IGF2 DMR0 Methylation Research Articles

Methylation status of IGF2 DMR and LINE1 in leukocyte DNA provides distinct clinicopathological features of gastric cancer patients.

DNA methylation of leukocyte DNA has been proposed to be a biomarker for cancer that can be used to target patients for appropriate clinical implementation. We investigated IGF2 DMR and LINE1 methylation in the leukocyte DNA and their association with clinicopathological features and prognosis of gastric cancer (GC) patients. Methylation status of IGF2 DMR and LINE1 in the leukocyte DNA was quantified using bisulfite pyrosequencing in 207 GC patients. Methylation of both IGF2 DMR and the LINE1 was significantly higher in the undifferentiated histologic type compared to the differentiated histologic type (both P=0.0002). Hypermethylation of both the IGF2 DMR and the LINE1 was associated with more aggressive features of GC such as advanced stage (IGF2 DMR, P=0.0002; LINE1, P<0.0001), lymphatic invasion positive (IGF2 DMR, P=0.004; LINE1, P=0.002), venous invasion positive (IGF2 DMR, LINE1, both P=0.03), lymph node metastasis positive (IGF2 DMR, P=0.01; LINE1, P=0.001), peritoneal dissemination positive (IGF2 DMR, P=0.04; LINE1, P=0.002), liver metastasis positive (IGF2 DMR, P=0.008; LINE1, P=0.001), and other distant metastasis positive (IGF2 DMR, P=0.04). Our data suggest that high LINE1 and IGF2 DMR methylation status would be a phenomenon that is observed with the progression of GC, supporting their potential utility as a biomarker in GC patients.

Abstract 4930: Genetic and epigenetic characteristics of esophageal cancer tissues with microbiome fusobacterium nucleatum

Abstract Background: Research into the microbiome is a rapidly advancing field in human cancers. The gut microbiome has recently been shown to play an important role in health, as well as in diseases such as obesity, inflammatory bowel disease, diabetes, non-alcoholic fatty liver disease, and several types of cancers. Fusobacterium nucleatum is a component of the human microbiome that primarily inhabits the oral cavity. It causes periodontal disease and has also been implicated in the development of human cancers. We have recently reported that Fusobacterium nucleatum in esophageal cancer tissues was associated with shorter survival, suggesting a potential role as a prognostic biomarker. In addition, our KEGG enrichment analysis using microarray data showed that Fusobacterium nucleatum might also contribute to aggressive tumor behavior through activation of chemokines such as CCL20. Nonetheless, molecular features of Fusobacterium nucleatum-positive esophageal cancers have been still unknown. Methods: Using 325 esophageal cancers, we detected Fusobacterium nucleatum DNA in 74 tumors (23%). We assessed other genetic and epigenetic events including mutations in KRAS, BRAF, PIK3CA gene, p53 expression, phosphorylated-AKT expression, LINE-1 methylation level (global DNA methylation level), IGF2 DMR0 methylation, MGMT methylation, and MLH1 methylation. Results: The LINE-1 methylation levels of Fusobacterium nucleatum-positive tumors was significantly lower compared with that of Fusobacterium nucleatum-negative tumors (P&amp;lt;0.0001). In addition, Fusobacterium nucleatum was significantly associated with PIK3CA wild type (P=0.010). There was no relationship of Fusobacterium nucleatum with KRAS, BRAF mutation, p53 expression, p-AKT expression, IGF2 DMR0 methylation, MGMT methylation, or MLH1 methylation. Conclusion: Fusobacterium nucleatum was related with LINE-1 hypomethylation and PIK3CA wild type. Our findings may shed lights on understanding the mechanism by which Fusobacterium nucleatum affects aggressive tumor behavior. . Citation Format: Yoshifumi Baba, Kensuke Yamamura, Shigeki Nakagawa, Kosuke Mima, Takatsugu Ishimoto, Masaaki Iwatsuki, Yasuo Sakamoto, Naoya Yoshida, Hideo Baba. Genetic and epigenetic characteristics of esophageal cancer tissues with microbiome fusobacterium nucleatum [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4930. doi:10.1158/1538-7445.AM2017-4930

The effect of paternal methyl-group donor intake on offspring DNA methylation and birth weight.

Most nutritional studies on the development of children focus on mother-infant interactions. Maternal nutrition is critically involved in the growth and development of the fetus, but what about the father? The aim is to investigate the effects of paternal methyl-group donor intake (methionine, folate, betaine, choline) on paternal and offspring global DNA (hydroxy)methylation, offspring IGF2 DMR DNA methylation, and birth weight. Questionnaires, 7-day estimated dietary records, whole blood samples, and anthropometric measurements from 74 fathers were obtained. A total of 51 cord blood samples were collected and birth weight was obtained. DNA methylation status was measured using liquid chromatography-tandem mass spectrometry (global DNA (hydroxy)methylation) and pyrosequencing (IGF2 DMR methylation). Paternal betaine intake was positively associated with paternal global DNA hydroxymethylation (0.028% per 100 mg betaine increase, 95% CI: 0.003, 0.053, P=0.03) and cord blood global DNA methylation (0.679% per 100 mg betaine increase, 95% CI: 0.057, 1.302, P=0.03). Paternal methionine intake was positively associated with CpG1 (0.336% per 100 mg methionine increase, 95% CI: 0.103, 0.569, P=0.006), and mean CpG (0.201% per 100 mg methionine increase, 95% CI: 0.001, 0.402, P=0.049) methylation of the IGF2 DMR in cord blood. Further, a negative association between birth weight/birth weight-for-gestational age z-score and paternal betaine/methionine intake was found. In addition, a positive association between choline and birth weight/birth weight-for-gestational age z-score was also observed. Our data indicate a potential impact of paternal methyl-group donor intake on paternal global DNA hydroxymethylation, offspring global and IGF2 DMR DNA methylation, and prenatal growth.

Maternal intake of methyl-group donors affects DNA methylation of metabolic genes in infants

BackgroundMaternal nutrition during pregnancy and infant nutrition in the early postnatal period (lactation) are critically involved in the development and health of the newborn infant. The Maternal Nutrition and Offspring’s Epigenome (MANOE) study was set up to assess the effect of maternal methyl-group donor intake (choline, betaine, folate, methionine) on infant DNA methylation. Maternal intake of dietary methyl-group donors was assessed using a food-frequency questionnaire (FFQ). Before and during pregnancy, we evaluated maternal methyl-group donor intake through diet and supplementation (folic acid) in relation to gene-specific (IGF2 DMR, DNMT1, LEP, RXRA) buccal epithelial cell DNA methylation in 6 months old infants (n = 114) via pyrosequencing. In the early postnatal period, we determined the effect of maternal choline intake during lactation (in mothers who breast-fed for at least 3 months) on gene-specific buccal DNA methylation (n = 65).ResultsMaternal dietary and supplemental intake of methyl-group donors (folate, betaine, folic acid), only in the periconception period, was associated with buccal cell DNA methylation in genes related to growth (IGF2 DMR), metabolism (RXRA), and appetite control (LEP). A negative association was found between maternal folate and folic acid intake before pregnancy and infant LEP (slope = −1.233, 95% CI −2.342; −0.125, p = 0.0298) and IGF2 DMR methylation (slope = −0.706, 95% CI −1.242; −0.107, p = 0.0101), respectively. Positive associations were observed for maternal betaine (slope = 0.875, 95% CI 0.118; 1.633, p = 0.0241) and folate (slope = 0.685, 95% CI 0.245; 1.125, p = 0.0027) intake before pregnancy and RXRA methylation. Buccal DNMT1 methylation in the infant was negatively associated with maternal methyl-group donor intake in the first and second trimester of pregnancy and negatively in the third trimester. We found no clear association between maternal choline intake during lactation and buccal infant DNA methylation.ConclusionsThis study suggests that maternal dietary and supplemental intake of methyl-group donors, especially in the periconception period, can influence infant’s buccal DNA methylation in genes related to metabolism, growth, appetite regulation, and maintenance of DNA methylation reactions.

Prenatal parental tobacco smoking, gene specific DNA methylation, and newborns size: the Generation R study.

BackgroundDeleterious effects of prenatal tobacco smoking on fetal growth and newborn weight are well-established. One of the proposed mechanisms underlying this relationship is alterations in epigenetic programming. We selected 506 newborns from a population-based prospective birth cohort in the Netherlands. Prenatal parental tobacco smoking was assessed using self-reporting questionnaires. Information on birth outcomes was obtained from medical records. The deoxyribonucleic acid (DNA) methylation of the growth genes IGF2DMR and H19 was measured in newborn umbilical cord white blood cells. Associations were assessed between parental tobacco smoking and DNA methylation using linear mixed models and adjusted for potential confounders.ResultsThe DNA methylation levels of IGF2DMR and H19 in the non-smoking group were median (90 % range), 54.0 % (44.6–62.0), and 30.0 % (25.5–34.0), in the first trimester only smoking group 52.2 % (44.5–61.1) and 30.8 % (27.1–34.1), and in the continued smoking group 51.6 % (43.9–61.3) and 30.2 % (23.7–34.8), respectively. Continued prenatal maternal smoking was inversely associated with IGF2DMR methylation (β = −1.03, 95 % CI −1.76; −0.30) in a dose-dependent manner (P-trend = 0.030). This association seemed to be slightly more profound among newborn girls (β = −1.38, 95 % CI −2.63; −0.14) than boys (β = −0.72, 95 % CI −1.68; 0.24). H19 methylation was also inversely associated continued smoking <5 cigarettes/day (β = −0.96, 95 % CI −1.78; −0.14). Moreover, the association between maternal smoking and newborns small for gestational age seems to be partially explained by IGF2DMR methylation (β = −0.095, 95 % CI −0.249; −0.018). Among non-smoking mothers, paternal tobacco smoking was not associated with IGF2DMR or H19 methylation.ConclusionsMaternal smoking is inversely associated with IGF2DMR methylation in newborns, which can be one of the underlying mechanisms through which smoking affects fetal growth.Electronic supplementary materialThe online version of this article (doi:10.1186/s13148-015-0115-z) contains supplementary material, which is available to authorized users.

Intrauterine hyperglycemia environment alters IGF2 dmr methylation status of placenta in both first and second filial generations

Intrauterine hyperglycemia environment of gestational diabetes mellitus (GDM) could lead to abnormal gene expression of placenta in the offspring of GDM. Heritable transmission of differential gene expression may be related to epigenetic regulation. As imprinted genes, Igf2 expression in mice is regulated by allele-specific methylation at differentially methylated regions (DMRs). Therefore, the aim of our study is to examined the level of Igf2 expression in the first generation and the second generation offspring of GDM and investigate the potential epigenetic mechanism involved.

The impact of first trimester phthalate and phenol exposure on IGF2/H19 genomic imprinting and birth outcomes

Genomic imprinting leads to parent-of-origin specific gene expression and is determined by epigenetic modification of genes. The paternally expressed gene insulin-like growth-factor 2 (IGF2) is located about ~100kb from the maternally expressed non-coding gene H19 on human chromosome 11, and both genes play major roles in embryonic and placental growth. Given adverse gestational environments can influence DNA methylation patterns in extra-embryonic tissues, we hypothesized that prenatal exposure to endocrine disrupting chemicals (EDCs) alters H19 and IGF2 methylation in placenta. Our study was restricted to a total of 196 women co-enrolled in the Predictors of Preeclampsia Study and the Harvard Epigenetic Birth Cohort. First trimester urine concentrations of 8 phenols and 11 phthalate metabolites were measured and used to characterize EDC exposure profiles. We assessed methylation of differentially methylated regions (DMRs) by pyrosequencing of H19, IGF2DMR0, and IGF2DMR2 and correlated values with phenol and phthalate metabolites. We also assessed overall expression and allele-specific expression of H19 and IGF2. We found several significant associations between DNA methylation and additive biomarker measurements. A significant decrease in H19 methylation was associated with high levels of the sum (Σ) of phthalate metabolites and metabolites of low molecular weight (LMW) phthalates. Σphthalate and LMW phthalate concentrations were inversely associated with IGF2DMR0 methylation values. Variation in methylation was not associated with changes in allele-specific expression. However increased deviation of allele-specific expression of H19 was associated with Σdi(2-ethylhexyl) phthalate metabolites and high molecular weight phthalates. Neither methylation nor expression of these imprinted regions had a significant impact on birth length or birth weight. Overall, our study provides new insight into an epigenetic mechanism that occurs following EDC exposure.

Dietary supplementation with polyunsaturated fatty acid during pregnancy modulates DNA methylation at IGF2/H19 imprinted genes and growth of infants (1120.3)

Epigenetic regulations of imprinted genes are highly plausible explanation for the associations of dietary exposures in early life and the onset of diseases in adulthood. We tested whether prenatal dietary supplementation with docosahexaenoic acid (DHA) during pregnancy may modulate epigenetic states at birth in a randomized intervention trial among Mexican pregnant women supplemented daily with 400 mg of DHA or a placebo from 18 to 22 week of gestation to parturition. We applied quantitative profiling of DNA methylation states at IGF2 promoter 3 (IGF2 P3), IGF2 DMR and H19 DMR in cord blood mononuclear cells of the DHA‐supplemented group (n=131) and the control group (n=130).There were no significant differences between the DHA and the control groups for DNA methylation levels at imprinted genes; however in stratified analyses, we observed a positive association between DNA methylation levels and maternal BMI; IGF2 DMR methylation was higher in the DHA than the control groups in infants from overweight mother (p=0.03) and H19 DMR, methylation levels were significantly lower in the DHA than control groups in infants from normal weight mothers (p=0.01). Prenatal DHA supplementation modulated IGF2/H19 methylation in infants and methylation levels at IGF2/H19 imprinted regions were related with maternal BMI. Epigenetic mechanism may be modulated by DHA with potential impacts on growth and development of children.Grant Funding Source: NIH‐NICHHD (RO1HD058818), NIH (RO1HDO43099) and CONACYT Mexico (SALUD‐2008‐01‐87121)

IGF2 DMR0 Methylation, Loss of Imprinting, and Patient Prognosis in Esophageal Squamous Cell Carcinoma

Insulin like growth factor 2 gene (IGF2) is normally imprinted. Loss of imprinting (LOI) of IGF2 in humans is associated with an increased risk of cancer and is controlled by CpG-rich regions known as differentially methylated regions (DMRs). Specifically, the methylation level at IGF2 DMR0 is correlated with IGF2 LOI and is a suggested surrogate marker for IGF2 LOI. A relationship between IGF2 DMR0 hypomethylation and poor prognosis has been shown in colorectal cancer. However, to our knowledge, no study has examined the relationships among the IGF2 DMR0 methylation level, LOI, and clinical outcome in esophageal squamous cell carcinoma (ESCC). The IGF2 imprinting status was screened using ApaI polymorphism, and IGF2 protein expression was evaluated by immunohistochemistry with 30 ESCC tissue specimens. For survival analysis, IGF2 DMR0 methylation was measured using a bisulfite pyrosequencing assay with 216 ESCC tissue specimens. Twelve (40 %) of 30 cases were informative (i.e., heterozygous for ApaI), and 5 (42 %) of 12 informative cases displayed IGF2 LOI. IGF2 LOI cases exhibited lower DMR0 methylation levels (mean 23 %) than IGF2 non-LOI cases (37 %). The IGF2 DMR0 methylation level was significantly associated with IGF2 protein expression. Among 202 patients eligible for survival analysis, IGF2 DMR0 hypomethylation was significantly associated with higher cancer-specific mortality. The IGF2 DMR0 methylation level in ESCC was associated with IGF2 LOI and IGF2 protein expression. In addition, IGF2 DMR0 hypomethylation was associated with a shorter survival time, suggesting its potential role as a prognostic biomarker.

Association of IGF2 DMR0 hypomethylation in esophageal squamous cell carcinoma with poor prognosis.

11065 Background: The insulin-like growth factor 2 gene (IGF2) is normally imprinted. Loss of imprinting (LOI) of IGF2 in humans is associated with an increased risk of cancer and is controlled by CpG-rich regions known as differentially methylated regions (DMRs). Specifically, the methylation level at IGF2 DMR0 is correlated with IGF2 LOI and is a suggested surrogate marker for IGF2 LOI. A relationship between IGF2 DMR0 hypomethylation and poor prognosis has been shown in colorectal cancer. However, no study has examined the relationships among the IGF2 DMR0 methylation level, LOI, and clinical outcome in esophageal squamous cell carcinoma (ESCC). Methods: The IGF2 imprinting status was screened using ApaI polymorphism, and IGF2 protein expression was evaluated by immunohistochemistry with 30 ESCC tissue specimens. For survival analysis, IGF2 DMR0 methylation was measured using a bisulfite-pyrosequencing assay with 216 ESCC tissue specimens. The Cox proportional hazards model was used to calculate mortality hazard ratios (HR) adjusted for clinical, epidemiologic, and pathological variables.The term “prognostic marker” is used throughout this article according to the REMARK Guidelines. Results: Twelve (40%) of 30 cases were informative (i.e., heterozygous for ApaI), and 5 (42%) of 12 informative cases displayed IGF2 LOI. IGF2 LOI cases exhibited lower DMR0 methylation levels (mean, 23%) than IGF2 non-LOI cases (37%). The IGF2 DMR0 methylation level was significantly associated with IGF2 protein expression. Among 202 patients eligible for survival analysis, IGF2 DMR0 hypomethylation was significantly associated with higher cancer-specific mortality (log-rank P=0.013; univariate HR=2.03, 95% confidence interval: 1.14–3.58, P=0.017; multivariate HR=2.34, 95% CI: 1.29-4.22, P=0.0054). Conclusions: The IGF2 DMR0 methylation level in ESCC was associated with IGF2 LOI and IGF2 protein expression. In addition, IGF2 DMR0 hypomethylation was associated with a shorter survival time, suggesting its potential role as a prognostic biomarker.

Prenatal famine and genetic variation are independently and additively associated with DNA methylation at regulatory loci within IGF2/H19.

Both the early environment and genetic variation may affect DNA methylation, which is one of the major molecular marks of the epigenome. The combined effect of these factors on a well-defined locus has not been studied to date. We evaluated the association of periconceptional exposure to the Dutch Famine of 1944–45, as an example of an early environmental exposure, and single nucleotide polymorphisms covering the genetic variation (tagging SNPs) with DNA methylation at the imprinted IGF2/H19 region, a model for an epigenetically regulated genomic region. DNA methylation was measured at five differentially methylated regions (DMRs) that regulate the imprinted status of the IGF2/H19 region. Small but consistent differences in DNA methylation were observed comparing 60 individuals with periconceptional famine exposure with unexposed same-sex siblings at all IGF2 DMRs (PBH<0.05 after adjustment for multiple testing), but not at the H19 DMR. IGF2 DMR0 methylation was associated with IGF2 SNP rs2239681 (PBH = 0.027) and INS promoter methylation with INS SNPs, including rs689, which tags the INS VNTR, suggesting a mechanism for the reported effect of the VNTR on INS expression (PBH = 3.4×10−3). Prenatal famine and genetic variation showed similar associations with IGF2/H19 methylation and their contributions were additive. They were small in absolute terms (<3%), but on average 0.5 standard deviations relative to the variation in the population. Our analyses suggest that environmental and genetic factors could have independent and additive similarly sized effects on DNA methylation at the same regulatory site.

Commentary: Marking the epigenome—in search of the fingerprints of intrauterine nutritional deficiencies

Commentary: Marking the epigenome—in search of the fingerprints of intrauterine nutritional deficiencies

Association of genomic instability, and the methylation status of imprinted genes and mismatch-repair genes, with neural tube defects

We studied the genomic instability and methylation status of the mismatch-repair (MMR) genes hMLH1 and hMSH2, and the imprinted genes H19/IGF2, in fetuses with neural tube defects (NTDs) to explore the pathogenesis of the disease. Microsatellite instability (MSI) was observed in 23 of 50 NTD patients. Five NTD patients showed high-degree MSI (MSI-H) and 18 showed low-degree MSI (MSI-L). The frequencies of mutated microsatellite loci were 3/50 (6%) for BatT-25, 10/50 (20%) for Bat-26, 3/50 (6%) for Bat34C4, 6/50 (12%) for D2S123, 4/50 (8%) for D2S119, and 3/50 (6%) for D3S1611. The promoter regions of the hMLH1 and hMSH2 genes were unmethylated in NTD patients, as determined by methylation-specific PCR. The hMLH1 and hMSH2 promoter methylation patterns, the methylation levels of H19 DMR1, and IGF2 DMR0 were detected by bisulfite sequencing PCR, sub-cloning, and sequencing. The hMSH2 promoter sequence was unmethylated, and the hMLH1 promoter showed a specific methylation pattern at two CpG sites. The methylation levels of H19 DMR1 in the NTD and control groups are 73.3% ± 15.9 and 58.3% ± 11.2, respectively. The methylation level of the NTD group was higher than that of the control group (Student's t-test, P<0.05). There is no significant difference in IGF2 DMR0 methylation level between the two groups. All of the results presented here suggest that genomic instability, the MMR system, and hyper-methylation of the H19 DMR1 may be correlated with the occurrence of NTDs.

Sequential DNA methylation changes are associated with DNMT3B overexpression in colorectal neoplastic progression

Background and aimsAlthough aberrant methylation of key genes in the progression of colorectal neoplasia has been reported, no model-based analysis of the incremental changes through the intermediate adenoma stage has...

Periconceptional maternal folic acid use of 400 microg per day is related to increased methylation of the IGF2 gene in the very young child.

BackgroundCountries worldwide recommend women planning pregnancy to use daily 400 µg of synthetic folic acid in the periconceptional period to prevent birth defects in children. The underlying mechanisms of this preventive effect are not clear, however, epigenetic modulation of growth processes by folic acid is hypothesized. Here, we investigated whether periconceptional maternal folic acid use and markers of global DNA methylation potential (S-adenosylmethionine and S-adenosylhomocysteine blood levels) in mothers and children affect methylation of the insulin-like growth factor 2 gene differentially methylation region (IGF2 DMR) in the child. Moreover, we tested whether the methylation of the IGF2 DMR was independently associated with birth weight.Methodology/Principal Findings IGF2 DMR methylation in 120 children aged 17 months (SD 0.3) of whom 86 mothers had used and 34 had not used folic acid periconceptionally were studied. Methylation was measured of 5 CpG dinucleotides covering the DMR using a mass spectrometry-based method. Children of mother who used folic acid had a 4.5% higher methylation of the IGF2 DMR than children who were not exposed to folic acid (49.5% vs. 47.4%; p = 0.014). IGF2 DMR methylation of the children also was associated with the S-adenosylmethionine blood level of the mother but not of the child (+1.7% methylation per SD S-adenosylmethionine; p = 0.037). Finally, we observed an inverse independent association between IGF2 DMR methylation and birth weight (−1.7% methylation per SD birthweight; p = 0.034).ConclusionsPericonceptional folic acid use is associated with epigenetic changes in IGF2 in the child that may affect intrauterine programming of growth and development with consequences for health and disease throughout life. These results indicate plasticity of IGF2 methylation by periconceptional folic acid use.

Distinct Methylation Changes at the IGF2-H19 Locus in Congenital Growth Disorders and Cancer

BackgroundDifferentially methylated regions (DMRs) are associated with many imprinted genes. In mice methylation at a DMR upstream of the H19 gene known as the Imprint Control region (IC1) is acquired in the male germline and influences the methylation status of DMRs 100 kb away in the adjacent Insulin-like growth factor 2 (Igf2) gene through long-range interactions. In humans, germline-derived or post-zygotically acquired imprinting defects at IC1 are associated with aberrant activation or repression of IGF2, resulting in the congenital growth disorders Beckwith-Wiedemann (BWS) and Silver-Russell (SRS) syndromes, respectively. In Wilms tumour and colorectal cancer, biallelic expression of IGF2 has been observed in association with loss of methylation at a DMR in IGF2. This DMR, known as DMR0, has been shown to be methylated on the silent maternal IGF2 allele presumably with a role in repression. The effect of IGF2 DMR0 methylation changes in the aetiology of BWS or SRS is unknown.Methodology/Principal FindingsWe analysed the methylation status of the DMR0 in BWS, SRS and Wilms tumour patients by conventional bisulphite sequencing and pyrosequencing. We show here that, contrary to previous reports, the IGF2 DMR0 is actually methylated on the active paternal allele in peripheral blood and kidney. This is similar to the IC1 methylation status and is inconsistent with the proposed silencing function of the maternal IGF2 allele. Beckwith-Wiedemann and Silver-Russell patients with IC1 methylation defects have similar methylation defects at the IGF2 DMR0, consistent with IC1 regulating methylation at IGF2 in cis. In Wilms tumour, however, methylation profiles of IC1 and IGF2 DMR0 are indicative of methylation changes occurring on both parental alleles rather than in cis.Conclusions/SignificanceThese results support a model in which DMR0 and IC1 have opposite susceptibilities to global hyper and hypomethylation during tumorigenesis independent of the parent of origin imprint. In contrast, during embryogenesis DMR0 is methylated or demethylated according to the germline methylation imprint at the IC1, indicating different mechanisms of imprinting loss in neoplastic and non-neoplastic cells.