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.
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.
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.
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.
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.
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.
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.
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.
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.
Abstract
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.
A complex interaction of genetic and environmental factors is relevant in gastric carcinogenesis. Previous studies reported that the expression of RANTES is enhanced in Helicobacter pylori-infected ...gastric mucosa. Elevated serum level of RANTES in gastric cancer patients was also reported. We aimed to clarify the effect of RANTES promoter polymorphism on the risk of gastric cancer (GC) in a Japanese population.
A total of 191 GC and 335 non-cancer patients including H. pylori-positive gastritis (n=180) and H. pylori- negative healthy stomach (n=155) were genotyped for polymorphisms at -28 C/G in the RANTES gene promoter region.
RANTES promoter genotype distributions were not significantly different among GC, overall non-cancer patients, healthy stomach and gastritis. In the comparison of genotype frequency between GC and healthy stomach, only a weak correlation was found between -28G/G genotype and GC in individuals more than 70 years of age (odds ratio (OR)=7.65, 95% confidence interval (CI)=0.78-75.0, p=0.07), with advanced stage (OR=6.58, 95% CI=0.72-59.77, p=0.07), lymph node metastasis (OR=7.20, 95% CI=0.79-65.46, p=0.06) and peritoneal dissemination (OR=10.93, 95% CI=0.96-124.64, p=0.07).
The effect of -28 C/G polymorphism in the RANTES gene promoter on GC development may not to be very strong. The role of RANTES promoter polymorphism in gastric carcinogenesis needs further evaluation.
Introduction: A complex interaction of host genetic and environmental factors may be relevant in the development of Helicobacter pylori-related gastric diseases. Small, non-coding RNA molecules, ...called microRNAs (miRNAs), are thought to have functions as either tumor suppressors or oncogenes. Common single-nucleotide polymorphisms (SNPs) in miRNAs may change their property through altering miRNA expression and/or maturation, and thus they may have an effect on thousands of target mRNAs, resulting in diverse functional consequences. We evaluated the associations of three select SNPs (rs11614913, rs2910164, and rs3746444) in pre-miRNAs (hsa-mir-196a2, hsa-mir-146a, and hsamir-499) with the risk of gastric cancer (GC) and peptic ulcer diseases, and with the severity of H. pylori-induced gastritis in central Japan. Methods: The rs11614913 (C > T), rs2910164 (G > C), and rs3746444 (A > G) SNPs were genotyped in a total of 1,249 subjects including 552 GC, 214 ulcer including 141 gastric ulcer (GU), 73 duodenal ulcer (DU), and 483 non-ulcer subjects. The degree of histological gastritis in the uninvolved mucosa was classified according to the updated Sydney System in 579 cases. The serum pepsinogen levels were measured by radioimmunoassay in 204 cases. Results: The rs2910164 CC genotype held a significantly higher risk of GC when compared to non-cancer subjects (overall non-cancer vs. GC; adjusted OR = 1.30, 95%CI = 1.02-1.66, p = 0.03). Similarly, the rs2910164 C carrier was associated with higher risk of GC when compared to both non-cancer and non-ulcer subjects (overall non-cancer vs. GC; adjusted OR = OR = 1.39, 95%CI = 1.00-1.93, p = 0.05, non-ulcer vs. GC; adjusted OR = 1.57, 95%CI = 1.09-2.27, p = 0.016). The rs2910164 CC genotype was associated with non-cardia (OR = 1.29, 95%CI = 1.01-1.64, p = 0.04) and upper-third anatomical locations (OR = 1.76, 95%CI = 1.02-3.02, p = 0.04), diffuse type histopathology (OR = 1.41, 95%CI = 1.01-1.96, p = 0.04), and advanced stage (OR = 1.56, 95%CI = 1.15-2.12, p = 0.004) compared to non-cancer subjects. In addition, the rs2910164 C carrier was associated with non-cardia (OR = 1.61, 95%CI = 1.11-2.34, p = 0.01) middle-third anatomical locations (OR = 1.62, 95%CI = 1.03-2.55, p = 0.04), and diffuse type histopathology (OR = 1.69, 95%CI = 1.02-2.79, p = 0.04) compared to non-ulcer subjects. The rs11614913 TT genotype was associated with a higher degree of mononuclear cell infiltration in the antrum by the Mann-Whitney U test (TT vs. others, 1.69 + or - 0.78 vs. 1.46 + or - 0.82. p = 0.002) and this association was confirmed by logistic regression analysis with adjustment for age, sex, and H. pylori infection (inflammation score 0-1 vs. 2-, OR = 1.62, 95%CI = 1.05-2.49, p = 0.03). No association was found between the three SNPs and risk of ulcer diseases and serum pepsinogen levels. Conclusions: The rs2910164 (G > C) SNP in the hsa-mir-146a is associated with susceptibility to GC. In addition, the rs11614913 (C > T) SNP in the hsa-mir-196a2 is associated with the degree of H. pylori-induced mononuclear cell infiltration. This is the first evidence that SNPs in the pre-miRNAs are associated with H. pylori-related gastric diseases in Japan.
Introduction: In Western countries, the response of gastric cancer (GC) to chemotherapy is evaluated according to the response evaluation criteria in solid tumors (RECIST). We investigated the ...clinical significance of evaluating primary lesions by endoscopy in patients with GC receiving chemotherapy. Methods: 192 advanced GCs performing chemotherapy were included. RECIST and endoscopy-based response evaluations were performed after 2 courses of first line chemotherapy. Complete response (CR) and partial response (PR) based on RECIST were defined as RECIST responders. Endoscopic responders were defined as a clear reduction of primary lesions in endoscopic imaging, assessed by experienced endoscopists by the consensus manner. Overall survival (OS) and progression-free survival (PFS) were compared using log-rank test. Result: 78 patients performed gastrectomy after chemotherapy (neoadjuvant chemotherapy) and remaining cases performed chemotherapy alone. The majority of the cases (n = 178, 93 %) received S-1 based chemotherapy as the first line treatment. 55 (29 %) and 91 (47 %) cases were considered to be RECIST and endoscopic responders, respectively. Endoscopic evaluation was more clearly associated with OS and PFS compared to RECIST-based evaluation by the log-rank test (p < 0.0001 vs. 0.01 and p < 0.0001 vs. 0.008, respectively). The association was more striking among patients performing neoadjuvant chemotherapy (p < 0.0001 vs. 0.15 and p < 0.0001 vs. 0.1, respectively). Multivariate survival analysis using Cox's regression model revealed that endoscopic non-responders were the independent predictive factor, being more strongly associated with lower OS when compared to RECIST non-responders (p < 0.0001 vs. 0.02). More advanced T, N stages and cases who had peritoneal dissemination were significantly associated with endoscopic non-responders (all p values <0.01). Conclusion: Evaluating primary lesions by endoscopy can better predict OS and PFS in patients with GC receiving chemotherapy.
Introduction: CpG island hyper methylation (CIHM) status provides a distinct clinicopathological feature of gastric cancer (GC). We investigated the association between the CIHM of four highly ...susceptible loci and GC. Methods: Paired samples of GC tissues and adjacent normal mucosa in GC patients as well as control samples from 180 non-GC subjects were obtained. CIHM of p14, p16, CDH1 and DAP-kinase (DAPK) genes were determined by Methylation Specific PCR. CIHM high was defined as when three or all CpG islands methylated. Result: Rates of CIHM of p14, CDH1, DAPK, and high CIHM in non-cancer mucosa were significantly higher in GC patients than in non-GC patients (p14: 32.2 vs. 50.4%; OR: 1.70, 95% CI 1.03-2.80, CDH1: 36.1 vs. 84.0%; OR: 8.65, 95% CI 14.74-15.77, DAPK: 42.2 vs. 83.2%; OR: 5.98, 95% CI 3.37-10.62 and high CIHM: 44.4 vs. 80.8%; OR: 4.40, 95% CI 2.51-7.72). CIHM in CDH1 and DAPK were associated with a greater risk of GC including all of its different subtypes. In comparison of a paired sample in GC patients, frequencies of CIHM of p16, CDH1, and high CIHM were decreased in cancer tissues than in normal mucosa. Mean methylation number in the cancer tissue was also decreased. Decreased CIHM of p14, CDH1, and high CIHM were associated with advanced stage, lymphatic invasion, venous invasion, lymph node metastasis, peritoneal dissemination and distant metastasis. When dividing GC by mean methylation number into Type A (increased methylation number in GC tissues), Type B (no change in methylation number) and Type C (decreased methylation number in GC tissues), aggressive phenotypes of GCs presented lower prevalence of Type A, and higher prevalence of Type B and C. Conclusion: CIHM in non-neoplastic mucosa corresponded to a risk of GC, while it is suggested that CIHM may occur earlier in the gastric mucosa, then decrease during GC development and progression.
Heat-shock protein (HSP) 70 plays essential roles in cellular response to a variety of environmental stresses or unfavorable conditions. A to G transition at the 1267 position of the HSP70-2 gene ...confers different levels of HSP70 mRNA expression. We aimed to clarify the effect of HSP70-2 polymorphism on the risk of premalignant condition, on the degree of acute or chronic inflammation in the stomach.
A total of 378 individuals participated in this study. Restriction fragment length polymorphism analysis was performed for polymorphisms at 1267 of HSP70-2 gene. Prevalence of intestinal metaplasia was investigated histologically and the degree of histological gastritis in the antrum was classified according to the updated Sydney System.
Although a direct association was not observed between HSP70-2 polymorphism and prevalence of intestinal metaplasia, a significant association was found between the BB genotype and lower metaplasia score in individuals who were Helicobacter pylori (H. pylori) positive and aged 60 years or older (BB vs. A carriers; 0.84+/-0.95 vs. 1.23+/-1.01, p=0.0197). When individuals were divided into 3 groups according to the severity of gastric mucosal atrophy: non-atrophic gastritis (NA) group (atrophy score=0 and metaplasia score=0), severe atrophic gastritis (SA) group (atrophy score > or =2 or metaplasia score > or =2), and mild atrophic gastritis (MA) group (all others), the BB genotype was associated with a lower risk of severe atrophy in the SA sub-group (adjusted odds ratio=0.37, 95% confidence interval =0.16-0.84, p=0.0172).
The BB genotype of HSP70-2 gene is associated with a reduced risk of gastric pre-malignant condition in H. pylori-infected older individuals.
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