Search

Background: CpG methylation of tumor suppressor genes occurs in the early stage of carcinogenesis. Detecting risk factors for aberrant CpG methylation is clinically important for predicting cancer development. DNA methyltransferase (DNMT) 3a is considered to play critical roles in the DNA methylation process during pathogenesis. In this study, we evaluated the association between DNMT3A polymorphisms (rs6733868 and rs13428812) and CpG methylation status in non-cancerous gastric mucosa., Methods: We determined the DNMT3A genotype and CpG methylation status of 4 genes (p14 ARF , p16 INK4a , DAPK, and CDH1) in 510 subjects without gastric cancer. Helicobacter pylori (HP) infection status was determined by the rapid urease test, urea breath test, speculum examination, or serum antibody test. We determined the DNMT3A genotype using polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP). CpG methylation status was determined by methylation-specific polymerase chain reaction (MSP). When the methylated band was stronger than 10 ng/μL according to the DNA marker, we judged CpG island hypermethylation (CIHM) to be present. Associations between genotypes and susceptibilities were assessed by logistic regression analysis., Results: The minor allele frequencies of both polymorphisms (rs6733868 and rs13428812) were lower in the CpG methylated groups of each of the 4 genes (p14 ARF , p16 INK4a , DAPK, and CDH1). Using a dominant genetic model, rs6733868 was significantly associated with the hypermethylation of each gene, whereas rs13428812 was associated with the methylation of 3 genes (all except p14 ARF ). When low-CIHM was defined as 1 or 2 CpG islands methylated and high-CIHM was defined as 3 or more CpG islands methylated, carrying the minor allele of rs6733868 was associated with both decreased low- and high-CIHM, and that of rs13428812 also was associated with a decrease. Comparing low-CIHM with high-CIHM, carrying the minor alleles of rs6733868 or rs13428812 was related to decreased susceptibility to high-CIHM. In HP-infected subjects, carrying the minor alleles of rs6733868 or rs13428812 had a significantly greater association with decreased susceptibility to high-CIHM., Conclusions: Our study indicates that polymorphisms of DNMT3A are associated with the accumulation of gene methylation in gastric mucosa. Carrying the minor alleles of rs6733868 or rs13428812 inhibits aberrant gene methylations, which are typically enhanced by HP infection.

Background: CDKN2A hypermethylation is among the major events associated with carcinogenesis and is also observed in non-neoplastic colonic mucosa in patients with ulcerative colitis (UC). Macrophage migration inhibitory factor (MIF) plays a crucial role in promoting gastrointestinal inflammation characteristic of UC. The aim of this study is to explore associations between CDKN2A methylation status and MIF polymorphisms (rs755622 and rs5844572)., Methods: One hundred and fifty-nine patients diagnosed with UC were enrolled in this study. The methylation status of p14 ARF and p16 INK4a was determined by MSP; MIF genotypes were identified by PCR-SSCP., Results: We found no differences with respect to mean age, gender, clinical type (chronic continuous or relapse/remitting), or extent of disease among the patients with methylated and unmethylated p14 ARF or p16 INK4a . Carrying the rs755622 C allele indicated a significantly higher risk for p14 ARF methylation (odds ratio (OR), 2.16; 95% confidence interval (CI), 1.08-4.32; p = 0.030); similarly, carrying the rs5844572 7-repeat allele indicated a significantly higher risk for p16 INK4a methylation (OR, 2.57; 95% CI, 1.26-5.24; p = 0.0094) after an adjusted regression analysis. The carriers of the rs755662 C allele or the rs5844572 7-repeat allele were both at a significantly higher risk for methylation of both p14 ARF and p16 INK4a when compared to the cohort in which neither of the genes were methylated (OR, 2.70; 95% CI, 1.22-6.01; p = 0.015 and OR, 2.87; 95% CI, 1.25-6.62; p = 0.013, respectively). Additionally, carrying rs755622 C allele was significantly associated with CIHM in chronic continuous of clinical type and total colitis (OR, 25.9; 95% CI, 2.55-262.6; p = 0.0059 and OR, 4.38; 95% CI, 1.12-17.2; p = 0.034, respectively), and carrying 7-repeat allele of rs5844572 was significantly associated in chronic continuous type (OR, 14.5; 95%CI, 1.46-144.3; p = 0.022)., Conclusions: Taken together, our findings suggest that MIF genotypes associated with inflammation may also be involved in promoting carcinogenesis via CDKN2A hypermethylation in patients diagnosed with UC.

Aim: To investigate the associations between LINE1 methylation, an indicator for genome-wide hypomethylation, molecular and clinicopathological characteristics of gastric cancer (GC) patients. Patients & methods: LINE1 methylation statuses were examined in paired cancerous, non-neoplastic mucosa from 217 GC and gastric mucosa from separate group of 224 noncancer patients. CpG island methylator phenotype, TP53 and KRAS mutation, MLH1 methylation status and promoter hypermethylation of GC related and H. pylori -related genes were examined. Results: Lower LINE1 methylation was observed in primary GC compared with non-neoplastic gastric mucosa and associated with CpG island methylator phenotype, TP53 mutation, MLH1 methylation and promoter hypermethylation of GC related and H. pylori -related genes. Conclusion: Lower LINE1 methylation correlates specific molecular subtypes and promoter hypermethylation in GC.

Genome-wide association study identified two functional SNPs associated with gastric cancer especially the diffuse type. The first was a polymorphism (rs2294008) in prostate stem cell antigen ( PSCA ), and the other was a polymorphism (rs4072037) in mucin 1 ( MUC1 ). DNA methylation is associated with gastric cancer and Helicobacter pylori ( H. pylori )-induced gastritis, while hypermethylation of promoter CpG island (CGI) is a common characteristic of enlarged-fold gastritis induced by H. pylori , a risk factor of diffuse-type gastric cancer. We evaluated the association between PSCA and MUC1 polymorphisms with H. pylori- -related promoter CGI methylation in the nonneoplastic gastric mucosa. PSCA rs2294008 C/T and MUC1 rs4072037 A/G polymorphisms were genotyped in 410 cancer-free subjects in relation to promoter CGI methylation status of three candidate genes, of which the methylation status is associated with H. pylori infection ( IGF2, MYOD1 , and SLC16A12 ). Methylation levels of all three genes were significantly higher in subjects with PSCA rs2294008 T/T compared with the PSCA rs2294008 C/C (all P < 0.05). Such associations were more enhanced in H. pylori -positive subjects (all P < 0.01). The multivariate analysis demonstrated that PSCA C/T [OR, 2.37; 95% CI (confidence interval), 1.06-5.29; P = 0.035] and T/T genotypes (OR, 3.2; 95% CI, 1.41-7.25; P = 0.005) were significantly associated with methylation-high gastric mucosa as independent factors. MUC1 rs4072037 A/G polymorphism was not associated with methylation status of all three genes. PSCA C/T and T/T genotypes are associated with H. pylori -related promoter DNA methylation in the gastric mucosa. Impact: Our observations provided the evidence that PSCA polymorphism influence the susceptibility to gastric cancer through DNA methylation induction., (©2019 American Association for Cancer Research.)

Molecular irreversibleness with Helicobacter pylori (H. pylori) infection might have a role in gastric tumorigenesis after H. pylori eradication. We performed comprehensive DNA methylation profiling of gastric mucosa after H. pylori eradication with or without gastric cancer. Using four different groups of biopsies obtained from gastric body without history of H. pylori infection (Hp-), gastric body without cancer after H. pylori eradication (cancer-free body), gastric body with early gastric cancer diagnosed after H. pylori eradication (EGC body) and their paired samples from adjacent mucosa of cancer (EGC ADJ), methylation status of five candidate genes (MYOD1, SLC16A12, IGF2, RORA and PRDM5) was examined by the bisulfite pyrosequencing. An Infinium Methylation EPIC BeadChip array was also used to characterize the methylation status of greater than 850,000 CpG sites. The EGC ADJ group showed highest methylation levels of five candidate genes among the four groups of biopsies. In the gastric body (cancer-free body + EGC body), methylation levels were significantly decreased in patients with longer period after eradication, while such association was not observed in EGC ADJ group. Hyper methylated samples were associated with shorter telomere, an indicator for rapid cell turnover, and higher DNMT1 protein expression, an enzyme related to methyl transfer reaction. The genome-wide methylation analysis demonstrated strikingly higher methylation levels especially at CpG islands in the EGC ADJ group. Exclusively hypermethylated promoter CpG islands in the same group frequently coded zinc finger proteins. Our data show that DNA methylation accumulation is associated with molecular irreversibleness and gastric carcinogenesis after H. pylori eradication., (© 2018 UICC.)

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.

Residual DNA methylation in the gastric mucosa after Helicobacter pylori (H. pylori) eradication may have a role in gastric carcinogenesis. We examined the association between morphologic features and promoter methylation status of non-neoplastic gastric mucosa especially after H. pylori eradication. A total of 140 gastric specimens from 99 participants who had at least 6 months of post-eradication period were examined. The magnifying narrow-band imaging (NBI) endoscopic feature of gastric mucosa was divided into two types: restored-small, round pits, accompanied with honeycomb-like subepithelial capillary networks; atrophic-well-demarcated oval or tubulovillous pits with clearly visible coiled or wavy vessels. Methylation status of five candidate genes (MYOD1, SLC16A12, IGF2, RORA, and PRDM5) were examined by bisulfite pyrosequencing. The atrophic type, informative endoscopic features of intestinal metaplasia, demonstrated higher methylation levels in all five genes compared to the restored type (all P < 0.0001). In the restored type, methylation levels were significantly lower among the samples with longer post-eradication period (for all genes, P < 0.0001), which was not observed in atrophic type (for all genes, P > 0.1). Multivariate analysis demonstrated that atrophic type or presence of intestinal held an independent factor for hyper methylation (odds ratio: 24.69, 95% confidence interval: 6.95-87.76, P < 0.0001). The atrophic type by the magnifying NBI and presence of intestinal metaplasia are the morphologic characteristics of residual DNA methylation of after H. pylori eradication, regardless of the post-eradication period and it might be considered as the epigenetic irreversible point with H. pylori eradication., (© 2017 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.)

Introduction: Aberrant DNA methylation frequently occurs in the inflammatory mucosa in ulcerative colitis (UC) and is involved in UC-related tumorigenesis. We performed comprehensive DNA methylation profiling of the promoter regions of the inflamed rectal mucosae of patients with UC., Design: The methylation status of the promoter CpG islands (CGIs) of 45 cancer/inflammation or age-related candidate genes and the LINE1 repetitive element were examined in the colonic mucosae of 84 cancer-free patients with UC by bisulfite pyrosequencing. Methylation status of selected genes (DPYS, N33, MIR1247, GSTP1, and SOX11) was also determined in 14 neoplastic lesions (5 with high-grade dysplasia and 9 with carcinoma) and 8 adjacent tissues derived from 12 patients. An Infinium HumanMethylation450 BeadChip array was used to characterize the methylation status of >450,000 CpG sites for 10 patients with UC., Results: Clustering analysis based on the methylation status of the candidate genes clearly distinguished the inflammatory samples from the noninflammatory samples. The hypermethylation of the promoter CGIs strongly correlated with increased disease duration, which is a known risk factor for the development of colon cancer. Genome-wide methylation analyses revealed a high rate of hypermethylation in the severe phenotype of UC, particularly at the CGIs. Exclusively hypermethylated promoter CGIs in the severe phenotypes were significantly related to genes involved in biosynthetic processes, the regulation of metabolic processes, and nitrogen compound metabolic processes., Conclusion: Our findings suggest the potential utility of DNA methylation as a molecular marker and therapeutic target for UC-related tumorigenesis.

Background: Telomere length shortening in Helicobacter pylori (H. pylori) infected gastric mucosa constitutes the earliest steps toward neoplastic transformation. In addition to this genotoxic changes, epigenetic changes such as promoter CpG island (PCGI) methylation are frequently occurred in H. pylori infected gastric mucosa. The aim of this study was to investigate a potential link between H. pylori related PCGI methylation and telomere length shortening in the human gastric mucosa., Methods: Telomere length was measured in non-neoplastic gastric mucosa from 106 cancer-free subjects. To identify H. pylori related PCGI methylation, bisulfite pyrosequencing was used to quantify the methylation of 49 PCGIs from 47 genes and LINE1 repetitive elementResults: We identified five PCGIs (IGF2, SLC16A12, SOX11, P2RX7 and MYOD1), which the methylation is closely associated with H. pylori infection. Hypermethylation of all these PCGIs was associated with development of pathological state from normal to mild, active, and atrophic gastritis (P<0.001) and lower pepsinogen I/II ratio (P<0.05), an indicator for gastric mucosal atrophy. Telomere shortening was significantly associated with mean Z score methylation of five PCGIs (R=-0.39, P<0.0001) and four of these locus (IGF2: R=-0.35, P=0.0003, SLC16A12: R=-0.35, P=0.0002, P2RX7: R=-0.29, P=0.003, and MYOD1: R=-0.33, P=0.0005). Multivariate analysis revealed that telomere shortening held an increased risk for hypermethylation (odds ratio: 1.71, 95% confidence interval: 1.11-2.63, P=0.016)., Conclusion: Potential link between H. pylori related PCGI methylation and telomere shortening emphasize the importance of genotoxic-epigenetic interaction in the pathological state of H. pylori infected gastric mucosa., Competing Interests: We declare that we have no conflicts of interest.

Background: Epithelial-to-mesenchymal transition (EMT) is a phenomenon that allows the conversion of adherent epithelial cells to a mesenchymal cell phenotype, which enhances migratory capacity and invasiveness. Recent studies have suggested that EMT contributes to the pathogenesis of ulcerative colitis (UC). We investigated the promoter DNA methylation status of EMT-related genes in the colonic mucosa in UC., Methods: Colonic biopsies were obtained from the rectal inflammatory mucosa of 86 UC patients and the non-inflammatory proximal colonic mucosa of 10 paired patients. Bisulfite pyrosequencing was used to quantify the methylation of 5 candidate CpG island promoters (NEUROG1, CDX1, miR-1247, CDH1, and CDH13) and LINE1., Results: Using an unsupervised hierarchical clustering analysis, inflamed rectal mucosa was well separated from mucosa that appeared normal. The CDH1 and CDH13 promoters were significantly associated with patient age (p = 0.04, 0.03, respectively). A similar trend was found between those genes and the duration of disease (CDH1: p = 0.07, CDH13: p = 0.0002, mean of both: p<0.00001). Several positive associations were found between hypermethylation and severe clinical phenotypes (CDX1 and miR-1247 and a refractory phenotype: p = 0.04 and 0.006, respectively. miR-1247 and CDH1 hyper methylation and a more severe Mayo endoscopic subscore: miR-1247: p = 0.0008, CDH1: p = 0.03, mean of both: p = 0.003). When the severe clinical phenotype was defined as having any of five phenotypes (hospitalized more than twice, highest Mayo endoscopic subscore, steroid dependence, refractory, or a history of surgery) miR-1247 hypermethylation was associated with the same phenotype (p = 0.008)., Conclusions: Our data suggest that variability in the methylation status of EMT-related genes is associated with more severe clinical phenotypes in UC.

Background: The neurochemical serotonin (5-HT) is an important signaling molecule in the gastrointestinal motor and sensory functions. A key regulator of 5-HT levels is the transmembrane serotonin transporter (5-HTT; SLC6A4) that governs the reuptake of 5-HT. Recent studies have indicated 5-HTT expression may be regulated by epigenetic mechanisms. We investigated DNA methylation status of SLC6A4 gene in the gastric mucosa from functional dyspepsia (FD) because of their potential role in dyspeptic symptoms., Methods: Endoscopic gastric biopsies were obtained from 78 subjects with no upper abdominal symptoms and 79 patients with FD. Bisulfite Pyrosequencing was carried out to determine the methylation status of promoter CpG islands (PCGIs), promoter non-CpG islands (PNCGIs) and gene body non-CpG islands (NPNCGIs) in the SLC6A4 gene. Gene expression was examined by real-time PCR., Results: In overall, methylation level of PCGIs was significantly lower in FD compared to control subjects (p = 0.04). On the other hand, methylation level of NPNCGIs was significantly higher in FD compared to control subjects (p = 0.03). Lower methylation level in PNCGIs was highlighted in the patients with PDS (p = 0.01), while higher methylation level in NPNCGIs was more prominent in the patients with EPS (p = 0.017). Methylation levels of PCGIs and PNCGIs were inversely correlated, while methylation levels of NPNCGIs was positively correlated with SLC6A4 mRNA levels in FD patients., Conclusions: Our data suggest that change in DNA methylation pattern of SLC6A4 in the gastric mucosa may have a role for developing FD. A role of epigenetics for developing FD needs to be further evaluated.

Whole blood DNA methylation analysis has been proposed to be a risk marker for cancer that can be used to target patients for preventive interventions. To test this, we examined whole blood DNA methylation of 16 CpG island promoters and LINE1 repetitive element in patients with gastric cancer and control subjects. Bisulfite pyrosequencing was used to quantify the methylation of 14 CpG island promoters (MINT25, RORA, GDNF, CDH1, RARAB2, ER, CDH13, MYOD1, SFRP1, P2RX7, SLC16A12, IGF2, DPYS, and N33) and LINE1 from 72 patients with gastric cancer, 67 control, and 52 healthy young individuals. Quantitative methylation-specific real-time PCR was also conducted for 3 CpG island promoters (MINT25, MYO3A, and SOX11). Among all sites tested, only a marginal increase in the methylation of the SFRP1 promoter was observed in the blood of patients with gastric cancer when compared with the control group (11.3 % vs 10.5%; age-adjusted P value: P = 0.009), and this association was also seen in a validation set of 91 patients with gastric cancer (11.5% vs 10.5%; age-adjusted P value: P = 0.001). The methylation of 9 sites (GDNF, CDH1, RARAB2, CDH13, MYOD1, SFRP1, SLC16A12, DPYS, N33, and LINE1) and their mean Z score was correlated with higher age (R = 0.41, P < 0.0001) and marginally with telomere shortening (R = -0.18, P = 0.01) but not with gastric cancer risk (other than SFRP1 methylation). Variability in whole blood DNA methylation of cancer markers is primarily associated with aging, reflecting turnover of white blood cells, and has no direct link to gastric cancer predisposition. SFRP1 methylation in whole blood may be associated with gastric cancer risk.

Background: Aberrant methylation patterns in CpG island are known to be influential in gene silencing. Histamine plays important physiological roles in the upper gastrointestinal tract and acts via the H2 receptor. We report an investigation into the effect of HRH2 promoter polymorphism (rs2607474 G > A) on the methylation of DAPK and CDH1., Methods: Non cancerous gastric mucosa samples were obtained from 115 subjects with gastric cancer (GC) and 412 non-cancer subjects (non-GC). Methylation status of genes was determined by MSP. The genotyping of rs2607474 was performed by PCR-SSCP., Results: Methylation of DAPK and CDH1 was observed in 296 and 246 subjects, respectively. The frequency of CDH1 methylation in the subjects with GC was significantly lower in cancer lesion than in non cancerous mucosa, whereas that of DAPK methylation was not different. The allelic distribution of rs2607474 was 401GG, 119GA and 7AA. The GG homozygote was associated with a significantly increased risk for methylation of both DAPK and CDH1 (p < 0.0001 and p = 0.0009, respectively). In the non-GC subjects or more than 60 years of age, GG homozygote was more closely associated with both DAPK and CDH1 methylation. However, this genotype did not show an increased risk for the development of methylation of both genes in patients with GC. In H. pylori negative subjects, GG homozygote showed an increased risk for the methylation of both DAPK and CDH1 (p = 0.0074 and p = 0.0016, respectively), whereas this genotype was associated with an increased risk for the development of DAPK methylation in H. pylori positive subjects (p = 0.0018). In addition, in subjects older than 60 years of age, atrophy and metaplasia scores were significantly higher in the GG homozygote (p = 0.011 and p = 0.039, respectively) and a significant correlation was observed between age and atrophy or metaplasia., Conclusions: Our results suggest that rs2607474 GG homozygote confers a significantly increased risk for age- and inflammation-related DAPK and CDH1 methylation.

CpG island aberrant methylation is shown to be an important mechanism in gene silencing. The important role of NF-κB in the inflammatory response to H. pylori colonization has been indicated. We investigated the influence of NFKB1 polymorphisms, -94 ins/del (rs28362491) and -449 C>G (rs72696119), on the aberrant gene methylation under H. pylori infection. Gastric mucosal samples were obtained from sub-subjects without malignancies. Methylation status of genes (p14ARF, p16INK4a, DAPK and CDH1) was determined by methylation-specific PCR (MSP). The genotyping of NFKB1 was performed by PCR-SSCP. There was a strong allelic association between rs28362491 and rs72696119, and all H. pylori-infected -94 del/del homozygotes had a -449 GG genotype. The -94 del/del homozygosity was significantly associated with risk for development of CpG island high methylation (CIHM) (two or more gene methylations), especially DAPK and CDH1 methylations, and the number of methylated genes was significantly higher in -94 del/del homozygotes than in ins/del and ins/ins (ins carrier) H. pylori-infected elder subjects. In addition, this methylated gene number was significantly increased with age in H. pylori-infected del/del homozygotes, but not in infected ins carriers. Furthermore, the inflammation score was significantly higher in H. pylori-infected del/del homozygotes compared to ins carriers. NFKB1 -94 ins/del ATTG polymorphism (rs28362491) was significantly associated with the increased risk for the development of age-related gene methylation in non-cancerous gastric mucosa under H. pylori-induced inflammation.

Background: CpG island aberrant methylation is shown to be an important mechanism in gene silencing. The important role of IL-17 in inflammatory response to H. pylori colonization has been indicated. We investigated the influence of IL17A polymorphisms, -197 G > A (rs2275913) and *1249 C > T (rs3748067), on the methylation of DAPK and CDH1., Methods: Gastric mucosal samples were obtained from 401 subjects without malignancies. Methylation status of gene was determined by MSP. The genotyping of IL17A was performed by PCR-SSCP., Results: Methylations of DAPK and CDH1 were seen in 196 and 149 of all 401 subjects, respectively. Overall, *1249 T carrier was associated with a decreased risk for DAPK methylation, whereas -197 G > A was not. In the subjects older than 60 years old, *1249 T carrier was more strongly associated with gene methylation and -197 A carrier tended to be associated with an increased risk for CDH1 methylation. When evaluating by inflammation promoting haplotype (-197 mutant carrier with *1249 homozygote), this haplotype had a more strongly increased risk for both DAPK and CDH1 methylations in comparatively older subjects. Both atrophy and metaplasia scores were significantly increased with age in -197 A carrier or *1249 CC homozygote, whereas were not in -197 GG homozygote or *1249 T carrier. PG I/II ratio was more significantly decreased in -197 A carrier than in GG homozygote under influence of H. pylori infection., Conclusions: In -197 A allele carrier with *1249 CC homozygote, the methylations of both DAPK and CDH1 may be increased gradually, but more rapidly than the other genotypes, with age and altered gastric mucosal structure induced by H. pylori infection.

CpG island hyper methylation (CIHM) is one of the major events in gastric carcinogenesis. To evaluate the influence of host genetic factors in CIHM related carcinogenesis, we investigated the association between common polymorphisms in IL-1β and TNF-α genes, with CIHM status in the nonneoplastic gastric mucosa. Polymorphisms in the IL-1β gene (-31T>C and -511C>T) and the TNF-α gene (-857C>T) were genotyped in 385 cancer-free subjects. CIHM of four candidate genes: p16 (INK4a), p14 (ARF), E-cadherin (CDH1), and death-associated protein kinase (DAP-kinase), were determined by methylation-specific-polymerase chain reaction (MSP). CIHM high was defined as two or more CpG islands methylated. CIHM of all four genes and CIHM high were significantly associated with Helicobacter pylori infection status. In over all, significant marginal association was found between IL-1β-511 TT genotype and reduced susceptibility to CIHM of DAP-kinase (adjusted OR = 0.48, 95% CI = 0.29-0.78) and CIHM high (adjusted OR = 0.53, 95% CI = 0.32-0.86). This association was more enhanced in subjects 65 yr or younger age. We also found positive association between TNF-α-857T carrier and increased susceptibility to CIHM of CDH (adjusted OR = 1.78, 95% CI = 1.01-3.16), and CIHM high (adjusted OR = 1.86, 95% CI = 1.04-3.33) in the same generation. The mean number of CIHM was lower in subjects with IL-1β-511TT genotype, while the mean number was higher in subjects with TNF-α-857 T carrier especially in subjects 65 yr and younger patients. IL-1β-511 TT genotype is associated with reduced susceptibility to CIHM especially in younger generation. Furthermore, the TNF-α-857T carrier is associated with increased susceptibility of CIHM in the same generation., (Copyright © 2011 Wiley Periodicals, Inc.)

Background: Genetic factors, related to DNA repair or xenobiotic pathways might confer different degrees of susceptibility to gastric carcinogenesis. CpG island hyper methylation (CIHM) is a major event in gastric carcinogenesis. We evaluated the association between XRCC1, GSTP1, GSTT1 and GSTM1 polymorphisms with CIHM status in non-neoplastic gastric mucosa., Methods: XRCC1 Arg399Gln, and Arg194Trp, GSTP1 Ile104Val, and GSTT1, GSTM1 null polymorphisms were genotyped in 415 cancer free subjects, in relation to four candidate CpG (p14, p16, DAP-kinase and CDH1) loci, assessed by Methylation-Specific-Polymerase Chain Reaction (MSP). CIHM high was defined as two or more CpG islands methylated., Results:  Significant association between XRCC1 codon 399 Gln/Gln genotype and reduced susceptibility to CIHM of DAP-kinase (adjusted OR = 0.30, 95%CI = 0.13-0.71, p = .0055) and CIHM high (OR = 0.42, 95%CI = 0.19-0.97, p = .04). XRCC1 codon 399 Gin/Gln genotype also presented lower number of CIHM when compared with both Arg/Gln, and Arg/Arg + Arg/Gln genotypes (p = .02, .046, respectively) When subjects were divided according to age (>50 and <50), an association was found between GSTM1 null genotype and increased susceptibility to CIHM high in the 50 years and older generations (OR = 1.63, 95%CI = 1.01-2.62, p = .045)., Conclusion: XRCC1 codon 399 Gln/Gln genotype is associated with reduced susceptibility to CIHM especially DAP-kinase. GSTM1 null genotype may increase the susceptibility to CIHM especially in older patients. Genetic factors, related to DNA repair or xenobiotic pathways may have a role in CIHM-related gastric carcinogenesis., (© 2011 Blackwell Publishing Ltd.)

Background: CpG island hypermethylation (CIHM) in gene promoter is frequently observed in the colonic mucosa in ulcerative colitis (UC), and is strongly involved in UC-associated colorectal carcinogenesis (CRC). The influence of common single nucleotide polymorphisms (SNPs) related to inflammatory immune response on the individual susceptibility to CIHM status in the non-neoplastic rectal mucosa in UC patients was evaluated., Patients and Methods: Ten candidate SNPs, multidrug resistance 1 (MDR1) 3435 (C>T), regulated upon activation, normal T-cell expressed and secreted (RANTES)-28 (C>G), heat-shock protein (HSP)70-2 1267 (B>A), NADPH oxidase p22PHOX 242 (C>T), Toll-like receptor (TLR)2-196 to -174 (ins >del), CD14-159 (C>T), Mannan-binding lectin (MBL)2 codon 54 (G>A), tumor necrosis factor-α(TNF-α) -857 (C>T), interleukin-1β(IL-1β)-511 (C>T), and IL-1β -31 (T>C) were genotyped in 58 UC patients without neoplastic lesions, in relation to CIHM in the rectal mucosa of three candidate CpG (p14, p16 and E-cadherin: CDH1) loci, assessed by methylation-specific-polymerase chain reaction (MSP). High CIHM was defined as two or more CpG islands methylated., Results: The CD14-159TT genotype held a significantly higher susceptibility to CIHM of the p16 promoter (OR=3.82, 95%CI=1.06-13.79, p=0.04) A significant association was also found between the IL-1β-31TC genotype and reduced susceptibility to high CIHM (OR=0.14, 95%CI=0.22-0.94, p=0.04). The p22PHOX 242CT genotype and MBL2 codon 54 A carrier (GA+AA) were significantly associated with a lower mean number of CIHM (p=0.029, 0.046, respectively)., Conclusion: CD14 -159, IL-1β-31, p22PHOX 242 and MBL2 codon 54 SNPs may influence the CIHM status in the rectal mucosa of UC patients and may therefore be substantially involved in UC-associated carcinogenesis.

Background: CpG island hypermethylation of tumor suppressor genes is highly involved in gastric carcinogenesis, and enhanced cell proliferation could accelerate this process. Cyclin D1 regulates cell cycle function and may play a role in methylation-related carcinogenesis., Aims: We investigated the association between Cyclin D1 gene G870A polymorphism and the methylation status of tumor suppressor genes in gastric cancer., Methods: Polymorphisms at G870A in the Cyclin D1 gene were genotyped, and methylation status of the p14, p16, DAP-kinase, and CDH1 genes were determined by methylation-specific-polymerase chain reaction in 139 gastric cancer tissues. CIHM high was defined as three or more methylated CpG islands., Results: Although no association was found between methylation status and different stages and Lauren's subtypes, patients with CIHM of DAP-kinase showed significantly worse survival than those without (p = 0.017). In addition, the number of methylated sites was also associated with survival curves (p = 0.0397). The 870G carrier a significantly lower prevalence of CIHM high compared to the AA genotype in advanced-stage gastric cancer (adjusted OR = 0.32, p = 0.047). A weak correlation between the same genotypes and CIHM of p14 were found in the same subtype (adjusted OR = 0.32, p = 0.052). The mean methylation number was significantly lower in G carriers than in AA genotypes in advanced-stage gastric cancer (p = 0.017)., Conclusions: Genetic polymorphism of CCND1 is associated with CIHM status in gastric cancer, especially in the advanced stage, but is independent of clinico-pathological features.

We investigated the methylation status of multidrug resistance 1 (MDR1) gene promoter in noncancerous gastric mucosa in relation to gastric cancer (GC) occurrence. Methylation of the MDR1 promoter was estimated in 127 GC and 82 non-GC patients. A significant association was found between higher methylation ratio and occurrence of GC. Higher methylation ratio was also associated with occurrence of GC in both Helicobacter pylori-positive and Helicobacter pylori-negative subjects. Higher MR was also associated with Helicobacter pylori infection. Methylation status of MDR1 gene in noncancerous gastric mucosa would be useful for predicting GC occurrence.

CpG island hyper-methylation (CIHM) is one of the major events in the gastric carcinogenesis. IL-17A, -17F and MIF have a crucial role in the gastric inflammation and carcinogenesis. Recently, we showed that the genetic polymorphisms of MIF-794-CATT repeat are associated with CIHM status in the non-neoplastic gastric mucosa. Consequently, the CIHM status in the gastric cancer tissue, in relation to IL-17A (-197G>A), -17F (7488T>C), and MIF (-173G>C and -794 tetranucleotide repeats) polymorphisms was investigated. Gastric cancer tissues were obtained from 102 patients. CIHM of p14, p16, DAP-kinase and CDH1 genes were determined by methylation-specific polymerase chain reaction (MSP). CIHM high was defined as three or all CpG islands methylated. We employed the PCR-SSCP (multiplex PCR for IL-17A and -17F) method to detect the gene polymorphisms. We did not find significant association between CIHM status and IL-17F (7488T>C) and MIF (-173G>C) polymorphisms. However, concerning the IL-17A (-197G>A) polymorphism, we found that IL-17A G carrier (GG+GA) held a significantly higher risk of CIHM of p16 (OR=11.22, 95% CI=1.38-91.17, p=0.024) and CIHM high (OR=3.51, 95% CI=1.15-10.68, p=0.027). An association was also found between the 7-CATT repeat carrier (5/7 + 6/7 + 7/7) of the MIF polymorphism (-794-CATT) and reduced risk of CIHM of CDH1 (OR=0.36, 95% CI=0.14-0.92, p=0.032). No association was found between CHIM status and homozygote genotypes of each repeat (-794-CATT 5/5, 6/6, and 7/7). The present results provided evidence that the genetic polymorphisms of IL-17A, and MIF-794-CATT repeat are associated with CIHM status in the gastric cancer. Genetic polymorphisms of IL-17A, and MIF-794-CATT repeat may be involved in methylation-related carcinogenesis in the stomach.

Unlabelled: CpG island hypermethylation (CIHM) of tumor suppressor genes is one of the major events in the gastric carcinogenesis. We aimed to investigate the association between CIHM status of tumor suppressor genes and clinicopathological and morphological characteristics of gastric cancer., Patients and Methods: CIHM of p14, p16, Death-associated protein kinase (DAPK) and E-cadherin (CDH1) genes were determined by methylation-specific-polymerase chain Reaction in 146 gastric cancer tissues. CIHM-high was defined as three or more methylated CpG islands., Results: CIHM pf p14 was found in 70 (47.9%) cases, in 26 (17.8%) for p16, in 104 (71.2%) for CDH1 and in 127 (87.0%) for DAPK. CIHM-high was also found in 63 cases (43.2%). No association was found between between CIHM status and different staging, Lauren's subtypes, anatomic location, venous and lymphatic invasion, lymph node metastasis, distant metastasis, or peritoneal dissemination. However, among early gastric cancer cases, the depressed type with ulceration presented a significantly lower prevalence of CIHM of DAPK. In addition, Borrmann type IV cases presented significantly lower prevalence of CIHM-high among advanced gastric cancer. The Borrmann type IV cases also presented lower mean methylation number., Conclusion: The present results suggest that CIHM of DAPK and CIHM-high were associated with the morphological appearance of depressed type with ulceration in early gastric cancer, and Borrmann type IV advanced gastric cancer, respectively.

There have been reports showing a protective role of aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) against gastrointestinal cancers. E-cadherin (CDH1) is an adhesion molecule involved in tumour invasion/metastasis. Silencing of CDH1 by promoter CpG island methylation was shown in gastric cancer, precancerous lesion, and Helicobacter pylori-infected chronic gastritis. We investigated the methylation status of CDH1 in noncancerous gastric mucosa in chronic aspirin user, and assessed its effect on methylation-associated carcinogenesis. Gastric mucosa samples from antrum were obtained from 217 cancer-free subjects, including 37 chronic aspirin users and 180 subjects with no history of chronic or occasional intake of aspirin. Methylation-specific polymerase chain reaction (PCR), i.e., MSP, was performed for CDH1 gene promoter. In all 217 subjects, CDH1 methylation was detected for 69 subjects (31.7%). CDH1 methylation more frequently occurred in H. pylori-infection-positive subjects (P < 0.0001), while chronic aspirin users had a significantly lower risk of CDH1 methylation [nonuser versus user 36.1% versus 10.8%; odds ratio (OR) = 0.21, 95% confidence interval (CI) = 0.07-0.63, P = 0.005]. Logistic regression analysis showed that chronic aspirin use was the independent factor for lower risk of CDH1 methylation (adjusted OR = 0.21, 95%CI = 0.07-0.66, P = 0.008). Chronic aspirin use was associated with lower risk of CDH1 methylation in H. pylori-positive subjects (nonuser versus user 49.5% versus 19.0%; OR = 0.24, 95%CI = 0.08-0.76, P = 0.01). Similar trend was also found in H. pylori-negative subjects (P = 0.07). No association was found between CDH1 methylation status, and duration and dose of aspirin. Our data suggest that chronic aspirin use is associated with reduced risk of CDH1 methylation in human gastric mucosa. Aspirin may have suppressive role against methylation-related gastric carcinogenesis.

DNA methylation is one of the major events in the early process of gastric carcinogenesis and it also occurs in non-neoplastic gastric mucosa. MTHFR plays a central role in biotransformation of folate to form S-adenosylmethionine, the universal methyl donor in cells and affects DNA methylation status. We investigated the association between common functional polymorphism of MTHFR C677T and DNA methylation status in H. pylori-infected non-neoplastic gastric mucosa. For 99 gastric mucosa samples from H. pylori positive non-cancer subjects, we assessed the association between MTHFR C677T genetic polymorphism and promoter methylation status of the four candidate promoters (p14, p16, DAP-kinase, and CDH1). In most all of the subjects, weak correlation was found between the p16 promoter methylation and MTHFR 677T carriers (age, sex-adjusted OR = 2.57, P = 0.053). When subjects were divided into two groups according to age, the MTHFR T carrier held a significantly higher risk of p16 promoter methylation, especially in 66 years or older generation (sex-adjusted OR = 14.28, P = 0.02). In addition, mean number of methylated CpG cites were significantly higher in T carrier than CC genotype in the same generation (P = 0.0418). Our data suggest that MTHFR 677T carrier influences the risk of DNA methylation in gastric mucosa in the long-term outcome of the H. pylori infection.

Unlabelled: DNA methylation is one of the major events in the early process of gastric carcinogenesis and also occurs in non-neoplastic gastric mucosa. Catechol-O-methyltransferase (COMT) catalyzes the methylation of various endobiotic and xenobiotic substances, and protects DNA from oxidative damage. The association between a common functional polymorphism of COMT Val158Met and DNA methylation status in the stomach was investigated., Patients and Methods: One hundred and sixty-nine gastric mucosa samples from non-cancer patients were obtained by endoscopy. The promoter methylation status of p14 and p16 was determined by methylation-specific PCR (MSP). The COMT Val158Met polymorphism was detected by PCR-restriction fragment length polymorphism (RFLP)., Results: CpG island methylation was observed in 32.5% of the p14, and 37.9% of the p16. The methylation status of both p14 and p16 was not associated with gender or age, while p16 methylation was strongly associated with Helicobacter pylori infection (OR=4.71, 95% CI=2.35-9.46, p<0.0001). The Val/Val genotype held a significantly higher risk of p16 methylation (OR=3.27, 95% CI=1.05-10.25, p=0.0418)., Conclusion: The COMT polymorphism may influence the susceptibility to gene methylation in the gastric mucosa. The promoter CpG island of p16 gene, but not of p14 may be one of the specific regions whose methylation is closely influenced by the COMT polymorphism.

There have been reports showing a protective role of nonsteroidal anti-inflammatory drugs (NSAIDs) against gastrointestinal cancers. CpG island hyper methylation (CIHM) of tumor suppressor genes is a major event in carcinogenesis. We investigated the CIHM status of non-cancerous gastric mucosa in chronic NSAID users and non-users and assessed the effect of NSAIDs on CIHM. Gastric mucosa samples were obtained from 51 chronic NSAID users and 180 non-users. CIHM of p14(ARF), p16(INK4a), death-associated protein kinase (DAP-kinase), and E-cadherin (CDH1) genes were determined by methylation-specific PCR. CIHM high was defined as two or more CpG islands methylated. CIHM of p14, p16, CDH1, and CIHM high were lower in chronic NSAID users than in non-users (p14: non-users vs users = 32.2%vs 9.8%, P = 0.003; p16: non-users vs users = 35.0%vs 15.7%, P = 0.02; CDH1: non-users vs users = 36.1%vs 9.8%, P = 0.0009; CIHM high: non-users vs users = 44.4%vs 17.6%, P = 0.0009). NSAID use was also associated with decreased number of CIHM by anova (R = -0.32, P < 0.0001). Multivariate logistic regression analysis with adjustment for sex, age, Helicobacter pylori infection, and NSAID use revealed that NSAID use was inversely correlated with all four CIHM and CIHM high as an independent factor (p14: odds ratio [OR] = 0.17, 95% confidence interval [CI] = 0.06-0.48; p16: OR = 0.32, 95% CI = 0.14-0.75; DAP-kinase: OR = 0.45, 95% CI = 0.22-0.92; CDH1: OR = 0.18, 95% CI = 0.06-0.48; CIHM high: OR = 0.21, 95% CI = 0.09-0.49). No association was found between CIHM status and the duration or dose of NSAIDs. Chronic NSAID use suppresses CIHM in human gastric mucosa. NSAIDs may have a suppressive role against methylation-related gastric carcinogenesis.

Tryptase acting at protease-activated receptor 2 (PAR2) contributes to the pathogenesis of Inflammatory bowel diseases (IBDs). DNA methylation has been shown to be an important mechanism in gene silencing. We attempted to clarify the relationship between the promoter methylation of PAR2 and ulcerative colitis (UC). 84 UC patients enrolled in the study. UC patients were classified by disease behavior, severity and extent of disease. For rectal inflammatory mucosal specimens from all the patients, and normal terminal ileum from 23 patients, promoter methylation of PAR2 gene was quantified by digital densitographic analysis following to methylation-specific polymerase chain reaction (MSP). The mean methylation levels of the PAR2 gene in all 84 subjects was 38.4 +/- 19.6%. Although mean methylation levels in rectal inflammatory mucosa, and paired normal terminal ileum did not vary, methylation levels of PAR2 gene was significantly higher in total colitis than rectal colitis (total colitis vs. rectal colitis; 42.9 +/- 19.6% vs. 34.5 +/- 18.9%, P = 0.046). The higher methylation levels were also associated with Steroid-dependent (P = 0.002) and refractory (P = 0.007) UC. Our data suggest that PAR2 methylation status in rectal mucosa correlates with more severe disease phenotypes of UC.

Altered MDR1 expression and/or function contribute to the pathogenesis of inflammatory bowel disease (IBD). DNA methylation was shown as an important mechanism in gene silencing. We investigated DNA methylation of the MDR1 gene in ulcerative colitis (UC) and its relation to MDR1 C3435T genotypes. Eighty-three UC patients were enrolled. Methylation of MDR1 promoter was determined by methylation specific polymerase (MSP) for rectal inflammatory mucosa from all patients and normal terminal ileum from 17 patients. Promoter methylation of MDR1 gene was also quantified by digital densitographic analysis following MSP. MDR1 methylation was detected in 51 (61.4%) out of 83 patients in rectal inflammatory mucosa. Mean methylation level of MDR1 gene in rectal inflammatory mucosa was significantly higher than in normal terminal ileum (p=0.021). MDR1 methylation occurred more frequently in total colitis, and total+left side colitis, compared to rectal colitis (p=0.001, 0.013, respectively). Higher methylation levels were also associated with chronic continuous type (p=0.034) and earlier onset of disease (p=0.038). The 3435 CC+CT genotype of MDR1 was associated with more than 6-fold increased risk of MDR1 methylation, especially in UC patients with 9 years and shorter duration. Both frequency and level of MDR1 methylation were higher in UC onset at younger or in middle age with the same genotype. MDR1 methylation frequently occurred in inflammatory rectal mucosa from UC patients and was influenced by MDR1 C3435T polymorphism, especially in patients with shorter duration and younger onset.

Aberrant promoter methylation is an important mechanism for gene silencing. Inflammation-related reactive oxygens contribute to this CpG island methylation. The nuclear factor-erythroid 2-related factor 2 gene (Nrf2) is known to regulate the expression of detoxifying and antioxidant genes. We investigated the relationship between promoter polymorphisms of Nrf2 gene and the CpG island methylation in non-cancerous gastric mucosa. The study was performed in 85 subjects (46 without gastric malignancies, non-GC group, and 39 with gastric cancer, GC group). The promoter methylation status of p14(ARF), p16(INK4a) and p21(Waf1) genes was determined by methylation-specific-polymerase chain reaction. The Nrf2 gene genotypes were determined by the PCR-SSCP method. In the 85 subjects, CpG island methylation was found in 25.9% for p14, 15.3% for p16, none for p21. The frequency of the methylated genes was significantly higher in GC group than non-GC group (OR, 2.67; 95% CI, 1.10-6.49; p=0.029). In particular, the frequency of p16 gene methylation was much higher in GC group (p=0.0023). The Nrf2 -686/-684 G/G haplotype was positively associated and A/G haplotype was inversely associated with the development of CpG island methylation, especially p14 gene methylation (OR, 3.28; 95% CI, 1.26-8.59; p=0.015, and OR, 0.38; 95% CI, 0.15-0.96; p=0.040, respectively). In Helicobacter pylori (H. pylori) infected subjects, the number of -686/-684 G/G allele was positively correlated and that of A/G allele was inversely correlated to the methylation status, especially p14 methylation, by the adjusted analysis (OR, 2.90; 95% CI, 1.14-7.36; p=0.026, and OR, 0.33; 95% CI, 0.13-0.88; p=0.027, respectively). Our results suggested that the promoter polymorphisms of Nrf2 gene may affect the methylation status of tumor-related genes, especially the p14 gene, under the influence of H. pylori-induced gastric inflammation.

Background and Aim: Trypsin acting at protease-activated receptor 2 (PAR2) contributes to a progression of malignant tumors. An abnormal DNA methylation has been recognized as an important molecular mechanism for the genesis of various types of cancers. We attempted to clarify the relationship between the promoter methylation of PAR2 and gastric cancer., Method: We estimated the methylation of the PAR2 promoter in both antral non-cancerous mucosa and cancer lesions in 94 patients with gastric cancer. We employed a methylation-specific PCR method., Results: Regarding the methylation ratio (MR) of antral-non-cancerous mucosa, no significant difference was despite among gender, age and Helicobacter pylori infection status, whereas MR increased rising inflammation scores. The MR of cancer lesions was significantly lower than that of antral non-cancerous mucosa. This finding was not dependent on tumor staging, but also histological classification. In venous invasion, lymph node metastasis, or peritoneal dissemination negative cases, this significant lower MR was also seen., Conclusion: The promoter methylation of PAR2 seems to be increased with a progression of chronic inflammation and has an inhibitory effect on carcinogenesis of the stomach.

Background: Aberrant DNA methylation is one of the major events in carcinogenesis. Promoter DNA methylation is also present in various non-neoplastic tissues including gastric epithelium as age-related phenomenon, suggesting that it occurs early in the process of tumorigenesis., Aim: We aimed to clarify the relationship of aberrant DNA methylation in non-neoplastic gastric epithelia with the risk of gastric cancer, Helicobactor pylori infection, and the degree of H. pylori-induced gastritis., Methods: 89 patients enrolled in this study. The status of aberrant DNA methylation was compared in two groups of patients: 43 cases with gastric cancer (mean age 65.9 years [29-91], F:M = 0.30, intestinal type [n = 25], diffuse type [n = 18]) and 46 age- and sex-matched patients without gastric cancer (peptic ulcer diseases [n = 11], gastritis [n = 35]) as a control group. Genomic DNA was extracted directly from non-neoplastic epithelia of antral biopsies obtained by endoscopy. The promoter methylation status of the p14 and p21 genes was determined by methylation-specific-polymerase chain reaction (MSP). The promoter methylation status of the p16 gene was quantified by digital densitographic analysis following MSP. The degree of gastritis in the antrum was assessed according to the updated Sydney system. The PG I/II ratio was calculated based on the data of serum PG I and PG II levels measured by radioimmunoassay., Results: In all 89 subjects, CpG island methylation was found in 25.8% for p14, 52.8% for p16, 1.1% for p21. Among non-cancer patients, the methylation frequency of the p14 gene was significantly higher in H. pylori-positive than in H. pylori-negative patients (38.5 vs. 10.0%, p = 0.03). The mean (+/- SD) methylation levels of the p16 gene in non-neoplastic gastric epithelium was significantly higher in gastric cancer cases both in all patients and in H. pylori-positive patients (0.45 +/- 0.31 vs. 0.20 +/- 0.17; p = 0.019, 0.45 +/- 0.31 vs. 0.20 +/- 0.17; p = 0.016, respectively). The methylation level of the p16 gene was also associated with the presence of intestinal-type gastric cancer (p = 0.017). The methylation level of the p16 gene was significantly higher in patients with intestinal metaplasia (IM) than those without (p = 0.04). Furthermore, the methylation level of the p16 gene was correlated with lower PG l/ll ratio (p = 0.04). The methylation of the p21gene was found in only 1 patient with gastric cancer., Conclusions: Our data suggest that promoter of the p14 gene may be one of the specific regions whose methylation is closely associated with H. pylori infection. Methylation levels of the p16 gene seem to be accumulated in the progression of gastric mucosal atrophy and IM, and thus may be associated with the presence of gastric cancer especially for intestinal-type histopathology., (Copyright 2007 S. Karger AG, Basel.)

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 FROM AUTHOR]

Background: The neurochemical serotonin (5-HT) is an important signaling molecule in the gastrointestinal motor and sensory functions. A key regulator of 5-HT levels is the transmembrane serotonin transporter (5-HTT; SLC6A4) that governs the reuptake of 5-HT. Recent studies have indicated 5-HTT expression may be regulated by epigenetic mechanisms. We investigated DNA methylation status of SLC6A4 gene in the gastric mucosa from functional dyspepsia (FD) because of their potential role in dyspeptic symptoms. Methods: Endoscopic gastric biopsies were obtained from 78 subjects with no upper abdominal symptoms and 79 patients with FD. Bisulfite Pyrosequencing was carried out to determine the methylation status of promoter CpG islands (PCGIs), promoter non-CpG islands (PNCGIs) and gene body non-CpG islands (NPNCGIs) in the SLC6A4 gene. Gene expression was examined by real-time PCR. Results: In overall, methylation level of PCGIs was significantly lower in FD compared to control subjects (p = 0.04). On the other hand, methylation level of NPNCGIs was significantly higher in FD compared to control subjects (p = 0.03). Lower methylation level in PNCGIs was highlighted in the patients with PDS (p = 0.01), while higher methylation level in NPNCGIs was more prominent in the patients with EPS (p = 0.017). Methylation levels of PCGIs and PNCGIs were inversely correlated, while methylation levels of NPNCGIs was positively correlated with SLC6A4 mRNA levels in FD patients. Conclusions: Our data suggest that change in DNA methylation pattern of SLC6A4 in the gastric mucosa may have a role for developing FD. A role of epigenetics for developing FD needs to be further evaluated. [ABSTRACT FROM AUTHOR]

Background/Aim: We investigated the relationship of gastric cancer (GC) and CpG island hypermethylation (CIHM) in tumor suppressor genes of non-neoplastic gastric mucosa. Methods: Gastric mucosa samples were obtained from 125 GC and 180 non-GC subjects. CIHM of p14, p16, DAP-kinase and CDH1 genes were determined by methylation-specific polymerase chain reaction. High CIHM was defined as three or all methylated CpG islands. Results: Rates of CIHM of p14, CDH1, DAP-kinase, and high CIHM were significantly higher in all GC samples than non-GC samples (p14: 32.2 vs. 50.4%; OR = 1.70, 95% CI = 1.03–2.80, p = 0.04, CDH1: 36.1 vs. 84.0%; OR = 8.65, 95% CI = 14.74–15.77, p < 0.0001, DAP-kinase: 42.2 vs. 83.2%; OR = 5.98, 95% CI = 3.37–10.62, p < 0.0001, and high CIHM: 44.4 vs. 80.8%; OR = 4.40, 95% CI = 2.51–7.72, p < 0.0001). CIHM in CDH1 and DAP-kinase were associated with a greater risk of GC including all of its different subtypes. An increased number of CIHM was associated with an increased risk of all GC (1 CIHM; OR = 2.33, 95% CI = 0.82–6.64, p = 0.11, 2 CIHM; OR = 4.89, 95% CI = 1.79–13.37, p = 0.002, 3 CIHM; OR = 9.43, 95% CI = 3.20–27.78, p < 0.0001, and all CIHM OR = 24.71, 95% CI = 6.70–91.18, p < 0.0001). Three and all CIHM were closely associated with a higher risk of intestinal-type GC, Helicobacter pylori-positive infection status, male gender, and middle and older GC while 3 CIHM was closely associated with a higher risk of diffuse-type GC, H. pylori-negative infection status and younger GC. Conclusions: CIHM of CDH1 and DAP-kinase in non-neoplastic gastric mucosa corresponded to a risk of GC regardless of histological subtype, H. pylori infection status, gender and generation. An increased number of CIHM correlates with a higher GC risk including its various clinico-pathological subtypes. Copyright © 2010 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]