Helicobacter pylori infection in relation to gastric cancer progression

Association of Helicobacter pylori infection with metabolic parameters and dietary habits among medical undergraduate students in southeastern of Iran

Background:

To date, there is still inconclusive evidence on the extra-gastric manifestations of Helicobacter pylori (H.pylori) infection. This study aimed to determine whether there is an association between H.pylori infection with metabolic syndrome and dietary habits among medical undergraduate students in south-eastern of Iran, Zahedan.

Materials and Methods:

This cross-sectional study was done among 363 undergraduate students in Zahedan University of Medical Sciences during spring 2014. All subjects completed a questionnaire including demographic factors and dietary habits. Serum H. pylori-specific IgG antibodies, total cholesterol (TC), triglycerides (TG), high-density lipoprotein-cholesterol (HDL-C), low-density lipoprotein-cholesterol (LDL-C), and fasting blood sugar (FBS) levels were measured after an overnight fast.

Results:

The seroprevalence of H. pylori infection was 45.7%. H. pylori-positive subjects had lower mean levels of TC and TG and higher levels of HDL-C compared to H. pylori-negative subjects. In addition, lower levels of LDL-C (P = 0.044) and FBS (P = 0.05) were observed among subjects with positive H pylori infection. Only rare consumption of raw vegetables (odds ratio [OR] =3.74, 95% confidence interval [CI] =1.37–5.24) as well as higher levels of FBS (OR = 1.031, 95% CI = 1.001–1.99) were significantly associated with higher odds of H. pylori infection in both the univariate and multiple logistic regression analysis.

Conclusion:

In a small population of young students in southeastern of Iran, H. pylori infection was associated with low consumption of raw vegetables and higher serum blood glucose.

Host pathogen interactions in Helicobacter pylori related gastric cancer

Helicobacter pylori (H. pylori), discovered in 1982, is a microaerophilic, spiral-shaped gram-negative bacterium that is able to colonize the human stomach. Nearly half of the world's population is infected by this pathogen. Its ability to induce gastritis, peptic ulcers, gastric cancer and mucosa-associated lymphoid tissue lymphoma has been confirmed. The susceptibility of an individual to these clinical outcomes is multifactorial and depends on H. pylori virulence, environmental factors, the genetic susceptibility of the host and the reactivity of the host immune system. Despite the host immune response, H. pylori infection can be difficult to eradicate. H. pylori is categorized as a group I carcinogen since this bacterium is responsible for the highest rate of cancer-related deaths worldwide. Early detection of cancer can be lifesaving. The 5-year survival rate for gastric cancer patients diagnosed in the early stages is nearly 90%. Gastric cancer is asymptomatic in the early stages but always progresses over time and begins to cause symptoms when untreated. In 97% of stomach cancer cases, cancer cells metastasize to other organs. H. pylori infection is responsible for nearly 60% of the intestinal-type gastric cancer cases but also influences the development of diffuse gastric cancer. The host genetic susceptibility depends on polymorphisms of genes involved in H. pylori-related inflammation and the cytokine response of gastric epithelial and immune cells. H. pylori strains differ in their ability to induce a deleterious inflammatory response. H. pylori-driven cytokines accelerate the inflammatory response and promote malignancy. Chronic H. pylori infection induces genetic instability in gastric epithelial cells and affects the DNA damage repair systems. Therefore, H. pylori infection should always be considered a pro-cancerous factor.

Gene polymorphisms of pathogenic Helicobacter pylori in patients with different types of gastrointestinal diseases

Helicobacter pylori (H. pylori) is a kind of chronic infectious pathogen which can cause chronic gastritis, peptic ulcer, gastric cancer and other diseases. The genetic structure of the pathogenic genes of H. pylori varies largely, which contributes to the differences in virulence among various strains, and in clinical symptoms. Virulence genes of H. pylori can be categorized into three main classes: those related to adhesion and colonization, those related to gastric mucosal injury, and others. This review focuses on the relationship between genetic polymorphisms of the three classes of virulence genes of H. pylori and diseases. Most of the genetic polymorphisms of the main virulence factors of H. pylori are summarized in this paper.

Her2/neu Protein Expression and Oncogene Amplification in Gastric Carcinoma with Clinico-Pathological Correlation in Egyptian Patients

AIM

Amplification of the Her2/neu gene and overexpression of the Her2/neu protein in gastric carcinoma (GC) is a golden criterion for target therapy with trastuzumab (Herceptin). We aim to evaluate the immunohistochemical protein expression and amplification of the oncogene Her2/neu by FISH technique in the epithelial gastric carcinoma and to compare their association with different clinicopathologic parameters aiming at identifying positive cases that may benefit from targeted therapy.

MATERIALS AND METHODS

This study was done on eighty-five tumour tissue samples from patients with GC as well as thirty non-malignant lesions (Gastritis, intestinal metaplasia, adenoma with low-grade dysplasia, adenoma with high-grade dysplasia). All were immunohistochemically stained with Her2/neu antibody.

RESULTS

All equivocal and some selected GC cases were submitted for FISH technique to detect Her2/neu gene amplification. By immunohistochemistry twenty-three cases (27%) were defined as positive for Her2/neu gene amplification and/or protein overexpression. The levels of Her2/neu positive (3+), Her2/neu equivocal (2+) and Her2/neu negative (1+/0) were measurable in 14.2%, 32.9% and 52.9% of the samples, respectively. FISH showed that Her2/neu gene was amplified in 22 cases, 10 Her2/neu positive (3+), 11 (39.3%) Her2/neu equivocal (2+) and 1 Her2/neu negative (1+) cases with IHC staining those who can benefit from anti Her2/neu target therapy. Her2/neu was overexpressed positivity (3+) more in intestinal type and mixed carcinoma, and moderately differentiated tumours. None of gastritis, intestinal metaplasia or adenoma with low-grade dysplasia cases showed positivity for Her2/neu (3+). The Her2/neu positivity (3+) was associated with both adenocarcinoma cases and high-grade dysplasia (P = 0.002).

CONCLUSIONS

The results highlight the necessity of FISH test for further categorization when gastric cancer cases are equivocal (2+) by IHC to determine eligibility for the targeted therapy. Stepwise increase in the expression of Her2/neu was seen in low-grade dysplasia, high-grade dysplasia and carcinoma cases implying its role in cancer evolution. Overexpression of Her 2/neu in GC patients can be promising in selecting those who can get benefit from anti-Her2/neu target therapy.

Association of smoking, alcohol and NSAIDs use with expression of cag A and cag T genes of Helicobacter pylori in salivary samples of asymptomatic subjects

OBJECTIVE

To determine the association of smoking, alcohol and nonsteroidal anti-inflammatory drugs (NSAIDs) use with presence and virulence of Helicobacter pylori (H. pylori) infection in a representative sample of a random adult population of asymptomatic subjects.

METHODS

Non virulent 16S rRNA and virulent cag A and T genes from salivary samples of 854 asymptomatic subjects were determined using polymerase chain reaction. The presence and absence of virulent and non virulent infection was statistically compared with consumption of smoking, alcohol and NSAIDs.

RESULTS

The prevalence of infection in male and female subjects was found to be 69.25% and 66.90%, respectively. The prevalence of infection in the population of asymptomatic subjects with respect to consumption of alcohol was as follows: current (31.22%), former (52.20%) and never (43.58%). The prevalence of infection in the population of asymptomatic subjects with respect to smoking of cigarettes was as follows: current (88.80%), former (57.14%) and never (33.33%). The prevalence of infection in the subject population consuming NSAIDs and not consuming NSAIDs frequently was found to be 82.75% and 21.16%, respectively. Virulence in male and female subjects was found to be 60.00% and 50.00%, respectively. The presence of virulent infection in the population of asymptomatic subjects with respect to consumption of alcohol was as follows: current (28.57%), former (40.15%) and never (50.00%). The prevalence of virulent infection in the population of asymptomatic subjects with respect to smoking of cigarettes was as follows: current (79.32%), former (75.00%) and never (50.00%). The prevalence of virulent infection in the subject population consuming NSAIDs and not consuming NSAIDs frequently was found to be 88.23% and 66.66%, respectively.

CONCLUSIONS

It can be concluded that smoking and NSAIDs consumption are aggravating factors for virulence of H. pylori and alcohol can inhibit H. pylori infection in asymptomatic subjects.

Helicobacter pylori infection: New pathogenetic and clinical aspects

Helicobacter pylori (H. pylori) infects more than half of the world’s human population, but only 1% to 3% of infected people consequently develop gastric adenocarcinomas. The clinical outcome of the infection is determined by host genetic predisposition, bacterial virulence factors, and environmental factors. The association between H. pylori infection and chronic active gastritis, peptic ulcer disease, gastric cell carcinoma, and B cell mucosa-associated lymphoid tissue lymphoma has been well established. With the exception of unexplained iron deficiency anemia and idiopathic thrombocytopenic purpura, H. pylori infection has no proven role in extraintestinal diseases. On the other hand, there is data showing that H. pylori infection could be beneficial for some human diseases. The unpredictability of the long-term consequences of H. pylori infection and the economic challenge in eradicating it is why identification of high-risk individuals is crucial.

Association of the miR-146aC>G, miR-149T>C, and miR-196a2T>C polymorphisms with gastric cancer risk and survival in the Greek population

MicroRNAs (miRNAs) play an important role in regulating gene expression at the post-transcriptional level and are involved in numerous physiological processes. Accumulating evidence suggests that single-nucleotide polymorphisms (SNPs) in human miRNA genes may affect miRNA biogenesis pathway and influence the susceptibility to several diseases such as cancer. The aim of the study was to investigated whether three common miRNA polymorphisms [miR-146a C>G (rs2910164), miR-149 T>C (rs2292832), and miR-196a2 T>C (rs11614913)] are associated with the susceptibility and prognosis of gastric cancer (GC) in the Greek population. The three mRNA SNPs were identified in a case-control study (163 patients; 480 controls) by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. We found that the risk for GC was significantly higher for the carriers of miR-149 rs2292832CC (p = 0.009) and miR-196a2 rs11614913CC (p < 0.0001) genotypes, as well as for the carriers of the rs2910164/rs2292832/rs11614913 CCC and GTC haplotype (p < 0.0001 and p = 0.03, respectively). The rs2910164/rs2292832/rs11614913 CTT and CCT haplotypes seems to have a protective role against GC (p = 0.002 and p = 0.001, respectively). Our data demonstrate that specific miRNA SNPs are associated with GC susceptibility in the Greek population.

Epidemiology of gastric cancer in the gangetic areas of west bengal

There is marked geographical variation in the distribution and incidence of stomach cancer. We tried here to describe the pattern of relationships of age, sex, religion distribution, symptom profile, histological subtypes and Helicobacter pylori (H. pylori) infection with gastric cancer in Gangetic West Bengal. This study was done over a period of five years (2006–2010). The patients residing in the Gangetic areas of West Bengal presenting with upper gastrointestinal symptoms underwent UGI endoscopy. Among gastric cancer patients, demographic characteristics, symptomatology, macroscopic and histologic lesions and H. pylori status were analyzed. At confidence level 95%, “Z” and “P” value were calculated to find significance. Among 23851 patients underwent UGI endoscopy, 14106 were males, 9745 females, 17889 Hindus and 5962 Muslims. Among 462 gastric cancer patients, Male : Female 2.7 : 1, Hindus : Muslim 3 : 1, abdominal pain, indigestion, and weight-loss were commonest presentations. Antrum was the commonest site whereas ulceroproliferative type was commonest type. H. pylori positivity was 80.89% in adenocarcinoma with statistically significant relation with intestinal type. In future, our target will be to modify risk factors; it will need further demographic studies and analysis, so that we can detect it earliest.

E-Selectin S128R gene polymorphism in gastric cancer

BACKGROUND

E-selectin is an adhesion molecule expressed on activated endothelial cells. E-selectin plays an important role in the process of inflammation and is also involved in the mechanism of cancer metastasis regulating the adhesion of circulating cancer cells to the blood vessels. The aim of our study was to determine whether an association exists between its most common gene polymorphism, S128R, and gastric cancer (GC).


METHODS

We performed a case-control study of 88 GC cases and 480 controls to analyze the association between E-selectin S128R gene polymorphism and GC susceptibility. The genotyping analysis was done by PCR-restriction fragment length polymorphism method. 


RESULTS

The E-selectin S128R C allele, CA and CC genotypes were over-represented among the GC cases. No statistically significant association was observed between E-selectin S128R polymorphisms and tumor characteristics. However, carrying the C allele was associated with poor survival. 


CONCLUSIONS

The E-selectin S128R C allele may confer an increased susceptibility to gastric cancer development and correlate with a poor prognosis.

Effects of stromal cell-derived factor-1 and survivin gene polymorphisms on gastric cancer risk

Stromal-cell derived factor-1 (SDF-1), a CXC chemokine, is important for growth, angiogenesis and metastasis of tumor cells. The SDF1-3'A polymorphism has been investigated in various types of cancer; however, no information is currently available on its role in gastric cancer. Survivin is a member of the inhibitor of apoptosis family of proteins and has a genetic polymorphism (-31G/C) located in the CDE/CHR repressor element of its promoter. In this study, 88 gastric cancer patients and 480 normal healthy control subjects were investigated for the genotype and allelic SDF1-3'A and survivin -31G/C frequencies using polymerase chain reaction‑restriction fragment length polymorphism. The SDF1-3'A genotype frequencies for GG, GA and AA were 44.32, 48.86 and 6.92% in patients and 42.71, 47.71 and 9.58% in healthy subjects, respectively. GA+AA genotype frequency and A allele distribution were not identified as significantly different between gastric cancer cases and controls. The survivin frequencies for GG, GC and CC were 20.45, 50 and 29.54% in patients and 33.96, 45 and 21.04% in healthy subjects, respectively. The C carriers (GC+CC genotype) and the C allele were over-represented among the gastric cancer cases (P=0.013 and P=0.0083, respectively). Overall, no statistically significant association was identified for SDF-1 and survivin gene examined alleles and genotypes and any parameter investigated, (e.g., stage, differentiation status and survival). The survivin promoter -31G/C polymorphism may confer an increased susceptibility to gastric cancer, while the SDF1-3'A polymorphism may not be a candidate genetic variant to select individuals at higher risk of developing gastric cancer.

Stepwise cumulation of RUNX3 methylation mediated by Helicobacter pylori infection contributes to gastric carcinoma progression

BACKGROUND

Helicobacter pylori has been recognized as a definite carcinogen for gastric cancer (GC); however, the pathogenesis of H. pylori infection remains unclear. Runt-related transcription factor 3 (RUNX3) is a candidate tumor suppressor gene whose deficiency is causally related to GC. However, in H. pylori infection-associated GC, the role of RUNX3 has not been studied.

METHODS

The authors used real-time methylation-specific polymerase chain reaction analysis to determine methylation status of the RUNX3 promoter in a spectrum of gastric lesions, including 220 samples of chronic atrophic gastritis, 196 samples of intestinal metaplasia, 134 samples of gastric adenoma, 102 samples of dysplasia, and 202 samples of GC with paired noncancerous mucosa tissues and corresponding blood specimens. The association of abnormal methylation with precancerous gastric lesions was evaluated along with the association between RUNX3 methylation and H. pylori infection, and the concordance of methylation levels was investigated between serum and tissues.

RESULTS

The results indicated that increasing RUNX3 promoter methylation was correlated with distinct stages of GC progression. GC tissues had the highest methylation proportion (75.2%) compared with precancerous gastric lesions, including chronic atrophic gastritis (15.9%), intestinal metaplasia (36.7%), gastric adenoma (41.8%), and dysplasia (54.9%). H. pylori infection, a major risk factor for GC, contributed to the inactivation of RUNX3 in gastric epithelial cells through promoter hypermethylation. The levels of RUNX3 methylation in serum were in significant concordance with the methylation levels observed in GC tissues (P = .887).

CONCLUSIONS

The current findings supported RUNX3 methylation as a risk factors for the carcinogenesis of chronic atrophic gastritis with H. pylori infection and indicated that circulating RUNX3 methylation is a valuable biomarker for the detection of early GC.