic marker for CRCs.
PubMed: 26963001
DOI: 10.1038/ctg.2016.14 -
Evidence-based Complementary and... 2015Objective. To evaluate the efficacy and safety of Kushenin (KS) combined with nucleoside analogues (NAs) for chronic hepatitis B (CHB). Methods. Randomized controlled... (Review)
Review
Objective. To evaluate the efficacy and safety of Kushenin (KS) combined with nucleoside analogues (NAs) for chronic hepatitis B (CHB). Methods. Randomized controlled trials (RCTs) of KS combined with NAs for CHB were identified through 7 databases. Frequencies of loss of serum HBeAg, HBeAg seroconversion, undetectable serum HBV-DNA, ALT normalization, and adverse events at 48 weeks were abstracted by two reviewers. The Cochrane software was performed to assess the risk of bias in the included trials. Data were analyzed with Review Manager 5.3 software. Results. 18 RCTs involving 1684 subjects with CHB were included in the analysis. KS combined with NAs including lamivudine (LAM), entecavir (ETV), adefovir dipivoxil (ADV), and telbivudine (TLV) showed different degree of improvement in CHB indices. KS combined with NAs increased the frequency of loss of serum HBeAg, HBeAg seroconversion, undetectable HBV-DNA levels, and ALT normalization compared with single agents. It also decreased serum ALT and AST level after one-year treatment. However, KS combined with TLV did not show a significant difference in CHB indices. The side-effects of KS combined with NAs were light and of low frequency. Conclusion. KS combined with NAs improves the efficacy of NAs in CHB.
PubMed: 26347789
DOI: 10.1155/2015/529636 -
Gut Aug 2015Data on genetic susceptibility to sporadic gastric carcinoma have been published at a growing pace, but to date no comprehensive overview and quantitative summary has... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Data on genetic susceptibility to sporadic gastric carcinoma have been published at a growing pace, but to date no comprehensive overview and quantitative summary has been available.
METHODS
We conducted a systematic review and meta-analysis of the evidence on the association between DNA variation and risk of developing stomach cancer. To assess result credibility, summary evidence was graded according to the Venice criteria and false positive report probability (FPRP) was calculated to further validate result noteworthiness. Meta-analysis was also conducted for subgroups, which were defined by ethnicity (Asian vs Caucasian), tumour histology (intestinal vs diffuse), tumour site (cardia vs non-cardia) and Helicobacter pylori infection status (positive vs negative).
RESULTS
Literature search identified 824 eligible studies comprising 2 530 706 subjects (cases: 261 386 (10.3%)) and investigating 2841 polymorphisms involving 952 distinct genes. Overall, we performed 456 primary and subgroup meta-analyses on 156 variants involving 101 genes. We identified 11 variants significantly associated with disease risk and assessed to have a high level of summary evidence: MUC1 rs2070803 at 1q22 (diffuse carcinoma subgroup), MTX1 rs2075570 at 1q22 (diffuse), PSCA rs2294008 at 8q24.2 (non-cardia), PRKAA1 rs13361707 5p13 (non-cardia), PLCE1 rs2274223 10q23 (cardia), TGFBR2 rs3087465 3p22 (Asian), PKLR rs3762272 1q22 (diffuse), PSCA rs2976392 (intestinal), GSTP1 rs1695 11q13 (Asian), CASP8 rs3834129 2q33 (mixed) and TNF rs1799724 6p21.3 (mixed), with the first nine variants characterised by a low FPRP. We also identified polymorphisms with lower quality significant associations (n=110).
CONCLUSIONS
We have identified several high-quality biomarkers of gastric cancer susceptibility. These data will form the backbone of an annually updated online resource that will be integral to the study of gastric carcinoma genetics and may inform future screening programmes.
Topics: Gene Frequency; Genetic Predisposition to Disease; Genetic Variation; Genome-Wide Association Study; Humans; Neoplasm Proteins; Polymorphism, Genetic; Risk Factors; Stomach Neoplasms
PubMed: 25731870
DOI: 10.1136/gutjnl-2015-309168 -
HPB : the Official Journal of the... May 2015Endoscopic ultrasonography with fine needle aspiration (EUS-FNA) has become an integral tool in the diagnosis of pancreatic cystic lesions (PCLs) and the analysis of... (Review)
Review
BACKGROUND
Endoscopic ultrasonography with fine needle aspiration (EUS-FNA) has become an integral tool in the diagnosis of pancreatic cystic lesions (PCLs) and the analysis of molecular/DNA abnormalities might improve the accuracy of pre-operative diagnosis. A review was conducted of all studies using EUS-FNA aspirates of PCLs to assess the accuracy and added benefit that molecular analysis provides to cytological analysis.
METHODS
A systematic review of the literature was conducted using PRISMA guidelines and electronic databases: PubMed/SCOPUS/EMBASE/Cochrane/CINAHL. Surgical pathology was used as the definitive reference standard. The QUADAS-2 tool was used for quality assessment.
RESULTS
In total, 162 articles were identified; 12 articles met inclusion/exclusion criteria. Ten studies reported on cytology and 8 studies reported k-ras mutational analysis. 362 patients (of 1115 total) had surgical pathology available. The sensitivity and specificity of cytology was 0.42 and 0.99; the sensitivity and specificity of k-ras was 0.39 and 0.95; and the sensitivity and specificity of the combined test of cytology and k-ras was 0.71 and 0.88, respectively.
CONCLUSIONS
k-ras mutational analysis used as an individual screening test has a poor diagnostic accuracy, as does cytology when used alone. The benefit comes with utilization in a combined fashion. More studies are needed to evaluate the correct sequence and utility of these tests for cyst differentiation.
Topics: DNA; DNA Mutational Analysis; Endoscopic Ultrasound-Guided Fine Needle Aspiration; Genes, ras; Humans; Molecular Diagnostic Techniques; Pancreas; Pancreatic Cyst
PubMed: 25428782
DOI: 10.1111/hpb.12364