Abstract:BackgroundAberrant epigenetic modifications, including DNA methylation, are key regulators of gene activity in tumorigenesis. Breast cancer is a heterogeneous disease, and large-scale analyses indicate that tumor from normal and benign tissues, as well as molecular subtypes of breast cancer, can be distinguished based on their distinct genomic, transcriptomic, and epigenomic profiles. In this study, we used affinity-based methylation sequencing data in 30 breast cancer cell lines representing functionally dist… Show more
“…Similarly, one CGI consisting of 341 bp in the flanking region was detected from the1,250 bp canine LINE-1 5′UTR. Primers for bisulfite conversion PCR (BSC-PCR) were targeted on the shore region of CGIs because the association of CGI shore methylation status with breast cancers, especially a highly aggressive basal-like B type, has been reported 22 .Figure 3CpG island structure and methylation profile of LINE-1 5′UTR in breast cancer cell lines of human and dog. ( A ) LINE-1 structure ( B ) MethPrimer (http://www.urogene.org/cgi-bin/methprimer/methprimer.cgi) determined CpG Island structure in the 5′UTR of LINE-1 in both human and dog.…”
Breast cancer (BC) is one of the most common cancers in both women and female dogs. Methylation changes of LINE-1 have been reported in human cancers. The aim of this study was to determine the hypomethylation of canine LINE-1 in liquid biopsies for canine mammary tumors (CMT) and to assess its diagnostic performance in human plasma. BC associated LINE-1 methylation was measured by methylation sensitive (HpaII) and insensitive (MspI) restriction enzyme digestion followed by real-time PCR using the cfDNA isolated from 300 µl of plasma. The relative level of methylated canine LINE-1 was less than 0.4 in the benign and malignant CMTs (0.29 ± 0.061 and 0.39 ± 0.066, respectively) when it was 0.92 ± 0.067 in the healthy controls. The area under the ROC curve (AUC) was significantly high in both benign and malignant tumors (0.97 and 0.93). Furthermore, this approach was also successfully implemented in a set of 26 human BCs with 10 healthy controls (AUC = 0.78). Altogether, our data suggest that the comparative approach using a dog model might be helpful to rapidly develop a new diagnostic biomarker and that the methylation of LINE-1 in cfDNA may be a good target as a diagnostic marker of both human BC and CMT.
“…Similarly, one CGI consisting of 341 bp in the flanking region was detected from the1,250 bp canine LINE-1 5′UTR. Primers for bisulfite conversion PCR (BSC-PCR) were targeted on the shore region of CGIs because the association of CGI shore methylation status with breast cancers, especially a highly aggressive basal-like B type, has been reported 22 .Figure 3CpG island structure and methylation profile of LINE-1 5′UTR in breast cancer cell lines of human and dog. ( A ) LINE-1 structure ( B ) MethPrimer (http://www.urogene.org/cgi-bin/methprimer/methprimer.cgi) determined CpG Island structure in the 5′UTR of LINE-1 in both human and dog.…”
Breast cancer (BC) is one of the most common cancers in both women and female dogs. Methylation changes of LINE-1 have been reported in human cancers. The aim of this study was to determine the hypomethylation of canine LINE-1 in liquid biopsies for canine mammary tumors (CMT) and to assess its diagnostic performance in human plasma. BC associated LINE-1 methylation was measured by methylation sensitive (HpaII) and insensitive (MspI) restriction enzyme digestion followed by real-time PCR using the cfDNA isolated from 300 µl of plasma. The relative level of methylated canine LINE-1 was less than 0.4 in the benign and malignant CMTs (0.29 ± 0.061 and 0.39 ± 0.066, respectively) when it was 0.92 ± 0.067 in the healthy controls. The area under the ROC curve (AUC) was significantly high in both benign and malignant tumors (0.97 and 0.93). Furthermore, this approach was also successfully implemented in a set of 26 human BCs with 10 healthy controls (AUC = 0.78). Altogether, our data suggest that the comparative approach using a dog model might be helpful to rapidly develop a new diagnostic biomarker and that the methylation of LINE-1 in cfDNA may be a good target as a diagnostic marker of both human BC and CMT.
“…Only hypermethylation patterns in luminal subtypes might play roles in tumor progression but not that in basal-like subtype. In addition, studies of breast cancer cell lines have also identified distinct methylation patterns on CpG island shores among subtypes as well as hypomethylation in the basal-like B subtype 47 , 48 .…”
Malignant breast cancer remains a major health threat to women of all ages worldwide and epigenetic variations on DNA methylation have been widely reported in cancers of different types. We profiled DNA methylation with ERRBS (Enhanced Reduced Representation Bisulfite Sequencing) across four main stages of tumor progression in the MMTV-PyMT mouse model (hyperplasia, adenoma/mammary intraepithelial neoplasia, early carcinoma and late carcinoma), during which malignant transition occurs. We identified a large number of differentially methylated cytosines (DMCs) in tumors relative to age-matched normal mammary glands from FVB mice. Despite similarities, the methylation differences of the premalignant stages were distinct from the malignant ones. Many differentially methylated loci were preserved from the first to the last stage throughout tumor progression. Genes affected by methylation gains were enriched in Polycomb repressive complex 2 (PRC2) targets, which may present biomarkers for early diagnosis and targets for treatment.
“…The correlation between number of hypermethylated CpGs, number of genetic aberrations, and predicted mitotic age indicates an accumulation of alterations associated with number of cell divisions. Correlation between genetic and epigenetic alterations was shown previously in both chronic lymphatic leukemia [52] and in breast cancer cell lines [53], but less is known about correlations with mitotic age.…”
BackgroundClear cell renal cell carcinoma (ccRCC) is the most common subtype among renal cancer and is associated with poor prognosis if metastasized. Up to one third of patients with local disease at diagnosis will develop metastasis after nephrectomy, and there is a need for new molecular markers to identify patients with high risk of tumor progression. In the present study, we performed genome-wide promoter DNA methylation analysis at diagnosis to identify DNA methylation profiles associated with risk for progress.MethodDiagnostic tissue samples from 115 ccRCC patients were analysed by Illumina HumanMethylation450K arrays and methylation status of 155,931 promoter associated CpGs were related to genetic aberrations, gene expression and clinicopathological parameters.ResultsThe ccRCC samples separated into two clusters (cluster A/B) based on genome-wide promoter methylation status. The samples in these clusters differed in tumor diameter (p < 0.001), TNM stage (p < 0.001), morphological grade (p < 0.001), and patients outcome (5 year cancer specific survival (pCSS5yr) p < 0.001 and cumulative incidence of progress (pCIP5yr) p < 0.001. An integrated genomic and epigenomic analysis in the ccRCCs, revealed significant correlations between the total number of genetic aberrations and total number of hypermethylated CpGs (R = 0.435, p < 0.001), and predicted mitotic age (R = 0.407, p < 0.001). We identified a promoter methylation classifier (PMC) panel consisting of 172 differently methylated CpGs accompanying progress of disease. Classifying non-metastatic patients using the PMC panel showed that PMC high tumors had a worse prognosis compared with the PMC low tumors (pCIP5yr 38% vs. 8%, p = 0.001), which was confirmed in non-metastatic ccRCCs in the publically available TCGA-KIRC dataset (pCIP5yr 39% vs. 16%, p < 0.001).ConclusionDNA methylation analysis at diagnosis in ccRCC has the potential to improve outcome-prediction in non-metastatic patients at diagnosis.Electronic supplementary materialThe online version of this article (10.1186/s12885-019-5291-3) contains supplementary material, which is available to authorized users.
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