Increased expression of cyclooxygenase-2 in first-degree relatives of gastric cancer patients

-765 g>c polymorphism of the cox-2 gene and gastric cancer risk in Brazilian population

CONTEXT

Genomic alterations play important roles in gastric cancer carcinogenesis. Cyclooxygenases (COX) are important enzymes in the maintenance of mucosal integrity and in pathological processes, mainly in inflammation and cancer. The -765G>C COX-2 polymorphism has been implicated in gastric cancer risk.

OBJECTIVES

To evaluate the COX-2 gene polymorphism as a predictor of gastric cancer risk.

METHODS

One hundred gastric cancer patients and 150 controls were enrolled from a Brazilian centre. Personal data regarding related risk factors, including alcohol consumption and smoking behavior, were collected via questionnaire. DNA was extracted from peripheral blood and the genotypes were analyzed using PCR-restriction fragment length polymorphism.

RESULTS

G/G, G/C and C/C genotypes frequencies was 42.7%, 50% and 7.3%, respectively in controls and 59.0%, 34.0% and 7.0% in gastric cancer. The frequency of the genotypes differed between the groups (P = 0.033). A higher risk of gastric cancer was associated with COX-2 -765G/G genotype (P = 0.048; OR:1.98, 95% CI = 1.01-3.90). Alcohol consumption and smoking in patients with -765G/G genotype also increased the risk of gastric cancer.

CONCLUSIONS

The -765G/G genotype and the -765G allele had been associated with an increased risk for gastric cancer. The presence of smoking and alcohol consumption increased the risk for gastric cancer in subjects with -765G/G genotype compared with the control group. Polymorphism of COX-2 gene and gastric cancer risk.

Gastric precancerous lesions in first degree relatives of patients with known gastric cancer: a cross-sectional prospective study in Guilan Province, north of Iran

BACKGROUND AND OBJECTIVES

In patients with gastric cancer, the most frequently reported family history of cancer also involves the stomach. The aim of this study was to assess the presence of gastric precancerous lesions in first-degree relatives of patients with gastric cancer and to compare the obtained results with those of individuals with no such family history.

METHODS

Between 2007 and 2009, 503 consecutive persons more than 30 years old were enrolled in the study covering siblings, parents or children of patients with confirmed adenocarcinoma of stomach. The control group was made up of 592 patients who were synchronously undergoing upper gastrointestinal endoscopy for evaluation of dyspepsia without gastric cancer or any family history. All subjects were endoscopically examined.

RESULTS

The overall prevalence of Helicobacter pylori was 77.7% in the cancer relatives and in 75.7% in the control group. Chronic gastritis was found in 90.4% vs. 81.1% (P<0.001). Regarding histological findings, 37(7.4%) of the study group had atrophy vs. 12(1.7%) in the control group (P<0.001), while no difference was observed for intestinal metaplasia (20.3%vs. 21.6%, P=0.58). Dysplasia were shown in 4% of cancer relatives but only 0.4% of the control group (P<0.001). There was no gender specificity.

CONCLUSIONS

Findings of our study point to great importance of screening in relatives of gastric cancer patients in Iran.

Gene expression in response to ionizing radiation and family history of gastric cancer

Genes and molecular pathways involved in familial clustering of gastric cancer have not yet been identified. The purpose of the present study was to investigate gene expression changes in response to a cellular stress, and its link with a positive family history for this neoplasia. To this aim leukocytes of healthy first-degree relatives of gastric cancer patients and controls were challenged in vitro with ionizing radiation and gene expression evaluated 4 h later on microarrays with 1,800 cancer-related genes. Eight genes, mainly involved in signal transduction and cell cycle regulation, were differentially expressed in healthy relatives of gastric cancer cases. Functional class scoring by Gene Ontology classification highlighted two G-protein related pathways, implicated in the proliferation of neoplastic tissue, which were differentially expressed in healthy subjects with positive family history of gastric cancer. The relative expression of 84 genes related to these pathways was examined using the SYBR green-based quantitative real-time PCR. The results confirmed the indication of an involvement of G-protein coupled receptor pathways in GC familiarity provided by microarray analysis. This study indicates a possible association between familiarity for gastric cancer and altered transcriptional response to ionizing radiation.

Polymorphism of -765G > C COX-2 is a risk factor for gastric adenocarcinoma and peptic ulcer disease in addition to H pylori infection: A study from northern India

AIM: To investigate -765G > C COX-2 polymorphism and H pylori infection in patients with gastric adenocarcinoma, peptic ulcer disease (PUD) and non-ulcer dyspepsia (NUD).

METHODS: We enrolled 348 adult patients (62 gastric adenocarcinoma, 45 PUD and 241 NUD) undergoing upper gastrointestinal endoscopy at two referral centers between September, 2002 and May, 2007. H pylori infection was diagnosed when any of the four tests (RUT, culture, histopathology and PCR) were positive. Genotyping for -765G > C polymorphism of COX-2 was performed by PCR-RFLP analysis.

RESULTS: Frequency of C carrier had significant association with gastric adenocarcinoma as compared to NUD [77.4% vs 29%, P < 0.001, odds ratio (OR) 8.20; 95% confidence interval (95% CI), 4.08-16.47] and PUD (77.4% vs 31.1%, P < 0.001; OR 8.04; 95% CI, 3.25-19.90). Risk of gastric adenocarcinoma was significantly higher in patients having C carrier with (OR 7.83; 95% CI 3.09-19.85) and without H pylori infection (OR 7.06; 95% CI, 2.61-19.09). Patients with C carrier and H pylori infection had significant risk for the development of PUD (P < 0.001; OR 5.65; 95% CI, 2.07-15.34).

CONCLUSION: -765G > C COX-2 polymorphism with or without H pylori could be a marker for genetic susceptibility to gastric adenocarcinoma. COX-2 polymorphism in presence of H pylori infection might be useful in predicting the risk of PUD.

Dietary supplementation with carbonate increases expression of ornithine decarboxylase and proliferation in gastric mucosa in a rat model of gastric cancer

Dietary factors play essential roles in gastric carcinogenesis. We recently found that dietary supplementation with NaHCO(3) significantly increased the development of gastric cancer in a rat gastric stump model. Here, we analysed nontransformed gastric mucosa for expression of the cancer-related proteins cyclooxygenase-2 (COX-2) and ornithine decarboxylase (ODC), and we examined the relationship between expression levels of those proteins and mucosal proliferation. Research has shown that COX-2 is upregulated in gastric mucosal inflammation and is strongly associated with gastrointestinal cancer. ODC is the key enzyme in polyamine synthesis and a regulator of cell proliferation. We performed gastric resections on 48 Wistar rats to induce spontaneous gastric cancer; half of these animals were given a normal diet, and the other half received a diet supplemented with NaHCO(3). Twenty-four unoperated rats served as a control group. The surgical procedure per se led to a significant rise in mucosal expression of COX-2 and an associated increase in cell proliferation. However, the COX-2 level in gastric mucosa was not further affected by dietary supplementation of carbonate. Interestingly, nontransformed gastric mucosa in the operated rats receiving a carbonate-supplemented diet showed a pronounced increase in ODC expression that was strongly correlated with a further enhanced cell proliferation. These results indicate that carbonate ions, which represent a major constituent of intestinal reflux into the stomach, increase the expression of ODC and thereby enhance cell proliferation in nontransformed mucosa, and consequently elevate the risk of gastric cancer.

-765G > C COX-2 polymorphism may be a susceptibility marker for gastric adenocarcinoma in patients with atrophy or intestinal metaplasia

AIM: To investigate the relationship between the -765G > C COX-2 polymorphism and the development of different gastric lesions: atrophy or intestinal metaplasia and gastric adenocarcinoma.

METHODS: A cross-sectional study was performed involving 320 Portuguese individuals (210 without evidence of neoplastic disease, 73 patients with gastric adenocarcinomas and 37 with atrophy or intestinal metaplasia) using a PCR-RFLP method.

RESULTS: -765C allele was overrepresented in the patients with gastric adenocarcinoma (51%) when compared either with the control group (38%) or patients with atrophy or intestinal metaplasia (27%). Callele was found to be very common in our population (0.22), and a multivariate logistic regression analysis revealed nearly 3-fold increased risk for the progression to gastric adenocarcinoma in patients with atrophy or intestinal metaplasia carrying the -765C allele (OR = 2.67, 95% CI = 1.03-6.93; P = 0.04).

CONCLUSION: -765C carrier status should be considered as another susceptibility marker for gastric adenocarcinoma development in patients with atrophy or intestinal metaplasia.

Risk assessment in relatives of gastric cancer patients: hyperproliferation, genetics, and Helicobacter pylori infection

Approximately 10% of cases of gastric cancer present with some kind of familial aggregation, but only 1-3% of gastric carcinomas arise as a result of clearly defined genetic syndromes that require genetic counselling and aggressive preventative measures. In the remaining families, no specific abnormalities, either genetic, biochemical or histological, responsible for the increased risk have been identified. However, several lines of evidence suggest that the increased cancer risk in first-degree relatives of gastric cancer probands is mostly dependent on Helicobacter pylori infection clustering.