Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0596263 (carcinogenesis)
 64,820 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Helicobacter pylori infection is associated with histological gastritis, gastric atrophy, gastric cancer and mucosa-associated lymphoid tissue lymphoma in the stomach. However, gastric cancer only develops in a minority of infected individuals. Such clinical diversity is caused by variations in the interactions between H. pylori pathogenicity, host susceptibility, and environmental factors. Based on evidence from three prospective epidemiological studies, the International Agency for Research on Cancer and the World Health Organization (IARC/WHO) concluded in 1994 that H. pylori has a causal linkage to gastric carcinogenesis and is a definite carcinogen in humans. Two large-scale, prospective, epidemiological studies have recently been reported in Japan and have confirmed that H. pylori infection constitutes a high risk factor for the development of gastric cancer, at least in males. In order to obtain evidence that eradication of H. pylori leads to a reduction in the occurrence of gastric cancer, reversibility of precancerous lesions, gastric atrophy or intestinal metaplasia should be proven after eradication treatment. A biopsy specimen from the lesser curvature of the corpus is the most sensitive for evaluating the regression of gastric atrophy on histology, and the evaluation needs be conducted at least 13 months after treatment. In a Mongolian gerbil model with or without low-dose chemical carcinogens, it has been demonstrated that H. pylori can lead to the development of gastric cancer. Experimental studies have elucidated that virulence factors of H. pylori interact with gastric epithelial cell signaling related to carcinogenesis. The cag pathogenicity island (cagPAI) is a major virulence gene cluster; it encodes the type IV secretion machinery system forming a cylinder-like structure. The CagA protein is translocated into target cells via this secretion system and induces a hummingbird phenotype, a growth factor-like effect. The other gene products are probably translocated into target cells and accelerate cellular proliferation and apoptosis. The molecular mechanism of the interaction between H. pylori and gastric epithelial cells may provide a new strategy for effective prevention of the development of gastric cancer induced by H. pylori infection.
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PMID:Development of gastric cancer associated with Helicobacter pylori infection. 1530 9

Clinical outcomes of Helicobacter pylori infection are diverse and caused by the variability of H. pylori virulence factors, host susceptibility, environmental factors and their interactions. Prospective epidemiological studies have clearly shown the relationship between H. pylori infection and gastric cancer. In addition, studies in animal models such as Mongolian gerbils with or without the addition of low-dose chemical carcinogens demonstrated that H. pylori infection can develop gastric carcinoma. Experimental studies have shown that virulence factors of H. pylori interact with gastric epithelial cell signaling related to carcinogenesis. While the effect of H. pylori eradication on prevention of such tumors in chronic H. pylori carriers is still controversial, progress has been made in therapy especially of gastric lymphoma with well tolerated chemotherapeutic regimen.
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PMID:Helicobacter pylori and gastric malignancies. 1534 4

Gastric adenocarcinoma is one of the most common cancers in Asian countries including China. Although its incidence rates in the West are lower than that in Asia, gastric cancer is still a major health problem worldwide, being second only to lung cancers in the number of deaths it causes. Helicobacter pylori infection has been identified as the major pathogen, but the detailed pathogenesis of gastric carcinoma remains elusive. Due to the lack of suitable and specific biomarkers for early detection, most cases of the disease are diagnosed at late stages and the survival rate is low. In this study, we used a proteomic approach to globally analyze the protein profiles of paired surgical specimens of primary gastric adenocarcinoma and nontumor mucosa aiming at identifying specific disease-associated proteins as potential clinical biomarkers and for carcinogenetic study. Compared to nontumor tissues, multiple protein alterations were found in tumor tissues. Some of these alterations involve variations in the expression of cytoskeleton proteins, including an increase in cytokeratin 8 and tropomyosin isoform and a decrease in cytokeratin 20. Co-up-regulations of heat-shock proteins and glycolytic enzymes were observed in tumor tissues, indicating self-protective efforts of cells and the growing energy requirement during malignant transformation. Diverse regulations also occurred with proteins involved in cell proliferation and differentiation, such as GMP reductase 2 and creatine kinase B, and proteins bearing potential tumor suppressor activities, including prohibitin and selenium binding protein 1. More interestingly, a human stomach-specific protein, 18 kDa antrum mucosa protein, was found to be dramatically under-expressed in cancer tissues, implicating a possible special pathological role for this protein in gastric carcinogenesis. Further comprehensive evaluation by globally considering the altered factors may result in the discovery of a biomarker index for effective assessment of the disease and may provide in-depth information for better understanding the pathogenesis of gastric cancer.
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PMID:Diverse proteomic alterations in gastric adenocarcinoma. 1537 96

Helicobacter pylori infection has an association with histological gastritis, gastric atrophy, gastric cancer, and mucosa-associated lymphoid tissue (MALT) lymphoma in the stomach. Gastric cancer occurs in only a minority of infected individuals, however. Such clinical diversities are caused by variations of H. pylori pathogenicity, host susceptibility, environmental factors, and interactions of these factors. By three prospective epidemiological studies, the International Agency for Research on Cancer, World Health Organization (IARC/WHO) concluded in 1994 that H. pylori had a causal linkage to gastric carcinogenesis and is a definite carcinogen in humans. In addition, the Mongolian gerbil model with or without low-dose chemical carcinogens demonstrated that H. pylori infection could develop into gastric cancer. The experimental studies have elucidated that virulence factors of H. pylori have an interaction with gastric epithelial cell signaling related to carcinogenesis. The cag pathogenicity island (cagPAI) is a major virulence gene cluster and codes the type IV secretion machinery system, forming a cylinder-like structure. The CagA protein is translocated into target cells via this secretion system and induces a hummingbird morphology, growth factor-like effect. The other gene products are probably translocated into target cells and accelerate cellular proliferation and apoptosis. Understanding the molecular mechanism of the interaction between H. pylori and gastric epithelial cells will provide us with a new strategy for effective prevention of the development of gastric cancer induced by H. pylori infection.
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PMID:Helicobacter pylori infection and gastric cancer. 1544 6

Studies suggest that IL-1beta (encoded by IL-1B gene) is a pro-inflammatory cytokine and potent inhibitor of gastric acid secretion, which is proposed as a key determinant in gastric carcinogenesis. Two potentially functional polymorphisms (C-31T and T-511C) in the IL-1B promoter were suggested to be correlated with alteration of Helicobacter pylori infection and IL-1beta expression and therefore may be associated with risk of gastric cancer. To test the hypothesis that these two polymorphisms are associated with gastric cancer risk, we performed a case-control study of 280 histologically confirmed gastric cancer patients and 258 age, sex frequency-matched cancer-free controls in a Chinese population. Multivariate logistic regression analyses revealed that the risks (adjusted odds ratio [OR] and 95% confidence interval [CI]) associated with the IL-1B variant genotypes were 1.64 (95% CI, 1.01-2.66) for -31TT and 1.52 (95% CI, 0.91-2.54) for -511CC, respectively, compared with their wild-type homozygotes. The risks were significantly more evident in individuals with H. pylori infection (adjusted OR, 2.14; 95% CI, 1.13-4.06 for -31TT; adjusted OR, 2.00; 95% CI, 1.02-3.89 for -511CC), which was consistent with the biological effects of IL-1beta. When we used the haplotype analyses and assumed the IL-1B -31T and -511C as risk alleles, no synergistic effect was found between these two loci. These findings indicate that these two IL-1B promoter variants may contribute to the risk of developing gastric cancer in the Chinese population, especially in individuals with H. pylori infection.
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PMID:Interleukin-1B gene promoter variants are associated with an increased risk of gastric cancer in a Chinese population. 1629 15

Helicobacter pylori infection and the cytokine-mediated inflammatory responses play important roles in gastric cancer pathogenesis. This case control study was conducted to assess the association between genetic polymorphisms in interleukin (IL)-1B, IL-1RN, IL-8, IL-10 and tumor necrosis factor alpha (TNFalpha), which are involved in H.pylori infection, and risk of gastric cancer. Genotypes were determined by PCR-based denaturing high-performance liquid chromatography analysis and direct DNA sequencing in 250 incident cases with gastric cancer and 300 controls recruited in Northern China. Serum levels of anti-H.pylori IgG and IgA were measured by enzyme-linked immunosorbent assay to indicate H.pylori infection. We found that the risk of gastric cancer was significantly elevated in subjects with the IL-8-251 AA [adjusted odds ratio (OR) 2.02; 95% confidence interval (CI) 1.27-3.21] or IL-10-1082 G (OR 2.02; 95% CI 1.24-3.29) or TNFalpha-308 AG (OR 1.81; 95% CI 1.04-3.14) genotype. An elevated risk of gastric cancer was observed in subjects with H.pylori infection and the IL-8-251 AA genotype (OR 2.54; 95% CI 1.38-4.72) or IL-10-1082 G carriers (OR 2.62; 95% CI 1.42-4.93). An increased OR was also suggested for IL-1B-31 and TNFalpha-238, but confidence intervals included the null value. There was no evidence of increased risk for any of the other polymorphisms evaluated. These findings suggest that genetic polymorphisms in IL-8, IL-10 and TNFalpha may play important roles in developing gastric cancer in the Chinese population.
Carcinogenesis 2005 Mar
PMID:Genetic polymorphisms of interleukin (IL)-1B, IL-1RN, IL-8, IL-10 and tumor necrosis factor {alpha} and risk of gastric cancer in a Chinese population. 1557 81

Helicobacter pylori infection is a known risk factor of gastric carcino-genesis. This article presents early molecular alterations associated with H. pylori chronic gastritis and advances in the molecular characterization of preneoplastic intestinal metaplasia (IM) and premalignant gastric mucosal lesions. H. pylori infection induces changes in gene expression, genomic instability and accumulation of gene mutations in the stomach epithelium. Mutations, including LOH and microsatellite instability, and gene hypermethylation are seen not only in gastric cancer, but are already detectable in IM and gastric dysplasia/adenoma. Recent reports using microarray expression analysis identified several gastric epithelial genes that are regulated by H. pylori. Among the many genes showing altered epithelial expression in response to H. pylori, some might be useful as markers to assess gastric cancer risk. Profiles of mutagenesis and gene expression in IM and dysplasia/adenoma have been characterized and represent potential markers of preneoplastic and premalignant lesions during gastric carcinogenesis.
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PMID:Molecular markers in Helicobacter pylori-associated gastric carcinogenesis. 1574 38

Since the discovery that Helicobacter pylori infection leads to gastric cancer, other chronic bacterial infections have been shown to cause cancer. The bacterial and host molecular mechanisms remain unclear. However, many bacteria that cause persistent infections produce toxins that specifically disrupt cellular signalling to perturb the regulation of cell growth or to induce inflammation. Other bacterial toxins directly damage DNA. Such toxins mimic carcinogens and tumour promoters and might represent a paradigm for bacterially induced carcinogenesis.
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PMID:Opinion: Bacterial toxins and cancer--a case to answer? 1580 96

Helicobacter pylori infection is well accepted to be a very important factor for the development of gastric carcinogenesis in the human stomach. In Mongolian gerbils treated with chemical carcinogens, H. pylori infection enhances glandular stomach carcinogenesis, and eradication of infection and results in curtailment of enhancing effects, particularly at early stages of associated inflammation. A high-salt diet exacerbates the effects of H. pylori infection on gastric carcinogenesis, and these two factors act synergistically to promote the development of gastric cancers in this animal model. However, the bacterium exerts the greater effects. Early acquisition significantly increases gastric chemical carcinogenesis in Mongolian gerbils, as compared to later infection. While heterotopic proliferative glands, hyperplastic and dilated glands localized beneath the muscularis mucosae, frequently develop with H. pylori infection alone in this animal model, they obviously regress on eradication, suggesting a relation to severe gastritis, rather than a malignant character. Furthermore, endocrine cells, positive for chromogranin A, are observed in the heterotopic proliferative glands, in contrast to cancerous lesions which lack endocrine elements. In conclusion, H. pylori is not an initiator, but rather a strong promoter of gastric carcinogenesis, whose eradication, together with reduction in salt intake, might effectively prevent gastric cancer development.
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PMID:Role of Helicobacter pylori in gastric carcinogenesis: the origin of gastric cancers and heterotopic proliferative glands in Mongolian gerbils. 1581 Sep 39

Gastric cancer is a multifactorial disease. Helicobacter pylori infection, host genetic factors and dietetic factors play an important role in the development of gastric cancer. Individuals with a positive family history of gastric cancer and/or pro-inflammatory polymorphisms of the interleukin-1 and tumor necrosis factor A genes infected by H. pylori virulent strains (cagA-, vacA s1-, vacA m1- and babA2-positive) have the highest risk of gastric cancer development. Diets rich in salted and smoked food and poor in fresh fruit and vegetables favor gastric carcinogenesis. Genetic combined with bacterial and host genotyping may allow for the identification of patients at high risk of gastric cancer who can benefit from preventive eradication therapy.
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PMID:Gastric cancer: who is at risk? 1581 51


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