Risk Of Gastric Carcinoma Research Articles

Signet-Ring Cell Carcinoma Arising in the Gastric Stump after Duodenopancreatectomy for Ductal Adenocarcinoma of the Pancreas: A Case Report

The development of malignancy in the gastric stump following surgery for peptic ulcer disease is well recognized. There are also few reports on carcinomas occurring after surgery for malignant gastric disease. However, carcinoma of the gastric stump after duodenopancreatectomy is extremely rare. We describe what we believe to be an unusual case of signet-ring cell carcinoma of the gastric stump developing at the anastomotic site 5 years after duodenopancreatectomy for ductal adenocarcinoma of the pancreatic head. We performed remnant gastrectomy and Roux-en-Y gastrojejunostomy as a curative resection. This experience clearly underlies that g astric stump carcinoma (GSC) may mimic metastatic disease recurrence leading to diagnostic confusion after surgery for malignancy. Although an increased risk of gastric stump carcinoma after pancreatoduodenectomy for pancreatic cancer has not been established, the possibility of such a complication should be kept in mind when evaluating patients after gastric resection who present with symptoms of metastatic disease recurrence years after the primary operation. Investigations should be independent of the entity of the primary disease or its localization, since GSC may well be amenable to surgical cure as demonstrated in the presented case. Outpatient follow up results of the last four years indicated no recurrence in this case.

Association of COX-2 genetic polymorphisms and H pylori infection with gastric cancer in high-incidence Hexi area of Gansu Province in China

AIM: To investigate the relationship among cyclooxygenase-2 (COX-2) polymorphisms (COX-2-899G＞C and COX-2 codon587G＞A), H pylori infection and susceptibility to gastric cancer in high-incidence Hexi area of Gansu, Province in China. METHODS: Blood samples were collected from 140 patients with gastric carcinoma and 125 nor mal persons in Hexi area of Gansu Province. Ge nomic DNA was extracted by phenol chloroform method and polymorphisms of COX-2-899G＞C (G to C) and codon 587G＞A (G to A) were genotyped by PCR-TaqMan. For detection of H pylori infection, Warhin-starry staining was used. RESULTS: Three kinds of COX-2-899G＞C genotypes were found, including GG, GC and CC. Their frequencies in gastric cancer patients were 72.9%, 21.4%, 5.7% and their frequencies in the normal controls were 84.0%, 12.8%, 3.2%, respectively. COX-2-899C carriers had an increased risk of gastric carcinoma (OR=1.956, 95%CI: 1.067-3.586).COX-2 587codonG＞A included three genotypes: G/G, G/A and A/A. Their frequencies in the cancer patients were 86.4%, 11.4%, 2.2%, and in the normal controls were 89.6%, 9.6%, 0.8%, respectively. However, No significant differences of COX-2 587codon G＞A polymorphisms were observed between the cancer patients and the normal controls in each genotype. The rate of H pylori infection was significantly higher in the cancer patients than that in the healthy control (68.6% vs 50.4%, P=0.003). Stratification analysis showed that COX-2 -899C carrier with H pylori infection had a higher risk for gastric cancer (OR=2.471, 95%CI: 1.076-5.675). CONCLUSION: COX-2 -899C genotype may increase the susceptibility to gastric cancer in high-incidence Hexi area of Gansu province in China. In addition, H pylori infection and COX-2-899C playa synergic role in gastric cancer pathogenesis. However, COX-2 codon 587G＞A has no relation with gastric cancer in this area.

Infection with cagA-positive H. pylori strains is associated with gastric carcinoma risk

Infection with cagA-positive H. pylori strains is associated with gastric carcinoma risk

Lack of association between Helicobacter pylori infection with dupA-positive strains and gastroduodenal diseases in Brazilian patients

Duodenal ulcer-promoting gene ( dupA) was recently described as a new putative Helicobacter pylori virulence marker associated with an increased risk for duodenal ulcer and reduced risk for gastric carcinoma in Japan and Korea. Since differences regarding the association among H. pylori markers and H. pylori-associated diseases have been demonstrated around the world, we evaluated the presence of the gene in 482 strains from Brazilian children (34 with duodenal ulcer and 97 with gastritis) and adults (126 with duodenal ulcer, 144 with gastritis and 81 with gastric carcinoma) by PCR using the described primers and an additional set of primers based on Brazilian strain sequences. The results were confirmed by sequencing. The presence of cagA was investigated by PCR and also included in the analysis. dupA was present in 445 (92.32%) and absent in 29 (6.02%) strains. All samples from children with and without duodenal ulcer were dupA-positive ( p=1.0). No association was observed among the strains from adults with gastritis (92.36%), duodenal ulcer (87.30%, p=0.30) and gastric carcinoma (87.65%, p=0.31). Conversely, cagA-positve status remained independently associated with duodenal ulcer (children: odds ratios (OR)=5.58, 95% confidence intervals (CI)=1.67–18.50; adults: OR=3.33, 95% CI=2.14–5.19) and gastric carcinoma (OR=6.58, 95% CI=3.51–12.30) in multivariate analyses. The presence of dupA was significantly higher in strains from children than in those from adults ( p=0.01). In conclusion, dupA is highly frequent and not associated with H. pylori-associated diseases in both Brazilian adults and children, which points to regional differences in the distribution of the gene.

PTENpolymorphisms and the risk of esophageal carcinoma and gastric cardiac carcinoma in a high incidence region of China

PTEN, as a tumor suppressor gene, plays an important role in regulating cell growth, proliferation, and apoptosis. Two common polymorphisms, -9C/G and IVS4 (-/+), may alter susceptibility to the disease. To test the hypothesis that the genetic variations of PTEN play a role in the etiology of esophageal squamous cell carcinoma (ESCC) and gastric cardiac adenocarcinoma (GCA), a population-based case-control study was conducted in 350 ESCC patients, 257 GCA patients, and 634 healthy controls from a high-incidence region of Hebei province, China. The PTEN polymorphisms were genotyped by polymerase chain reaction-restriction fragment length polymorphism analysis (PCR-RFLP). The results showed that the family history of upper gastrointestinal cancer (UGIC) significantly increased the risk of developing ESCC and GCA (the age, gender and smoking status adjusted OR = 1.73 and 1.67; 95% CI = 1.29-2.32 and 1.28-2.19, respectively). The overall distribution of the PTEN -9C/G genotype was not significantly different between cancer patients and controls. Compared with the PTEN IVS4-/- genotype, the IVS4+/+ genotype significantly decreased the risk of ESCC and GCA development, the adjusted OR was 0.64 (95% CI = 0.44-0.94) and 0.63 (95% CI = 0.41-0.98), respectively. Stratification analysis by gender, age, smoking status and family history of UGIC showed that the PTEN IVS4-/+ genotype only reduced the risk of ESCC (adjusted OR = 0.55, 95%CI = 0.34-0.90) among subjects with family history of UGIC. While the IVS4+/+ genotype decreased the susceptibility to both ESCC and GCA (adjusted OR = 0.61 and 0.57, 95% CI = 0.37-0.98 and 0.34-0.98, respectively) among male subjects, the IVS4+/+ genotype only decreased the risk of ESCC development among subjects younger than 55 years (adjusted OR = 0.43, 95% CI = 0.21-0.85). In addition, the haplotype analysis found that the -9C/IVS4- haplotype increased the risk of developing ESCC and GCA (OR = 1.31 and 1.24, 95% CI = 1.08-1.58 and 1.001-1.53). Our results suggested that the PTEN IVS4+/+ homozygote may play a protective role in the development of ESCC and GCA, while the haplotype -9C/IVS4- might be the risk factor of the development of ESCC and GCA in the high incidence region population of Hebei province, China.

Application of Microarray-Based Method for Methylenetetrahydrofolate Reductase (MTHFR) Polymorphisms in the Risk of Gastric Carcinoma in East China Population

The microarrays were fabricated to explore the relationship between methylenetetrahydrofolate reductase (MTHFR) polymorphisms (C677T and A1298C) and risk of gastric carcinoma in Chinese population. The genomic DNA was isolated from 170 patients with gastric carcinoma and 140 age- and sex-matched control subjects. The frequencies of C677T genotype were: CC (47.9%), CT (40%), CT (12.1%) in control group and CC (35.9%), CT (45.9%), TT (18.2%) in gastric carcinoma group, respectively. The individuals with 677CT + TT or 677TT genotypes had a 1.67-fold (95% CI: 1.06-2.64) or 2.67-fold (95% CI: 1.382-5.341) increased risk of developing gastric carcinoma compared with those carrying 677CC genotype. The genotype of MTHFR gene A1298C allele was not significantly different between the two groups. We found that a joint effect exits between the MTHFR C677T and A1298C polymorphism on the risk of gastric carcinoma. Our results show that the single nucleotide polymorphisms in the MTHFR gene are associated with the risk of gastric carcinoma in the east China population.

Interleukin-1β gene in esophageal, gastric and colorectal carcinomas

Interleukin (IL)-1 gene polymorphisms are associated with development of gastric atrophy and with increased risk of gastric carcinoma. A -31C to T base transition in the promoter region of this gene is involved in carcinogenic changes within the stomach, especially in Helicobacter pylori infected individuals. We examined association between IL-1 locus polymorphisms and risk of esophageal, gastric and colorectal carcinomas in Japanese patients with H. pylori infection. IL-1B and IL-1RN polymorphisms were analyzed in 136 controls, 75 patients with esophageal carcinoma, 186 patients with gastric carcinoma, 69 patients with colorectal carcinoma, and 18 patients with ulcerative colitis (UC). For IL-1B-511 and -31 polymorphisms were determined by fluorescence-based polymerase chain reaction single-strand conformation polymorphism analysis. For IL-1 receptor antagonist gene (IL-1RN), penta-allelic variable number of tandem repeats (VNTR) was determined by PCR-standard agarose gel electrophoresis. For gastric carcinoma, IL-1B-511 heterozygotes (OR, 0.48; 95% CI, 0.3-0.9; p=0.0115) and T carriers (OR, 0.52; 95% CI, 0.3-1.0; p=0.0185) had a significantly reduced risk of carcinoma. For colorectal carcinoma, IL-1B-511 heterozygotes (OR, 0.34; 95% CI, 0.2-0.7; p=0.0028) and T carriers (OR, 0.43; 95% CI, 0.2-0.9; p=0.0015) had a significantly low risk of carcinoma. No significant difference was observed in the frequencies of IL-1B-31C/T and IL-1RN genotypes between controls and the esophageal carcinoma patients. Our results shows that IL-1B-511C/T and T carrier state may indicate less risk for gastric and colorectal carcinoma in the Japanese population.

Laparoscopic Gastric Bypass with Subtotal Gastrectomy for a Super-Obese Patient with Biermer Anemia

Laparoscopic Roux-en-Y gastric bypass (RYGBP) is a common procedure for morbid obesity. After RYGBP, the bypassed stomach is unavailable for follow-up. Biermer anemia is an autoimmune atrophic gastritis inducing vitamin B12 deficiency and it is a risk factor for gastric carcinoma. A 41-year-old woman with a long history of morbid obesity presented with a BMI of 56 kg/m2. She had anemia (Hb 9.9 g/dL), and atrophic gastritis was found endoscopically. We performed a laparoscopic RYGBP with subtotal gastrectomy, to avoid the risk of gastric carcinoma in the bypassed stomach. The patient was discharged 9 days after the operation without complication. At 18 months follow-up, her BMI was 39 kg/m2 (50% excess weight loss). Laparoscopic RYGBP with subtotal gastrectomy is a safe treatment for morbid obesity, which should be considered for patients with a risk factor for gastric carcinoma.

Rugal hyperplastic gastritis increases the risk of gastric carcinoma, especially diffuse and p53-independent subtypes

Infection with Helicobacter pylori has been linked to chronic gastritis with atrophy or hyperrugosity. The development of noncardia gastric carcinoma, especially the intestinal type in Lauren's classification, has been associated with severe atrophic gastritis and p53 mutations. The objective of this study was to determine the association between hyperrugosity and gastric carcinogenesis, including p53 mutations. Barium meal roentgenograms were performed in 395 control participants and 132 gastric carcinoma patients. The fold width was measured at the greater curvature of the middle portion of the gastric body. Serum pepsinogens I and II were determined along with gastrin levels. Complete coding sequences and splice junctions for exons 5-8 of p53 gene were screened for mutations by polymerase chain reaction-based single-strand conformational polymorphism analysis. Rugal hyperplastic gastritis (gastric body fold width>or=5 mm) increased the risk of gastric carcinoma [odds ratio, 2.60; 95% confidence interval, 1.69-4.01] as compared with the control group, especially diffuse-type gastric carcinoma (odds ratio, 4.13; 95% confidence interval, 2.36-7.24). The p53 mutational rate was significantly lower in gastric carcinoma patients with rugal hyperplastic gastritis. In intestinal-type gastric carcinoma with hyperrugosity, the incidence of p53 gene mutations decreased, but no association was found in diffuse-type gastric carcinoma between p53 mutations and rugal hyperplastic gastritis. Rugal hyperplastic gastritis was associated with an elevated risk of gastric carcinoma, especially diffuse-type, and a lower frequency of p53 mutations.

Identification and Functional Characterization of JWA Polymorphisms and their Association with Risk of Gastric Cancer and Esophageal Squamous Cell Carcinoma in a Chinese Population

Recently, a novel single nucleotide polymorphism (SNP) in the promoter of the JWA gene (−76G → C) was identified that may alter the transcription activity and thus play a role in increased risk of bladder cancer. In this study, a screen for more novel variants in the JWA exons was undertaken by using polymerase chain reaction–single-strand conformation polymorphism (PCR-SSCP) followed by a PCR-restriction fragment length polymorphism (PCR-RFLP) method and evaluating the functions of newl identified JWA −76G → C using the reporter gene assay. In addition to the −76G → C polymorphism, another novel SNP (723T → G) in exon 3 of JWA was identified. In a case-control study of these two SNPs in 413 gastric cancer and 250 esophageal squamous-cell carcinoma (ESCC) patients and 814 cancer-free controls in a Chinese population, data showed that both SNPs were associated with enhanced risk of these cancers. The reporter gene assay showed that the −76C variant allele lost its response to benzo[a]pyrene (BaP) exposure, compared to the −76G allele. In addition, the JWA −76C allele was found to be associated with increased gastric and esophageal cancer risks in this study population. Further studies are needed to substantiate the biological significance and related mechanisms underlying the associations.

Role ofCD14Promoter Polymorphisms inHelicobacter pyloriInfection–Related Gastric Carcinoma

Genetic variation in CD14 may affect CD14 expression and susceptibility to Helicobacter pylori infection-related cancers. This study examined functional single nucleotide polymorphisms (SNP) in the CD14 promoter and their associations with risk of developing gastric carcinoma in relation to H. pylori infection. Thirty individual DNAs were sequenced to identify variants, and the function of the variants was examined by reporter gene assays. Genotypes and haplotypes were analyzed in 470 patients and 470 controls, and odds ratios (OR) and 95% confidence intervals (95% CI) were estimated by logistic regression. Serologic H. pylori antibody and soluble CD14 (sCD14) levels were measured by ELISA. Two SNPs (-651C>T and -260C>T) were identified, of which the -260CT and -260TT genotypes were associated with elevated risk of gastric carcinoma (OR, 1.77; 95% CI, 1.09-2.85 and OR, 1.95; 95% CI, 1.20-3.16, respectively). Haplotype analysis suggested a synergistic effect of the two SNPs (OR for the T(-651)-T(-260) haplotype, 3.39 versus OR for the C(-651)-T(-260) haplotype, 1.45; P = 0.02), which is consistent with reporter gene assays. A multiplicative joint effect between H. pylori infection and -260C>T polymorphism was observed (OR for the presence of both -260TT genotype and H. pylori infection, 4.03; 95% CI, 1.80-9.04). Patients had significantly higher sCD14 than controls (1,866 +/- 2,535 ng/mL versus 1,343 +/- 2,119 ng/mL; P < 0.001), and this difference was associated with the CD14 -260 polymorphism and H. pylori infection. Functional polymorphism in CD14 is associated with greater risk of H. pylori-related gastric carcinoma, which might be mediated by elevated sCD14.

Familial risk for gastric carcinoma: an updated study from Sweden

Reliable data on familial risks are important for clinical counselling and cancer genetics. However, the estimates of familial risk of gastric cancer vary widely. We examined the risk of familial gastric cancer using the updated Swedish Family-Cancer Database with 5358 patients among offspring and 36 486 patients among parents. There were 133 families with one parent and one offspring diagnosed with gastric cancer, and 20 families with two affected offspring. Familial standardised incidence ratios (SIRs) were 1.63 and 2.93 when parents and siblings presented with gastric cancer, respectively. The high sibling risk was owing to cancer in the corpus (SIR 7.28). The SIR for cardia cancer was 1.54 when parents were diagnosed with any gastric cancer. Cardia cancer associated with oesophageal cancer, particularly with oesophageal adenocarcinoma. Among specific histologies, signet ring cancer showed an increase. A few associations were noted for discordant sites, including the urinary bladder and the endometrium. H. pylori infection, although not measured in the present study, is probably an important risk factor for the high sibling risk of corpus cancer. Familial clustering of cardia cancer is independent of H. pylori infection, and may have a genetic basis. The familial association of cardia cancer with oesophageal adenocarcinoma may provide aetiological clues.

Inducible nitric oxide synthase gene promoter polymorphism is associated with increased gastric mRNA expression of inducible nitric oxide synthase and increased risk of gastric carcinoma

Stimulation of inducible nitric oxide synthase gene expression by Helicobacter pylori, with subsequent overproduction of nitric oxide, has been implicated in gastric carcinogenesis. We investigated whether inducible nitric oxide synthase promoter gene polymorphisms are associated with (a) inducible nitric oxide synthase mRNA expression in the gastric mucosa, and (b) the risk of gastric carcinoma. The relationship between gastric inducible nitric oxide synthase mRNA expression and inducible nitric oxide synthase promoter polymorphisms (CCTTT repeat polymorphism and -2445 C-->G SNP) was examined in 74 H. pylori-infected patients with gastric cancer, peptic ulcer, or functional dyspepsia. In a case-control study the prevalence of the polymorphisms was examined in H. pylori-infected gastric carcinomas (n=77) and noncancerous controls (n=154). Inducible nitric oxide synthase mRNA levels were significantly higher in long CCTTT repeat (either allele>11) carriers than in short ones (P=0.015). Multivariate regression analysis showed that inducible nitric oxide synthase mRNA expression was significantly linked to long CCTTT repeat and gastric cancer (P=0.026), but not to -2445 C-->G SNP and other parameters. The case-control study showed that long CCTTT repeat carriers had an increased risk of gastric cancer with an odds ratio of 2.0 (P=0.021). -2445 C-->G SNP was not associated with the risk. Helicobacter pylori induces higher inducible nitric oxide synthase mRNA expression in carriers of long CCTTT repeats of inducible nitric oxide synthase promoter, and this polymorphism is associated with an increased risk of gastric carcinoma.

Helicobacter pylori, chronic atrophic gastritis, inactive aldehyde dehydrogenase‐2, macrocytosis and multiple upper aerodigestive tract cancers and the risk for gastric cancer in alcoholic Japanese men

Gastric carcinoma occurs at a high rate in alcoholic Japanese men. Inactive heterozygous aldehyde dehydrogenase-2 (ALDH2*1/2*2) and macrocytosis (mean corpuscular volume [MCV] > or = 106 fl) enhance the risk for esophageal carcinoma, which frequently occurs with gastric carcinoma in this population. Whether alcoholism affects Helicobacter pylori-induced chronic atrophic gastritis (CAG) is unknown. This study of Japanese alcoholic men with (n = 45) and without (n = 281) gastric carcinoma included assessment of H. pylori IgG antibody, serum pepsinogen-confirmed CAG, MCV, and ALDH2 genotype. The gastric carcinoma cases had a significantly higher age-adjusted prevalence of H. pylori-positivity (78%vs 57%), CAG (78%vs 42%), ALDH2*1/2*2 (36%vs 14%), MCV > or =106 fl (38%vs 20%), and concurrent esophageal/oropharyngolaryngeal carcinoma (18%vs 5%) than controls. Among gastric cancer-free controls, the prevalence of CAG was higher than generally reported in Japan, regardless of H. pylori status (H. pylori-positive, 56%vs 35-36% for Japanese general population; H. pylori-negative, 8%vs 1-3%). Alcoholism may accelerate the progression of CAG. Each of these factors increased the risk of gastric carcinoma (OR(s) = 3.7 for H. pylori-positive, 2.7 for non-severe CAG, 8.7 for severe CAG, 3.5 for ALDH2*1/2*2, 2.5 for MCV > or =106 fl, and 3.7 for concurrent carcinoma). A multivariate analysis showed that CAG and ALDH2*1/2*2 were independently related to the risk of gastric carcinoma. Combinations of CAG and ALDH2*1/2*2 showed greater risks of gastric carcinoma (OR(s) = 4.0 for non-severe CAG alone, 17.6 for severe CAG alone, 9.7 for ALDH2*1/2*2 alone, 17.1 for non-severe CAG plus ALDH2*1/2*2, and 39.2 for severe CAG plus ALDH2*1/2*2). Combining blood tests for H. pylori, CAG, MCV and ALDH2 genotype could offer a new means of predicting risk of gastric carcinoma in Japanese alcoholic men.

A Functional Polymorphism of Toll-Like Receptor 4 Gene Increases Risk of Gastric Carcinoma and Its Precursors

A Functional Polymorphism of Toll-Like Receptor 4 Gene Increases Risk of Gastric Carcinoma and Its Precursors

A Functional Polymorphism of Toll-Like Receptor 4 Gene Increases Risk of Gastric Carcinoma and Its Precursors

TLR4 is a cell-surface signaling receptor involved in the recognition and host response to Helicobacter pylori. The TLR4+896A>G polymorphism linked with impaired reactivity to bacterial lipopolysaccharide may play a role in gastric carcinogenesis. We assessed associations with premalignant gastric changes in 149 relatives of gastric cancer patients, including 45 with hypochlorhydria and gastric atrophy. We also genotyped 2 independent Caucasian population-based case-control studies of upper gastrointestinal tract cancer, initially in 312 noncardia gastric carcinoma cases and 419 controls and then in 184 noncardia gastric carcinomas, 123 cardia carcinomas, 159 esophageal cancers, and 211 frequency-matched controls. Odds ratios were computed from logistic models and adjusted for potential confounding factors. TLR4+896G carriers had an 11-fold (95% confidence interval [CI], 2.5-48) increased odds ratio (OR) for hypochlorhydria; the polymorphism was unassociated with gastric acid output in the absence of H pylori infection. Carriers also had significantly more severe gastric atrophy and inflammation. Seventeen percent of gastric carcinoma patients in the initial study and 15% of the noncardia gastric carcinoma patients in the replication study had 1 or 2 TLR4 variant alleles vs 8% of both control populations (combined OR = 2.3; 95% CI = 1.6-3.4). In contrast, prevalence of TLR4+896G was not significantly increased in esophageal squamous cell (2%, OR = 0.2) or adenocarcinoma (9%, OR = 1.4) or gastric cardia carcinoma (11%, OR = 1.4). Our data suggest that the TLR4+896A>G polymorphism is a risk factor for noncardia gastric carcinoma and its precursors. The findings underscore the role of the host innate immune response in outcome of H pylori infection.

The Helicobacter pylori CagA protein disrupts matrix adhesion of gastric epithelial cells by dephosphorylation of vinculin

Helicobacter pylori colonizes the human stomach, contributing to or causing several diseases. Translocation of the CagA bacterial protein into gastric epithelial cells has been linked to an increased risk of peptic ulcer disease and gastric carcinoma. Upon translocation, CagA is tyrosine phosphorylated by Src family kinases (SFKs), which themselves become inactivated via a negative feedback loop. Here, we show that tyrosine-phosphorylated CagA disrupts adhesion of AGS cells to the extracellular matrix. Owing to the inactivation of c-Src via CagA interaction, vinculin is dephosphorylated at tyrosine residues, 100 and 1065, by corresponding phosphatases. Vinculin dephosphorylation disturbs the interaction and recruitment of the actin-related protein 2/3 (Arp2/3) complex by p34Arc, resulting in a reduction of focal adhesion complexes. These defects can be mimicked by downregulating vinculin using RNA interference in non-infected cells. Tyrosine dephosphorylation of vinculin results in severe cellular deficiencies in cell-matrix adhesion, cell spreading and wound repair. We hypothesize that CagA-mediated inactivation of vinculin is a key step in the mechanism by which H. pylori induces damage to the gastric epithelium and represents an important step in disease development.

Helicobacter pylori Induces Gastric Epithelial Cell Invasion in a c-Met and Type IV Secretion System-dependent Manner

Helicobacter pylori interacts with gastric epithelial cells, activating signaling pathways important for carcinogenesis. In this study we examined the role of H. pylori on cell invasion and the molecular mechanisms underlying this process. The relevance of H. pylori cag pathogenicity island-encoded type IV secretion system (T4SS), CagA, and VacA for cell invasion was also investigated. We found that H. pylori induces AGS cell invasion in collagen type I and in Matrigel invasion assays. H. pylori-induced cell invasion requires the direct contact between bacteria and cancer cells. H. pylori-mediated cell invasion was dependent on the activation of the c-Met receptor and on increased MMP-2 and MMP-9 activity. The abrogation of the c-Met receptor using the specific NK4 inhibitor or the silencing of c-Met expression with small interference RNA suppressed both cell invasion and MMP activity. Studies with different H. pylori strains revealed that cell invasion, c-Met tyrosine phosphorylation, and increased MMP-2 and MMP-9 activity were all dependent on the presence of a functional bacterial T4SS, but not on VacA cytotoxicity. Our findings demonstrate that H. pylori strains with a functional T4SS stimulate gastric epithelial cell invasion through a c-Met-dependent signaling pathway that comprises an increase in MMP-2 and MMP-9 activity.

MDM2 Promoter Polymorphism Is Associated With Both an Increased Susceptibility to Gastric Carcinoma and Poor Prognosis

Recently, a single-nucleotide polymorphism in the MDM2 promoter (SNP309) has been found to lower the age of onset of tumors and increase the occurrence of multiple primary tumors in Li-Fraumeni syndrome, and accelerate the development of sporadic adult soft tissue sarcoma. The aim of this study was to determine whether SNP309 is associated with susceptibility to gastric carcinoma and its prognosis. In a case-control study including 438 controls and 410 patients with sporadic gastric carcinoma, MDM2 SNP309 was genotyped. Serum pepsinogens (PGs) I and II were measured in 438 control subjects and 253 cases selected from 410 patients. Tumor tissue was immunostained with p53 and examined for mutations in exons 5 to 8 of p53 using polymerase chain reaction-based single strand conformational polymorphism analysis and direct sequencing. The risk of overall gastric carcinoma for SNP309 (G/G) was significantly increased when compared with T carriers (P = .039), especially carcinomas with extragastric tumors (P = .005), carcinoma with severe atrophic gastritis positive for PG assay (PG I level < 70 ng/mL and PG I/II < 3.0; P = .005), antral carcinoma (P = .020), intestinal-type carcinoma (P = .023), p53-immunopositive carcinoma (P = .007), and carcinoma with p53 mutations (P = .007). No significant difference in age at diagnosis was observed among genotypes. SNP309 (G/G) was an independent marker of poor overall survival in advanced carcinoma (hazard ratio, 3.16; 95% CI, 1.22 to 8.20; P = .018). This study provides evidence supporting the association of SNP309 with gastric carcinogenesis via p53 tumor suppressor pathway, extragastric tumorigenesis, and poor prognosis.

Interleukin‐8 gene polymorphism associated with susceptibility to non‐cardia gastric carcinoma with microsatellite instability

Gastric carcinoma (GC) with microsatellite instability (MSI) exhibits clinicopathological characteristics distinct from microsatellite-stable (MSS) GC. Both MSI and MSS carcinomas are mostly associated with chronic gastritis infected by Helicobacter pylori (Hp). The relationship between Hp-induced inflammation and the mutator pathway of MSI remains unclear. Recently, cytokine polymorphisms have been reported to affect the development of non-cardia GC. The objective of this study was to elucidate the relationship between cytokine polymorphisms and MSI phenotypes. In a case-control study including 482 controls and 181 patients with GC, interleukin (IL)-8 -251, IL-1B-511, IL-1RN, and tumor necrosis factor-A (TNFA) -857 polymorphisms were genotyped. The presence of MSI and mutations in exons 5 to 8 of the p53 gene were examined in GC cases. All clinicopathological data were collected from individual records. High and low frequency of MSI (MSI-H and MSI-L) and MSS were detected in 16 (8.8%), 14 (7.7%) and 151 (83.4%) GC cases, respectively. We found that IL-8 -251 T/T genotype was significantly associated with increased risk of MSI-H GC compared to MSI-L/MSS GC and controls. We found no association between other cytokine polymorphisms and MSI-H GC. The percentage of smokers and the frequency of p53 mutations were significantly lower in MSI-H than MSI-L/MSS GC. We found significant associations of MSI-H with synchronous or metachronous multiple occurrence, antral location and intestinal type. Our study shows that MSI-H GC is associated with IL-8-251 T/T (low expression genotype) and is inversely correlated with cigarette smoking.