Fangyu Wang

Toll-like receptor 2 -196 to 174del polymorphism influences the susceptibility of Japanese people to gastric cancer.

Toll like receptors (TLR) play important roles in the signaling of many pathogen‐related molecules and endogenous proteins associated with immune activation. The –196 to –174del polymorphism affects the TLR2 gene and alters its promoter activity. We investigated the influence of the TLR2–196 to –174del polymorphism on the occurrence of non‐cardiac gastric cancer (NCGC) in a Japanese population. The study was carried out with 289 patients with NCGC, 309 non‐cancer patients with abdominal discomfort and 146 healthy controls. The –196 to –174del TLR2 polymorphism was investigated using the allele‐specific polymerase chain reaction method in all of the subjects. The –196 to –174del/del genotype of TLR2 showed a significantly higher frequency in NCGC patients than in healthy controls (adjusted odds ratio [OR] = 6.06; 95% confidence interval [CI] = 1.86–19.72). Similarly, the frequency of the –196 to –174del/del genotype was significantly higher among NCGC patients than in non‐cancer patients (adjusted OR = 2.02; 95% CI = 1.22–3.34). The same genotype was associated with an increased risk of both intestinal (OR = 2.00, 95% CI = 1.12–3.60) and diffuse‐type (OR = 2.05; 95% CI = 1.11–3.79) histopathology. There were no significant associations between TLR2 genotypes and tumor stage and anatomical location. Our data suggest that the –196 to –174del/del genotype of TLR2 may increase the risk of gastric cancer in the Japanese population. (Cancer Sci 2007; 98: 1790–1794)

Homozygous 825T Allele of the GNB3 Protein Influences the Susceptibility of Japanese to Dyspepsia

The role of genetics in the susceptibility to functional dyspepsia (FD) is not well established. Recently, two different associations were reported between FD and G-protein beta3 (GNB3) subunit gene polymorphism. We aim to clarify the association between GNB3 protein C825T polymorphism and dyspepsia in the Japanese population. Eight-nine dyspeptics and 94 nondyspeptic subjects enrolled in this study. All subjects underwent gastroscopy and patients with significant upper gastrointestinal findings were excluded. Other diseases were also excluded by face-to-face history and physical examination. GNB3 protein C825T polymorphisms were determined by polymerase chain reaction-restriction fragment-length polymorphism. H. pylori infection status was examined by histology or antibody against H. pylori. Nonsignificant correlation was found between GNB3 protein homozygous 825T and unexplained dyspepsia (ORxa0=xa01.65, 95% CI: 0.87–3.13). However, among H. pylori-negative subjects, homozygous GNB3 protein 825T significantly increased the risk of dyspepsia (16.7% versus 40.5%; CC versus TT; ORxa0=xa05.10, 95% CI: 1.21–21.43, CC versus others; ORxa0=xa03.40, 95% CI: 1.16–9.93, respectively). This significant association remained after logistic regression analysis with adjustment for sex and age (CC versus TT; ORxa0=xa05.73, 95% CI: 1.27–25.82, CC versus others; ORxa0=xa03.08, 95% CI: 1.02–9.25). No significant correlation was found between GNB3 polymorphism and any dyspeptic symptoms. Our data suggest that the homozygous 825T allele of GNB3 protein is associated with dyspepsia in the H. pylori-negative Japanese population. The role of genetics in the development of dyspepsia needs further evaluation.

A Polymorphism of microRNA 27a Genome Region Is Associated With the Development of Gastric Mucosal Atrophy in Japanese Male Subjects

Noncoding microRNAs regulate the expression of various mRNAs. We attempted to clarify the relationship between miR-27a genome polymorphism and chronic gastritis. The study was performed in 179 patients with no evidence of gastric malignancy. The severity of histologic chronic gastritis was classified according to the updated Sydney system. The frequency of miR-27a G allele was 34.6%. Although the frequencies of miR-27a G allele were increased in subjects with peptic ulcer or severe mucosal atrophy, no significant differences were seen. The miR-27a polymorphism showed an interaction with gender in relation to gastric mucosal atrophy (P=.090). In only male subjects, the miR-27a polymorphism was associated with the gastric mucosal atrophy (P=.039) and both atrophy and metaplasia scores in G/G group were significantly higher than those in the other groups. The miR-27a genome region polymorphism may be an important definitive factor to develop the gastric mucosal atrophy in Japanese male subjects.

Risk prediction of gastric cancer by analysis of aberrant DNA methylation in non-neoplastic gastric epithelium.

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.

Influence of Peroxisome Proliferator-activated Receptor (PPAR)γ Plo12Ala Polymorphism as a Shared Risk Marker for Both Gastric Cancer and Impaired Fasting Glucose (IFG) in Japanese

Activation of peroxisome proliferator-activated receptor γ (PPARγ) has been shown to inhibit the proliferation of gastric cancer cells. A common polymorphism at codon 12 of this gene (Pro12Ala) has been shown to confer protection against diabetes and colorectal cancer. We investigated the influence of PPARγ gene Plo12Ala polymorphism on the risk of gastric cancer and on the severity of Helicobacter pylori-induced gastritis as well as impaired fasting glucose (IFG) in Japanese. About 215 patients with gastric cancer (GC) and 201 patients without GC enrolled in this study. Plo12Ala polymorphism of PPARγ was investigated by PCR-RFLP in all of the subjects. The gastritis score of noncancerous antral mucosa was calculated by the updated Sydney system. The diagnosis of IFG was based on repeated evidence of serum fasting glucose (SFG) concentration of greater than or equal to 110xa0mg/dl. The Plo12Ala genotype of PPARγ showed a significantly higher frequency in GC patients than in controls (ORxa0=xa02.43; 95%CIxa0=xa01.04–5.67). In contrast, the Plo12Ala genotype held a lower risk of IFG (ORxa0=xa00.33; 95%CIxa0=xa00.13–0.83). The same genotype was associated with an increased risk of non-cardiac gastric cancer (ORxa0=xa02.39; 95%CIxa0=xa01.02–5.65), lower third gastric cancer (ORxa0=xa03.56; 95%CIxa0=xa01.31–9.71), advanced cancer (ORxa0=xa02.93; 95%CIxa0=xa01.13–7.58), and Lauren’s intestinal cancer (ORxa0=xa02.94; 95%CIxa0=xa01.13–7.66). Among 151 gastric cancer subjects, the atrophy and metaplasia scores of the antral mucosa adjacent to cancer showed a tendency to be higher in those with the12Ala allele. Our study suggests that the PPARγ Pro12Ala polymorphism may be a shared risk marker of both IFG and gastric cancer in Japanese.

Toll-like Receptor 2 (TLR) −196 to 174del Polymorphism in Gastro-duodenal Diseases in Japanese Population

Toll-like receptors (TLRs) play important roles in the signaling of many pathogen-related molecules and endogenous proteins associated with immune activation. −196 to −174del polymorphism affects the TLR2 gene and alters its promoter activity. We investigated the influence of TLR2 −196 to −174del polymorphism on the risk of gastro-duodenal diseases, on the severity of Helicobacter pylori-induced gastritis in a Japanesepopulation. The study was performed on 309 patients with abdominal discomfort and 146 healthy controls. −196 to −174del polymorphism of TLR2 was investigated by allele-specific polymerase chain reaction method in all of the subjects. Gastritis scores of antral gastric mucosa were assessed according to the updated Sydney system in H.xa0pylori-positive subjects (nxa0=xa0156). Patients with abdominal discomfort was consisted of 80 gastric ulcers (25.9%), 38 duodenal ulcers (12.3%), five gastricxa0+xa0duodenal ulcers (1.6%), 105 patients with gastritis (34.0%) and 81 normal healthy stomachs (26.2%). We did not find any association between TLR2 polymorphism and risk of gastric ulcer, duodenal ulcer, gastric and duodenal ulcer and gastritis compared to healthy controls. However, the TLR2−196 to −174ins allele was associated with severity of intestinal metaplasia in more than 60xa0years of ages (Pxa0=xa00.02). The same allele also increased the risks of developing more severe gastric mucosal atrophy and intestinal metaplasia in female subjects (Pxa0<xa00.05, Pxa0=xa00.07 respectively). No association was observed between TLR2 polymorphism and severity of neutrophil and mononuclear cell infiltration. Our data suggest that the TLR2−196 to −174ins allele was associated with more severe intestinal metaplasia in patients older than was correlated with severity of gastric mucosal atrophy and intestinal metaplasia in female subjects.

Genetic Polymorphisms of Molecules Associated with Innate Immune Responses, TRL2 and MBL2 Genes in Japanese Subjects with Functional Dyspepsia.

Inflammatory changes in the gastric mucosa are commonly observed in Japanese patients with functional dyspepsia (FD). However, detailed data regarding the possible association between the genetic factors of inflammation related molecules and FD are not available. Toll like receptor 2 (TLR2) and mannan-binding lectin (MBL) protein play important roles in the innate immune activation. We aimed to clarify the association between common polymorphisms of TLR2 and MBL2 genes with FD in Japanese subjects. TLR2 −196 to −174 del and MBL2 codon54 G/A polymorphisms were genotyped in 111 FD patients according to Rome III criteria and 106 asymptomatic controls. Non-significant correlation was found between TLR2 and MBL2 polymorphisms with FD. However, in Helicobacter pylori (H. pylori) positives, we found significant inverse association between TLR2 −196 to −174 del carrier and FD among H. pylori positive subjects (Adjusted odds ratio (OR) = 0.48, 95% confidence interval (CI) = 0.23–0.996, p = 0.0488). We also found significant inverse association between the same genotype with postprandial distress syndrome (PDS) among H. pylori positive subjects (Adjusted OR = 0.22, 95% CI = 0.07–0.69, p = 0.0099). Our data suggest that TLR2 −196 to −174 del carriers’s status but not MBL2 codon54 G/A is inversely related to the risk with FD in H. pylori-infected subjects.

Association of endoscopic appearances with dyspeptic symptoms

BackgroundThe relationship between endoscopic appearances such as endoscopic gastritis and duodenitis and dyspeptic symptoms has not been clearly demonstrated. We aimed to clarify the association of endoscopic appearances with Helicobacter pylori infection, histological severity of gastritis, and dyspeptic symptoms in a Japanese population.MethodsWe enrolled 87 dyspeptic and 93 nondyspeptic subjects in this study. All subjects underwent gastroscopy, and patients with active peptic ulcer disease, reflex esophagitis with erosion, polyps >1 cm, or cancer were excluded. Endoscopic appearances in patients with dyspeptic symptoms and in those without were assessed retrospectively on the basis of endoscopic images. The degree of atrophy by the Kimura-Takemoto classification system was also assessed. Helicobacter pylori infection status was examined by histology or antibody against H. pylori. Histological severity of inflammation and glandular atrophy in the antrum were assessed according to the updated Sydney System. The odds ratio (OR) and 95% confidence interval (CI) were calculated by logistic regression using the variables age, sex, H. pylori infection status, and all endoscopic appearances.ResultsThe degree of atrophy tended to be lower among dyspeptic patients (P = 0.06). Among all endoscopic appearances, the liner redness (friability) in the antrum (OR = 3.90, 95% CI = 1.20−12.64) and duodenal ulcer (DU) scarring (OR = 3.41, 95% CI = 1.08−10.79) were independently associated with dyspepsia. Histological severity of inflammation and glandular atrophy were not associated with dyspeptic symptoms. Also, no correlation was found between endoscopic appearances and any of the different subgroups of dyspeptic symptoms. Patients with friability in the antrum and DU scar, which correlated with dyspeptic symptom showed some of communal symptoms such as epigastric pain, epigastric discomfort, hypochondriac pain, early satiation/postprandial fullness, and belching, but they differed considerably with respect to H. pylori positivity and the histological severity of gastritis.ConclusionsSome endoscopic appearances such as friability in the antrum and DU scarring may be associated with dyspeptic symptoms, and endoscopic appearances may be useful markers to perform clinical implementation reflecting an individual’s pathophysiology of dyspeptic symptoms.

Association of polymorphism of the p22PHOX component of NADPH oxidase in gastroduodenal diseases in Japan

Objective. Superoxide has been implicated in the pathogenesis of Helicobacter pylori-related diseases through inflammation. NADPH oxidase, a major source of superoxide generation, plays a critical role in H. pylori-related gastric inflammation. The aim of this study was to clarify the effect of the p22PHOX C242T polymorphism, an essential component of NADPH oxidase in the risk of gastroduodenal diseases, on the severity of H. pylori-induced gastritis in a Japanese population. Material and methods. The study comprised 436 patients attending the Endoscopy Center of Fujita Health University Hospital. The p22PHOX C242T polymorphism was determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Gastritis scores of antral gastric mucosa were assessed according to the updated Sydney system. Results. The 436 patients represented 106 gastric ulcers (24.3%), 48 duodenal ulcers (11.0%), and 282 non-ulcer subjects (64.7%). No association was found between p22PHOX polymorphism and the risk of ulcer diseases compared to non-ulcer subjects. However, among H. pylori-positive subjects, the degree of intestinal metaplasia tended to be lower in 242T carriers aged more than 60 years (p=0.0488). The same allele also decreased the risk of developing a more severe intestinal metaplasia in H. pylori-positive female subjects (p=0.0441). Conclusions. Our data suggest that the p22PHOX 242T allele is associated with a reduced risk of developing a more severe intestinal metaplasia in subjects older than 60 years of age and in female subjects with H. pylori infection.

Promoter hypomethylation of protease-activated receptor 2 associated with carcinogenesis in the stomach.

Background and Aim:u2002 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.