Multiplex Methylation-specific PCR Research Articles

Abnormal Promoter Methylation of Nucleotide-Binding Oligomerization Domain Containing 2 (NOD2) Gene in the Pathogenesis of Crohn’s Disease

Background: Changes in the expression of nucleotide-binding oligomerization domain containing 2 (NOD2) play an important role in the pathogenesis of a variety of autoimmune diseases including inflammatory bowel diseases (IBDs). Epigenetic modifications, including DNA methylation, are considered an important mechanism in the suppression of gene activity. In this study, we investigated the relationship between DNA methylation patterns of the promoter region of the NOD2 gene and the pathogenesis of Crohn’s disease (CD). Methods: Colonic mucosa samples were obtained from 15 Iranian patients with IBD and 15 age- and sexmatched healthy controls with no history of autoimmune disease. After the bisulfite conversion of genomic DNA, the DNA methylation status of three CpG sites in the promoter region of the NOD2 gene was determined by the real-time quantitative multiplex methylation-specific PCR (QM-MSP) assay. Results: Using this approach, we identified that IBD patients showed a decreased level of methylation of the NOD2 promoter in the colonic mucosa than did the healthy controls. (Unmethylated DNA in Crohn's disease vs. healthy controls; 0.128±0.093 vs. 0.025±0.016, P<0.000). Conclusion: According to our findings, promoter hypomethylation of the NOD2 gene in the colonic mucosa might contribute to the development and severity of CD. Furthermore, aberrant DNA methylation levels are expected to serve as a clinically useful risk marker.

94P A one-tube multiplex methylation-specific droplet digital PCR assay for identification of ctDNA biomarkers in anal squamous cell carcinoma

94P A one-tube multiplex methylation-specific droplet digital PCR assay for identification of ctDNA biomarkers in anal squamous cell carcinoma

Promotor Hypomethylation of TFF1 Gene in Ulcerative Colitis is Positively Correlated with Aging

Background: Epigenetic modifications exhibit promising evidence in the etiology and prognosis of important diseases such as inflammatory bowel diseases (IBD). In addition to complex factors involved in IBD, a trend toward better prognosis has been reported in older ages of disease onset, specifically in ulcerative colitis (UC). The gastrointestinal mucous layer is one of the important components that is disturbed in the disease course. The integrity of this layer is maintained with an anti-inflammatory factor called trefoil factors (TFF). We investigated the methylation status of the TFF1 gene in UC patients alongside with correlation of its alteration level with age of disease onset. Method: We analyzed the promoter methylation status of the TFF1 gene, using the real-time quantitative multiplex methylation specific PCR (QM-MSP). DNA was extracted from colorectal biopsies of 15 ulcerative colitis and 14 healthy controls. Correlation analysis was performed between unmethylated DNA level and age through the Pearson correlation coefficient (PPC) test and simple linear regression models. Results: Our data provided a significant positive correlation between age and TFF1 hypomethylation in ulcerative colitis patients. However, no significant difference was observed in overall TFF1 methylation status between ulcerative colitis patients and control subjects. Conclusion: This finding suggests the association between epigenetic upregulation of the TFF1 gene with disease mildness in older patients.

MIR124-3 and NKX6-1 hypermethylation profiles accurately predict metachronous gastric lesions in a Caucasian population

BackgroundEarly gastric cancer is treated endoscopically, but patients require surveillance due to the risk of metachronous gastric lesions (MGLs). Epigenetic alterations, particularly aberrant DNA methylation in genes, such as MIR124-3, MIR34b/c, NKX6-1, EMX1, MOS and CDO1, have been identified as promising biomarkers for MGL in Asian populations. We aimed to determine whether these changes could predict MGL risk in intermediate-risk Caucasian patients.MethodsThis case–cohort study included 36 patients who developed MGL matched to 48 patients without evidence of MGL in the same time frame (controls). Multiplex quantitative methylation-specific PCR was performed using DNA extracted from the normal mucosa adjacent to the primary lesion. The overall risk of progression to MGL was assessed using Kaplan–Meier and Cox proportional hazards model analyses.ResultsMIR124-3, MIR34b/c and NKX6-1 were successfully analyzed in 77 samples. MIR124-3 hypermethylation was detected in individuals who developed MGL (relative quantification 78.8 vs 50.5 in controls, p = 0.014), particularly in females and Helicobacter pylori-negative patients (p = 0.021 and p = 0.0079, respectively). This finding was further associated with a significantly greater risk for MGL development (aHR = 2.31, 95% CI 1.03–5.17, p = 0.042). Similarly, NKX6-1 was found to be hypermethylated in patients with synchronous lesions (relative quantification 7.9 vs 0.0 in controls, p = 0.0026). A molecular-based methylation model incorporating both genes was significantly associated with a threefold increased risk for MGL development (aHR = 3.10, 95% CI 1.07–8.95, p = 0.037).ConclusionsThis preliminary study revealed an association between MIR124-3 and NKX6-1 hypermethylation and the development of MGL in a Western population. These findings may represent a burden reduction and a greener approach to patient care.

Methylation Status of SOCS1 and SOCS3 Genes in Patients with Acute Lymphoid Leukemia

Background: Acute Lymphoid Leukemia (ALL) is the leading childhood cancer with a high mortality and morbidity. Studies have suggested an association of epigenetic transformations with prognosis, recurrence and immunophenotypes of ALL. SOCS1 and SOCS3 are tumor suppressors inhibiting JAK/STAT signaling pathway and the resultant aberrant cell proliferation.
 Method: We aimed to assess the association between methylation status and ALL, using bone marrow and peripheral blood samples. 18 patients with ALL and 13 children with no malignancies were included. Using Bisulfite conversion, quantitative multiplex methylation-specific PCR and 2^(-∆∆Ct) formula, the methylated DNA in the promoters of SOCS1 and SOCS3 were measured.
 Results: ALL patients had higher mean methylation in SOCS1 promoter and lower mean methylation in SOCS3 promoter, compared to the control group. However, neither of these mean differences were statistically significant.
 Conclusion: This finding can set the foundation for further large-sample studies with the use of healthy children as a control group to strengthen the hypothetical association of the methylation status of SOCS1 and SOCS3 with ALL.

Analytical validation and diagnostic performance of the ASCL1/ZNF582 methylation test for detection of high-grade anal intraepithelial neoplasia and anal cancer

DNA methylation testing on biopsies can detect high-grade anal intraepithelial neoplasia (HGAIN) in need of treatment and anal cancer. This study aimed to analytically validate and determine the diagnostic performance of a newly developed multiplex quantitative methylation-specific PCR, PreCursor-M AnoGYN (RUO), combining ASCL1, ZNF582 and a reference (ACTB) in one assay. Analytical validation was performed on two qPCR devices using predefined quality criteria. Diagnostic performance was determined on a cross-sectional series of 111 anal biopsies covering all stages of anal disease. Differences in methylation levels were assessed using the Kruskal-Wallis test. Area under the curve was determined using logistic regression analysis. Detection rates were calculated at predefined specificities for the cross-sectional and an additional longitudinal series of 23 HGAIN biopsies preceding anal cancer (i.e., progressive HGAIN).For both devices analytical quality criteria were met. ASCL1 and ZNF582 methylation levels increased with increasing severity of disease (p < 6*10−8). Diagnostic performance for AIN3+ was 0.81. All cancers and virtually all progressive HGAIN were detected at 70% and 80% specificity.In conclusion, the ASCL1/ZNF582 methylation test (PreCursor-M AnoGYN (RUO)) was demonstrated to be highly robust and reproducible. Moreover, it had excellent diagnostic accuracy to detect AIN3+ and can potentially be used to guide HGAIN management.

B-382 Accurate and Early Detection of Colorectal Cancer Using a Multilocus DNA Methylation Markers-based Testing in Peripheral Blood Mononuclear Cells

Abstract Background An effective blood-based method for the diagnosis of colorectal cancer (CRC) has not yet been developed. Molecular alterations of immune cells occur early in tumorigenesis, providing the theoretical underpinning for early cancer diagnosis. Therefore, we aimed to develop an effective multi-molecular simultaneous detection method based on peripheral blood mononuclear cells (PBMCs) to improve the diagnosis of early-stage CRC. Methods Candidate DNA methylation markers were first identified from PBMCs using the Infinium MethylationEPIC array in the discovery phase (Shandong cohort I, n = 100) and further validated via pyrosequencing and targeted bisulfite sequencing in validation phase (Shandong cohort II, n = 202). Then, a single-tube multiplex methylation-specific quantitative PCR assay (multi-msqPCR) for simultaneous detection of five markers was established in a pilot study. After that, a CRC prediction model (CPM) based on DNA methylation and multi-msqPCR method was construct and its diagnostic performance were evaluated using the area under the receiver operating characteristic curve (AUROC) in our multicenter cohort (n = 595). Results Five discriminative DNA methylation markers identified by Illumina 850K microarray were successfully validated to diagnose early-stage CRC. Multi-msqPCR showed a better discriminative performance and 10-time lower detection limit than single-molecule detection in early-stage CRC. The cross-validated AUROC for CPM for early-stage CRC was 0.91 (sensitivity = 81.18%; specificity = 89.39%), significantly higher than CEA (AUROC = 0.62). CPM assay also yielded a high degree of discrimination for advanced adenoma (AA) cases (AUROC = 0.85; sensitivity = 63.04%; specificity = 89.39%). Besides, detecting CPM in multiple cancer types implied a CRC-specific diagnostic value. Our follow-up data also demonstrated that CPM could detect early-stage CRC up to 2 years before current traditional diagnostic methods. Conclusions CPM, in combination with epigenetic biomarkers and the multi-msqPCR method, was promising, cost-effective, and easily implementable for routine clinical diagnosis of early-stage CRC.

B-381 A Multiplex Blood-based Assay Targeting DNA methylation in Peripheral Blood Mononuclear Cells Enables Early Detection of Breast Cancer

Abstract Background The immune system can monitor the development of tumors, and the DNA methylation is involved in the body immune response to tumors. Therefore, the DNA from peripheral blood mononuclear cell (PBMC) that carries cancer-specific epigenetic aberrations may serve as a non-invasive marker for early detection of breast cancer (BC). Methods Genome-wide DNA methylation profiling on PBMC DNA from BC patients and healthy controls (Cohort I, n = 80) was performed in the discovery phase by Infinium 850K BeadChips. The candidate CpG sites were selected and validated in a multistep validation phase (Cohort II, n = 200) via pyrosequencing and targeted bisulfite sequencing. After that, the multiplex quantitative methylation-specific PCR assay (mBC-MSP) was established to detect BC, and the performance of this diagnostic method was analyzed in a multicenter cohort (Cohort III, n = 501). Results A total of 289 differentially methylated CpG positions (DMPs) between BC patients and healthy controls were identified. Among them, eight significant DMPs markers were selected and further validated using pyrosequencing and targeted bisulfite sequencing, and four hyper-methylated DMPs (cg18637238, cg16652347, cg13828440, cg11754974) passed the final validation. Then, we developed a mBC-MSP assay based on the four methylated markers. This assay exhibited excellent performance in distinguishing BC patients, with an AUC of 0.925, sensitivity of 83.1%, and specificity of 90.4%. More importantly, compared with CA153, CA125 and CEA, the mBC-MSP assay had higher sensitivity for early-stage BC (stage 0, 88.2% vs 0%, 0%, 5.9%) and minimal tumor with diameter ≤1.5 cm (91.7% vs 0%, 2.1%, 0%). Conclusions The mBC-MSP assay based on the four identified DNA methylation markers from PBMC can serve as a noninvasive, accurate, rapid, and high-throughput method for early diagnosis of BC, and it is more sensitive than traditional tumor markers for detecting early-stage BC and minimal tumor.

Abnormal Promoter Methylation of Nucleotide-Binding Oligomerization Domain Containing 2 (NOD2) Gene in the Pathogenesis of Crohn’s Disease

Changes in the expression of nucleotide-binding oligomerization domain containing 2 (NOD2) play an important role in the pathogenesis of several autoimmune diseases, such as inflammatory bowel diseases (IBD), including Crohn’s disease (CD) and ulcerative colitis (UC). It seems that epigenetic modifications, including DNA methylation, have an important role in the suppression of gene activity. In this study, the relationship between DNA methylation patterns of the promoter region of the NOD2 gene and the pathogenesis of CD was assessed. Colonic mucosal samples were obtained from 15 Iranian patients with CD and 15 matched healthy controls with no history of autoimmune diseases. After bisulfite conversion of genomic DNA, the DNA methylation status of three CpG sites in the promoter region of the NOD2 gene was determined by the real-time quantitative multiplex methylation-specific PCR assay. Using this approach, we identified a decreased level of methylation of the NOD2 promoter in the colonic mucosa of patients with CD (0.128±0.093 vs. 0.025±0.016, unmethylated DNA in CD vs. healthy controls, respectively, P&lt;0.000). According to our findings, promoter hypomethylation of the NOD2 gene in the colonic mucosa might contribute to the development and severity of CD.

A multiplex blood-based assay targeting DNA methylation in PBMCs enables early detection of breast cancer

The immune system can monitor tumor development, and DNA methylation is involved in the body’s immune response to tumors. In this work, we investigate whether DNA methylation alterations in peripheral blood mononuclear cells (PBMCs) could be used as markers for early detection of breast cancer (BC) from the perspective of tumor immune alterations. We identify four BC-specific methylation markers by combining Infinium 850 K BeadChips, pyrosequencing and targeted bisulfite sequencing. Based on the four methylation markers in PBMCs of BC, we develop an efficient and convenient multiplex methylation-specific quantitative PCR assay for the detection of BC and validate its diagnostic performance in a multicenter cohort. This assay was able to distinguish early-stage BC patients from normal controls, with an AUC of 0.940, sensitivity of 93.2%, and specificity of 90.4%. More importantly, this assay outperformed existing clinical diagnostic methods, especially in the detection of early-stage and minimal tumors.

Methylation testing for the detection of recurrent cervical intraepithelial neoplasia.

Women treated for CIN2/3 remain at increased risk of recurrent CIN and cervical cancer, and therefore posttreatment surveillance is recommended. This post hoc analysis evaluates the potential of methylation markers ASCL1/LHX8 and FAM19A4/miR124-2 for posttreatment detection of recurrent CIN2/3. Cervical scrapes taken at 6 and 12 months posttreatment of 364 women treated for CIN2/3 were tested for methylation of ASCL1/LHX8 and FAM19A4/miR124-2 using quantitative multiplex methylation-specific PCR. Performance of the methylation tests were calculated and compared with the performance of HPV and/or cytology. Methylation levels of recurrent CIN were compared between women with a persistent HPV infection, and women with an incident HPV infection or without HPV infection. Recurrent CIN2/3 was detected in 42 women (11.5%), including 28 women with CIN2 and 14 with CIN3. ASCL1/LHX8 tested positive in 13/14 (92.9%) of recurrent CIN3 and 13/27 (48.1%) of recurrent CIN2. FAM19A4/miR124-2 tested positive in 14/14 (100%) of recurrent CIN3 and 10/27 (37.0%) of recurrent CIN2. Combined HPV and/or methylation testing showed similar positivity rates as HPV and/or cytology. The CIN2/3 risk at 12 months posttreatment was 30.8% after a positive ASCL1/LHX8 result at 6 months posttreatment. Methylation levels of CIN2/3 in women with a persistent HPV infection were significantly higher compared with women with an incident or no HPV infection. In conclusion, posttreatment monitoring by methylation analysis of ASCL1/LHX8 and FAM19A4/miR124-2 showed a good performance for the detection of recurrent CIN. DNA methylation testing can help to identify women with recurrent CIN that require re-treatment.

Quantitative Evaluation of NOD2 Promoter Methylation Profiling in Colon Biopsy Samples from Ulcerative Colitis Patients and Non-Colitis Controls

Background: Ulcerative colitis (UC) is an idiopathic chronic inflammatory disease of the colon with evidence addressing the role of epigenetic changes. The intention of this study was to detect the association of DNA methylation levels of NOD2 gene with UC and to evaluate whether any of these changes might be a useful biomarker for detecting patients with UC.&#x0D; Methods: The methylation status of the promoter CpG islands (CGIs) of NOD2 gene was examined in the colonic mucosae of 15 cancer-free patients with UC and 15 age- and sex-matched healthy controls by the real-time quantitative multiplex-methylation specific PCR (QM-MSP) assay. Methylation-specific melting curve analysis (MS-MCA) were used to analyze the data.&#x0D; Results: The median unmethylated DNA index was significantly higher in cases compared to controls, and hypormethylation of NOD2 gene was significantly correlated with UC (Unmethylated DNA in UC vs. HC; 0.102±0.055 vs. 0.025±0.016, P = 0.000).&#x0D; Conclusion: The NOD2 gene that was differentially methylated in UC patients, providing new insights into the pathogenesis of UC, with a view to making steps toward the development of accurate biomarkers for diagnostic tools in UC.

Evaluation of DNA methylation biomarkers ASCL1 and LHX8 on HPV-positive self-collected samples from primary HPV-based screening

BackgroundHost-cell DNA methylation analysis can be used to triage women with high-risk human papillomavirus (HPV)-positive self-collected cervicovaginal samples, but current data are restricted to under-/never-screened women and referral populations. This study evaluated triage performance in women who were offered primary HPV self-sampling for cervical cancer screening.MethodsSelf-collected samples from 593 HPV-positive women who participated in a primary HPV self-sampling trial (IMPROVE study; NTR5078), were tested for the DNA methylation markers ASCL1 and LHX8 using quantitative multiplex methylation-specific PCR (qMSP). The diagnostic performance for CIN3 and cervical cancer (CIN3 + ) was evaluated and compared with that of paired HPV-positive clinician-collected cervical samples.ResultsSignificantly higher methylation levels were found in HPV-positive self-collected samples of women with CIN3 + than control women with no evidence of disease (P values <0.0001). The marker panel ASCL1/LHX8 yielded a sensitivity for CIN3 + detection of 73.3% (63/86; 95% CI 63.9–82.6%), with a corresponding specificity of 61.1% (310/507; 95% CI 56.9–65.4%). The relative sensitivity for detecting CIN3+ was 0.95 (95% CI 0.82–1.10) for self-collection versus clinician-collection, and the relative specificity was 0.82 (95% CI 0.75–0.90).ConclusionsThe ASCL1/LHX8 methylation marker panel constitutes a feasible direct triage method for the detection of CIN3 + in HPV-positive women participating in routine screening by self-sampling.

Clinical validation of methylation biomarkers for optimal detection of high-grade vulvar intraepithelial neoplasia.

The precursor lesions of vulvar squamous cell carcinoma (VSCC) include human papillomavirus (HPV)-associated and HPV-independent squamous neoplasia with a varying cancer risk. Our study aimed to validate the accuracy of previously identified DNA methylation markers for detection of such high-grade vulvar intraepithelial neoplasia (VIN). A large clinical series of 751 vulvar lesions, originally diagnosed as high-grade VIN, were reassessed and categorized into HPV-associated or HPV-independent vulvar disease categories. Together with 113 healthy vulvar controls, all samples were tested for 12 methylation markers with quantitative multiplex methylation-specific PCR (qMSP). Performance of individual markers and selection of an optimal marker panel for detection of high-grade VIN was determined by logistic regression analysis. SST was the best-performing individual marker (AUC 0.90), detecting 80% of high-grade VIN cases, with excellent detection of HPV-independent VIN (95%), known to have the highest cancer risk. Merely 2% of controls tested methylation positive for SST. Selection of a marker panel, including ZNF582, SST and miR124-2, resulted in a comparably high accuracy for detection of high-grade VIN (AUC 0.89). In conclusion, we clinically validated the accuracy of 12 DNA methylation markers for detection of high-grade VIN. SST, as a sole marker or in a panel, provides an optimal diagnostic tool to distinguish high-grade VIN in need of treatment, particularly HPV-independent VIN, from low-grade or reactive vulvar lesions. These findings warrant further prognostic validation of methylation biomarkers for cancer risk stratification of patients with VIN.

Multiplex Digital Methylation-Specific PCR for Noninvasive Screening of Lung Cancer.

There remains tremendous interest in developing liquid biopsy assays for detection of cancer-specific alterations, such as mutations and DNA methylation, in cell-free DNA (cfDNA) obtained through noninvasive blood draws. However, liquid biopsy analysis is often challenging due to exceedingly low fractions of circulating tumor DNA (ctDNA), necessitating the use of extended tumor biomarker panels. While multiplexed PCR strategies provide advantages such as higher throughput, their implementation is often hindered by challenges such as primer-dimers and PCR competition. Alternatively, digital PCR (dPCR) approaches generally offer superior performance, but with constrained multiplexing capability. This paper describes development and validation of the first multiplex digital methylation-specific PCR (mdMSP) platform for simultaneous analysis of four methylation biomarkers for liquid-biopsy-based detection of non-small cell lung cancer (NSCLC). mdMSP employs a microfluidic device containing four independent, but identical modules, housing a total of 40 160 nanowells. Analytical validation of the mdMSP platform demonstrates multiplex detection at analytical specificities as low as 0.0005%. The clinical utility of mdMSP is also demonstrated in a cohort of 72 clinical samples of low-volume liquid biopsy specimens from patients with computed tomography(CT)-scan indeterminant pulmonary nodules, exhibiting superior clinical performance when compared to traditional MSP assays for noninvasive detection of early-stage NSCLC.

DNA Methylation of JAK2 Gene in Intestinal Biopsy and Peripheral Blood Samples of Patients with Ulcerative Colitis

Background: Comprised of two main subtypes (Ulcerative Colitis (UC) and Crohn), inflammatory bowel disease is caused by an interaction between genetic and environmental factors. As of the important role of innate immunity and JAK/STAT signaling pathway, the current study was designed to investigate the methylation status JAK2 gene in blood and tissue samples of patients with UC.&#x0D; Methods: Genomic DNA was extracted from blood and intestinal biopsy samples of 28 UC patients and 28 controls. After bisulfite DNA conversion, real-time quantitative multiplex methylation specific PCR (QM-MSP) method was applied in order to assess JAK2 promotor methylation status.&#x0D; Results: The JAK2 promotor in the intestinal biopsy samples was significantly hypermethylated in UC as the mean of unmethylated DNA was 1.255±1.865 in the patients group, while it was 1.292±4.726 in control group.&#x0D; Conclusion: Hypermathylation of JAK2 gene may play a part in pathophysiology of UC which could result in gene silencing.

Association between Promotor hypomethylation of TFF1 and Crohn's Disease.

Background and aim:Epigenetic modifications exhibit promising evidence in etiology and prognosis of important diseases such as inflammatory bowel diseases (IBD). In addition to complex factors involved in IBD, a trend toward better prognosis have been reported in older ages of disease onset. Gastrointestinal mucous layer is one of the important components which is disturbed in the disease course. Integrity of this layer is maintained with an anti-inflammatory factor called trefoil factors (TFF). We investigated the methylation status of TFF1 gene in IBD patients alongside with correlation of its alteration level with age of disease onset.Methods:We analyzed the promoter methylation status of TFF1 gene, using the real-time quantitative multiplex methylation specific PCR (QM-MSP). DNA was extracted from colorectal biopsies of 15 Crohn disease cases and 15 healthy controls. Correlation analysis was performed between unmethylated DNA level and age through Pearson correlation coefficient (PPC) test and simple linear regression models.Results:Our data didn’t provide significant positive correlation of age and TFF1 hypomethylation in Crohn patients (r = .518, p = .058).Conclusions:In conclusion, our case-control study didn’t show significant alteration in TFF1 methylation status in CD patients. (www.actabiomedica.it)

Association of Aberrant Promoter Methylation Changes in the Suppressor of Cytokine Signaling 3 (SOCS3) Gene with Susceptibility to Crohn's Disease.

Background:Growing evidence supports that changes in the methylation state of Inflammatory Bowel Disease (IBD)-associated genes could significantly alter levels of gene expression, potentially contributing to disease onset and progression. We supposed that alterations in DNA methylation status at promoter region within the suppressor of cytokine signaling 3 (SOCS3) gene in intestinal tissues may be involved in the susceptibility to Crohn's Disease (CD).Methods:DNA methylation status in the promoter region of the human SOCS3 gene of intestinal tissues from 15 patients with CD and 15 age- and sex-matched healthy controls were profiled using the real-time Quantitative Multiplex Methylation Specific PCR (QM-MSP) assay.Results:Based on methylation assay data profiling, we found that patients with CD showed a higher degree of methylation of the SOCS3 gene promoter region than did the healthy controls (unmethylated DNA in CD vs. healthy controls; 0.00048±0.0011 vs. 0.07±0.142, p<0.000).Conclusion:The data presented here demonstrate that aberrant methylation of the CpG islands within promoter regions of SOCS3 gene in colonic mucosa of CD was associated with mucosal inflammatory status, providing insights into the involvement of methylation could contribute to the initiation of the inflammatory process and development of CD.

High performance methylated DNA markers for detection of colon adenocarcinoma

BackgroundColon cancer (CC) is treatable if detected in its early stages. Improved CC detection assays that are highly sensitive, specific, and available at point of care are needed. In this study, we systematically selected and tested methylated markers that demonstrate high sensitivity and specificity for detection of CC in tissue and circulating cell-free DNA.MethodsHierarchical analysis of 22 candidate CpG loci was conducted using The Cancer Genome Atlas (TCGA) COAD 450K HumanMethylation database. Methylation of 13 loci was analyzed using quantitative multiplex methylation-specific PCR (QM-MSP) in a training set of fresh frozen colon tissues (N = 53). Hypermethylated markers were identified that were highest in cancer and lowest in normal colon tissue using the 75th percentile in Mann–Whitney analyses and the receiver operating characteristic (ROC) statistic. The cumulative methylation status of the marker panel was assayed in an independent test set of fresh frozen colon tissues (N = 52) using conditions defined and locked in the training set. A minimal marker panel of 6 genes was defined based on ROC area under the curve (AUC). Plasma samples (N = 20 colorectal cancers, stage IV and N = 20 normal) were tested by cMethDNA assay to evaluate marker performance in liquid biopsy.ResultsIn the test set of samples, compared to normal tissue, a 6-gene panel showed 100% sensitivity and 90% specificity for detection of CC, and an AUC of 1.00 (95% CI 1.00, 1.00). In stage IV colorectal cancer plasma versus normal, an 8-gene panel showed 95% sensitivity, 100% specificity, and an AUC of 0.996 (95% CI 0.986, 1.00) while a 5-gene subset showed 100% sensitivity, 100% specificity, and an AUC of 1.00 (95% CI 1.00, 1.00), highly concordant with our observations in tissue.ConclusionsWe identified high performance methylated DNA marker panels for detection of CC. This knowledge has set the stage for development and implementation of novel, automated, self-contained CC detection assays in tissue and blood which can expeditiously and accurately detect colon cancer in both developed and underdeveloped regions of the world, enabling optimal use of limited resources in low- and middle-income countries.

Glutathione S transferase T1 gene polymorphism and its promoter methylation are associated with breast cancer susceptibility in Egyptian women.

Breast cancer (BC) is one of the leading causes of cancer mortality in women. Glutathione S-transferase (GSTT1) is involved in activation of detoxification reactions and catalysis of chemicals conjugation with glutathione. GSTT1 genotype is a limiting factor for some environmental diseases. Epigenetic changes have an essential role in BC through inappropriate interaction between genomic and environmental risk factors. This study was directed to explore the association of BC risk with GSTT1 genetic variations and its methylation status in Egyptian women. This study included 100 healthy women as the control group and 100 patients were clinically and histologically diagnosed with breast cancer. All blood samples were used for genomic DNA extraction. GSTT1 genotyping was accomplished by multiplex PCR and methylation-specific PCR was used to analyze the GSTT1 promoter methylation status. Breast cancer patients showed significant incidence of null GSTT1 in relation to controls (p = 0.004). GSTT1 gene promoter methylation status showed significant difference between hypermethylated and unmethylated patients when compared with healthy subjects (p = 0.005). GSTT1 promoter methylation status was not significantly associated with null genotype. There was no significant association between GSTT1-null genotypes and BC stage in cases with or without family history, but for promotor methylation, there was significant association with stage III and IV breast cancer disease. GSTT1 null genetic variant and promoter hypermethylation in the GSTT region of the gene may be considered as critical risk factors for BC in Egyptian women.