- Research article
- Open Access
- Open Peer Review
Association of IL1B -511C/-31T haplotype and Helicobacter pylori vacA genotypes with gastric ulcer and chronic gastritis
© Martínez-Carrillo et al; licensee BioMed Central Ltd. 2010
- Received: 20 April 2010
- Accepted: 27 October 2010
- Published: 27 October 2010
The association between proinflammatory cytokine gene polymorphisms and gastric diseases related to Helicobacter pylori varies by population and geographic area.
Our objective was to determine if the IL-1B -511 T>C and -31 C>T polymorphisms and H. pylori vacA genotypes are associated with risk of chronic gastritis and gastric ulcer in a Mexican population.
We conducted endoscopic studies in 128 patients with symptoms of dyspepsia. We took two biopsies from the body, antrum, or ulcer edge from each patient, and classified our histopathological findings according to the Sydney System. H. pylori infection and vacA genotyping were accomplished via PCR from total DNA of the gastric biopsies. We confirmed the presence of anti-H. pylori serum IgG and IgM in 102 control subjects. In both case subjects and control subjects, the IL-1B -511 T>C polymorphism was genotyped by PCR-RFLPs and the IL-1B -31 C>T polymorphism was genotyped by pyrosequencing.
Sixty-two point seven (62.7%) of the 102 control subjects were H. pylori-seropositive. Among the case subjects, 100 were diagnosed with chronic gastritis and 28 with gastric ulcer. We found that 77% of the patients with chronic gastritis and 85.7% of the patients with gastric ulcer were H. pylori-positive. The predominant H. pylori genotype was vacA s1m1 (58.4%) and the most frequent subtype was vacA s1. The -511 TC, (rs16944 -511 T>C) genotype and the -511C allele were associated with chronic gastritis (OR = 3.1, 95% CI = 1.4-6.8 and OR = 3.0, 95% CI = 1.4-6.0, respectively). The subjects carrying -31T (rs1143627 -31 C>T) were found to be at a higher risk of having chronic gastritis (OR = 2.8, 95% CI = 1.3-5.8). The IL-1B -511C/-31T haplotype was associated with chronic gastritis (OR = 2.1, 95% CI = 1.2-3.8) but not with gastric ulcer.
The H. pylori vacA genotypes identified herein were similar to those reported for other regions of Mexico. The vacA s1m1 genotype was not associated with gastric ulcer. In the southern Mexican population, the IL-1B -511C and -31T alleles and the -511C/-31T and -511T/-31T haplotypes are associated with increased risk of chronic gastritis and gastric ulcer.
- Gastric Ulcer
- Pylorus Infection
- Stomach Cancer
- Chronic Gastritis
Helicobacter pylori infection is related to the inflammatory response of the gastric mucosa. While most infected individuals remain asymptomatic, persistent colonization and chronic inflammation increase the risk of developing atrophic gastritis, peptic ulcers, and distal gastric adenocarcinoma . The development of chronic gastritis is the initiating event in the process that leads to stomach cancer. The risk of malignancy increases with severity, chronicity, and duration of the inflammatory process [2, 3]. Clinical outcome of H. pylori infection is determined by the genetic characteristics of the host and bacteria as well as environmental factors . While H. pylori is considered to be a class I carcinogen, it is accepted that some genotypes have greater virulence. The strains that express cytotoxin-associated gene A (CagA) and large quantities of vacuolating cytotoxin (VacA) are most frequently found in patients with peptic ulcers and gastric carcinoma [2, 5, 6]. It has been observed that H. pylori vacA s1/m1 strains produce high levels of the cytotoxin, strains s1/m2 produce moderate levels, and strains s2/m2 produce little or no toxin [7, 9]. The vacA s1 subtype is related to higher disease severity and a higher risk of developing ulcers and stomach cancer [5, 6, 10].
H. pylori induce production of IL-1β in the gastric mucosa. IL-1β modulates the expression of other proinflammatory cytokine genes such as TNF-α, IL-2, IL-6 and IL-12, which increase the magnitude of inflammation . The concentration of IL-1β produced by the inflamed epithelium is influenced by two biallelic polymorphisms in positions -511T>C (rs16944) and -31C>T (rs1143627). These polymorphisms are in almost total genetic disequilibrium, and -31 is a TATA-box polymorphism that significantly affects DNA-protein interactions in vitro. Thus, these single-nucleotide polymorphisms (SNPs) can modulate production of IL-1β, directly affecting transcription [12, 13]. Given that IL-1β is a strong inhibitor of gastric acid secretion and may contribute to dispersion of H. pylori from the pylorus to the corpus of the stomach, polymorphisms in the IL-1β gene can be considered a key genetic factor in determining the pattern of gastritis that develops and one risk of malignant transformation [13, 14]. The IL-1B -511T and -31C alleles are associated with high levels of the cytokine and with severe inflammation or stomach cancer, in comparison to -511C and -31T, which are associated with low levels of IL-1β. This association with H pylori infection or stomach cancer has not been significant in all populations [2, 4, 6, 11, 13–20].
In combination, bacterium virulence factors and IL-B polymorphisms (cagA+/vacA+/IL-1B-511T/IL-RN*2) are associated with severe histological changes in the gastric mucosa of some populations [1, 4]. However, the variability of results across populations and geographic areas has been a source of ongoing controversy [2, 13, 14]. While gastritis, ulcer, and duodenitis constitute the fourth leading cause of disease in the Mexican population , the genetic basis for inter-individual variations in inflammatory response and cytokine production, in the context of H. pylori infection, has not been well studied in the Mexican population.
Genotyping of H. pylori vacA and IL-1B polymorphisms could be important in the early identification of individuals at high risk for developing severe gastric diseases. The objective of this study was to evaluate the relationship between IL-1B -511 T>C and -31 C>T polymorphisms and the presence of chronic gastritis and gastric ulcer, and to analyze the relationship of H. pylori vacA genotypes with gastric ulcer.
We studied 128 patients subjected to an endoscopic study in the Specialized Unit for Gastroenterology Endoscopy in the city of Chilpancingo, in the state of Guerrero, Mexico, from April 2007 to May 2008. All subjects suffered from functional dyspepsia, epigastric pain, and ulcerative syndrome. Patients who had not received H. pylori erradication therapy, and had not been treated with proton pump inhibitors nor with gastric pH neutralizers during the two months prior to the endoscopy were included in the study. We also studied 102 subjects without dyspepsia symptoms, from the same population as the cases, with no history of H. pylori infection or gastroduodenal diseases. In both groups, we excluded subjects under non-steroidal anti-inflammatory drug (NSAID) treatment.
Informed consent was obtained from participants or their parents. Participants' eating habits, socio-demographic factors, family history of gastritis or ulcers, alcohol consumption, and smoking habits were recorded via surveys. The study was approved by the Bioethics Committee of the Universidad Autónoma de Guerrero.
Endoscopy and gastric histology
For each patient, endoscopy was carried out using a video processor and video gastroscope (Fujinon, Wayne, NJ, USA). From each patient, we took two biopsies from the antrum, corpus, or ulcer edge; one specimen was immediately fixed in formalin for histological testing and the other was placed in buffer solution (Tris 10 mM pH 8.0, EDTA 20 mM pH 8.0, SDS 0.5%) for H. pylori diagnosis. The biopsies intended for H. pylori detection were kept at -20°C until processing. The histological sections were stained with hematoxylin-eosin and evaluated by a pathologist using the updated Sydney System criteria . Endoscopic observation and histopathological confirmation were used to determine patient pathology.
Blood samples (5 ml) were taken from all control subjects. The serum was tested for IgG and IgM anti-H. pylori by enzyme-linked immunosorbent assay (ELISA; International Immuno-Diagnostics, Foster City, CA, USA) according to the manufacturer's instructions. The sensitivity and specificity of this method are 96% and 97%, respectively. A subject was considered H. pylori-positive if we detected at least one of the two antibodies.
H. pylori detection and vacAgenotyping
Total DNA was extracted from the gastric biopsies of each patient via the phenol:chloroform:isoamilic alcohol technique, after digestion with proteinase K .
In the cases, the presence of H. pylori was detected by polymerase chain reaction (PCR) for the 16S rRNA gene. We used 150 ng total DNA, 2.5 mM MgCl2, 0.2 mM dNTPs (Invitrogen, Carlsbad, CA, USA), 10 pmol of each oligonucleotide, and 1 U Platinum®Taq DNA Polymerase (Invitrogen, Carlsbad, CA, USA) in a final volume of 15 μL. The H. pylori-positive samples were subjected to detection of subtypes of vacA by PCR. For PCR of the signal region (s) and medium (m), we used 300 ng total DNA, 1.5 mM MgCl2, 0.2 mM dNTP, 15 pmol of each oligonucleotide, and 1 U Platinum®Taq DNA Polymerase in a final volume of 20 μL. The amplification protocols were previously described by Atherton et al. and Park et al. [24, 25]. In each PCR, we used DNA from strain ATCC43504, vacA s1/m1 as positive control for H. pylori and for vacA genotypes. The template DNA was substituted with sterile deionized water in the negative control. All PCRs were conducted in a Mastercycler® Ep gradient thermal cycler (Eppendorf, Hamburg, Germany).
IL-1B-511 T>C and -31 C>T genotyping
We obtained peripheral blood DNA from the control subjects using Miller's technique . Genotyping of the IL-1B -511 T>C SNP was done via PCR-restriction fragment length polymorphism (RFLP) as previously described . Eight-microliter of PCR product were digested with 2 U AvaI (New England Biolabs, Ipswich, MA, USA) at 37°C for 12 h and analyzed in 2% agarose gels. The IL-1B -31 C>T SNP was genotyped by pyrosequencing, following the methodology described by Pérez et al. . Of the 230 samples processed, 12% were subjected to PCR-RFLP for genotype verification.
We applied X2 or Fisher's exact test to compare frequencies between groups, and analysis of variance (ANOVA) or Kruskal-Wallis tests to compare means and medians, respectively. In the control group, we evaluated the Hardy-Weinberg Equilibrium (HWE) for IL-1B polymorphisms. To determine the association of IL-1B polymorphisms with chronic gastritis and gastric ulcer, we evaluated binomial and polynomial logistic regression models, and used multiplicative interaction models to study the effect of possible interactions between H. pylori and IL-1B genotypes and gastric ulcer. We calculated Lewontin's D' statistic for linkage disequilibrium between loci. Two-tailed statistical tests were conducted with a significance level of 5% using STATA 10 software.
Socio-demographic characteristics in cases and controls.
(n = 102)
(n = 100)
(n = 28)
Age (mean ± sd; years)
29.8 ± 11
46.1 ± 14.6
56.3 ± 17.1
Education [mean (range); years]
Geographical area n(%)
Family history of gastritis and/or ulcer n(%)
Smoking habit n(%)
Current smoker or former smoker
Alcohol consumption n(%)
Consumes or consumed
H. pylori infection and vacAgenotypes
Genotype and alleles of H. pylor i vacA frequencies in cases.
Genotypes or alleles
s1m1 y s1m2
Not typed *
IL-1B -511 T>C and -31 C>Tpolymorphisms
Genotypic distribution and allelic frequencies of IL-1 B polymorphisms in cases and controls.
511 T>C SNP
-31 C>T SNP
Association of IL-1 B polymorphisms with chronic gastritis and gastric ulcer.
Haplotypes of IL-1 B SNPs and their association with gastritis and gastric ulcer.
To determine whether carriers of -511C and -31T alleles who were infected by H. pylori vacA s1 showed higher risk of gastritis or ulcer, the OR was calculated for the patients exposed to H. pylori vacA s1 within each group, as compared to those infected with H. pylori vacA s2. We did not observe significant association between infection with H. pylori vacA s1 with chronic gastritis or gastric ulcer in carriers of the IL-1B-511C and -31T alleles or their haplotypes (data not shown).
In patients with chronic gastritis, we only found genotypes vacA s1m1, s1m2, and s2m2. However the most virulent allele, vacAs1, was the most frequent in patients with both diseases. Our results agree with those reported by other authors and confirm that the s1m1genotype is in greatest circulation in Mexico [28–30]. The lack of significant association between vacA s1m1with gastric ulcer, as compared to chronic gastritis, may be explained by the presence of multiple factors giving rise to the disease and by the small sample size in our study.
Chronic infection with H. pylori induces hypochlorhydria, and this is a critical factor in the development of gastric pathology. Thus, the genetic factors in the host that influence acid secretion can also mediate the clinical progress of H. pylori infection. IL-1β is a powerful proinflammatory cytokine that is overexpressed in the presence of H. pylori and plays an important role in amplifying the inflammatory response to the infection [1, 6, 31, 32]. The biallelic polymorphisms in positions -31 and -511 of IL-1B influence cytokine expression; allele T in position -31 forms a TATA-Box that can potentiate and induce expression of IL-1β [32, 33]. It has been reported that the IL-1B -511T/IL-1B-31C alleles are significantly associated with the development of hypochlorhydria, H. pylori infection, gastritis, and stomach cancer, however the variability of results from studies conducted in various populations remain controversial [33–36].
Interestingly, in our study, the -511 TC/CC and -31 CT/TT IL-1B genotypes were associated with the presence of chronic gastritis and the presence of gastric ulcer when all cases were grouped (-511 TC/CC OR adjusted = 2.8, 95% CI = 1.6-5.1; -31 CT/TT OR adjusted = 2.9, 95% CI = 1.6-5.3). Greater risk of chronic gastritis and stomach cancer has also been reported in Japanese population with the -511CC genotype and in Chinese population with the CT genotype . In the Thai population, IL-1B genotype -511CC is considered a risk factor for stomach cancer . A previous study in a Japanese population showed that subjects with the -31TT genotype had a significantly higher risk of H. pylori infection (OR= 1.74, 95% CI = 1.15-5.63) than subjects with -31CT or -31CC genotypes. A similar result was obtained for H. pylori-seropositive Japanese-Brazilians (OR -31TT = 1.45, 95% CI = 1.02-2.07) [13, 39]. In a Korean population, the -31T polymorphism was found to be associated with stomach cancer ; and in Polish and Western Scottish populations, the -31T allele was found to be associated with both H. pylori infection and hypochlorhydria as well as a higher risk of stomach cancer . In a Spanish population, García-González et al. found that IL-1B -511 C/-31 T contributed to risk of duodenal ulcer .
In our study, the effect of the -31CT/TT and -511TC/CC genotypes on risk of chronic gastritis was greater when we adjusted for factors such as age, place of origin, schooling, smoking habits, family history of gastritis or gastric ulcer, and H. pylori infection. Therefore, the habits and lifestyles of the studied individuals modified the risk of developing chronic gastritis. Such findings support the multifactorial model of gastric pathology that includes the host, H. pylori, and the environment [13, 36, 39]. Given the OR values, it is likely that the same is true for gastric ulcer, but due to the small size of the sample it was not possible to obtain significant associations.
To our knowledge, this is the first study to examine the association of -511 T>C and -31 C>T SNPs in Mexican patients with chronic gastritis and gastric ulcer. Two prior studies found that the -31CC genotype was associated with stomach cancer as compared to the -31TT genotype (in the northeast region of Mexico, OR = 7.6, 95% CI = 1.73-46.9; in the southeast and central regions of Mexico, OR = 3.19, 95% CI = 1.05-9.68) [6, 41]. These differences might be the result of genomic diversity in the populations across different regions of Mexico. The sub-population in the northern region of Mexico has a greater contribution of European ancestry, while the population of Guerrero has a particularly dominant African ancestral contribution, with a minor European contribution and is genetically closer to the Zapotecs .
Chronic gastritis and gastric ulcer are part of the natural evolution to stomach cancer [3, 4], and it is possible that a similar phenomenon occurs in Mexico as has been observed in Asian populations, in which the distribution of IL-1B genotypes differs between the northern region, where there is a high prevalence of stomach cancer, and the southern region, where there is a low prevalence of stomach cancer [33–35, 43].
The information available on IL-1B alleles associated with diseases linked to H. pylori is controversial. While some researchers have found that IL-1B -511TT and IL-1B -31CC are proinflammatory [32, 44], others have found, with in vitro experiments and with stomach cancer patients infected with H. pylori, that the IL-1B -511C and IL-1B -31T alleles potentiate expression of IL-1β in the gastric mucosa [33, 45, 46]. The results of our work agree with those of Takagi et al. who found that the IL-1B -511CC/IL-1B -31TT genotypes potentiate cytokine production and are significantly associated with the clinical development of H. pylori infection .
Patients with chronic gastritis and gastric ulcer were infected predominantly with H. pylori vacA s1m1 genotype and the vacAs1 allelotype was the most frequent. In chronic gastritis the s1m1 y s1m2 genotypes tend to be associated in co-infections.
In the population of southern Mexico, -511C or -31T alleles and -511C/-31T or -511T/-31T haplotypes of IL-1B increase the risk of chronic gastritis and gastric ulcer.
The results of this study support the hypothesis that the combined effect of lifestyle, infection with virulent genotypes of H. pylori, and genetic factors of the host, such as IL-1B -511C/IL-1B -31T polymorphisms, can play an important role in development of chronic gastritis and gastric ulcer in the Mexican population of the state of Guerrero.
The authors wish to thank Elizabeth Rosales-Cruzaley as well as the nurses and support personnel of the Gastroenterologic Endoscopy Specialized Unit of Chilpancingo, who assisted in obtaining samples. We also want to thank Martín O. Morrugares Ixtepan, Specialist in Pathological Anatomy with subspecialty in Oncological Pathology, who was responsible for the histopathological diagnosis. The study was financed by the Secretaría de Educación Pública, via PIFI 2007 and the Programa de Apoyo a la Reincorporación de Exbecarios PROMEP 2007, key PROMEP UAGUER-EXB-096. During our study, Dinorah Nashely was a grant recipient of the Consejo Nacional de Ciencia y Tecnología de México. Finally, we would like to thank Dinorah Leyva-Illades (Texas A&M Health Science Center) for translating this manuscript to the English language.
- Rad R, Prinz C, Neu B, Neuhofer M, Zeitner Voland P, Becker I, Schepp W, Gerhard M: Synergistic effect of Helicobacter pylori virulence factors and interleukin-1 polymorphisms for the development of severe histological changes in the gastric mucosa. JID. 2003, 188: 272-280. 10.1086/376458.View ArticlePubMedGoogle Scholar
- Sierra R, Une C, Ramírez V, Alpízar-Alpízar W, González MI, Ramírez JA, De Mascarel A, Cuenca P, Pérez-Pérez G, Mégraud F: Relation of atrophic gastritis with Helicobacter pylori-CagA+ and interleukin-1 gene polymorphisms. World J Gastroenterol. 2008, 14: 6481-6487. 10.3748/wjg.14.6481.View ArticlePubMedPubMed CentralGoogle Scholar
- Fox JG, Wang TC: Inflammation, atrophy, and gastric cancer. J Clin Invest. 2007, 117: 60-69. 10.1172/JCI30111.View ArticlePubMedGoogle Scholar
- Peek RM, Blaser MJ: Helicobacter pylori and gastrointestinal tract adenocarcinomas. Nature. 2002, 2: 28-37.Google Scholar
- Zhang Z, Zheng Q, Chen X, Xiao S, Liu W, Lu H: The Helicobacter pylori duodenal ulcer promoting gene, dupA in China. BMC Gastroenterology. 2008, 8: 49-10.1186/1471-230X-8-49.View ArticlePubMedPubMed CentralGoogle Scholar
- Garza-González E, Bosques-Padilla FJ, El-Omar E, Hold G, Tijerina-Menchaca R, Maldonado-Garza HJ, Pérez-Pérez GI: Role of the polymorphic IL-1B, IL-1RN and TNF-A genes in distal gastric cancer in Mexico. Int J Cancer. 2005, 114: 237-241. 10.1002/ijc.20718.View ArticlePubMedGoogle Scholar
- Marciorkowska E, Roszko I, Kowalczuk O, Kaczmarski M, Chyczewski L, Kemona A: The evaluation of vacA gene allele frequency in Helicobacter pylori strains in adults and children in Podlaskies region. Folia Histochem Cytobiol. 2007, 45: 215-219.Google Scholar
- Caricio-Martins L, Oliveira-Corvelo TC, Demachki S, Araujo MTF, Baraúna-Assumpção M, Araujo-Jucá Vilar SC, Bonfim-Freitas F, Melo-Barbosa HP, Alves-Fecury A, Kelly-Costa do Amaral R, Batista-dos Santos SE: Clinical and pathological importance of vacA allele heterogeneity and cagA status in peptic ulcer disease in patients from North Brazil. Mem Inst Oswaldo Cruz. 2005, 100: 875-881.View ArticleGoogle Scholar
- Chang YH, Wang L, Lee MS, Cheng CW, Wu CY, Shiau MY: Genotypic characterization of Helicobacter pylori cagA and vacA from biopsy specimens of patients with gastroduodenal diseases. Mt Sinai J Med. 2006, 73: 622-626.PubMedGoogle Scholar
- Garza-González E, Bocanegra-García V, Bosques-Padilla FJ, Flores-Gutiérrez JP, Moreno F, Perez-Perez GI: mRNA levels of TLR4 and TLR5 are independent of H pylori. World J Gastroenterol. 2008, 14: 5306-5310. 10.3748/wjg.14.5306.View ArticlePubMedPubMed CentralGoogle Scholar
- Moorchung N, Srivastava AN, Gupta NK, Ghoshal UC, Achyut BR, Mittal B: Cytokine gene polymorphisms and the pathology of chronic gastritis. Singapore Med J. 2007, 48: 447-454.PubMedGoogle Scholar
- Kim SH, Mok JW, Kim HS, Joo CK: Association of -31T>C and -511 C>T polymorphisms in the interleukin 1 beta IL1B) promoter in Korean keratoconus patients. Mol Vis. 2008, 14: 2109-2116.PubMedPubMed CentralGoogle Scholar
- Uno M, Hamajima N, Ito LS, Oba S, Marie SKN, Shinjo SK, Onda H, Saito T, Takezaki T, Tajima K, Tominaga S: Helicobacter pylori seropositivity and IL-1B C-31T polymorphism among Japanese Brazilians. Int J Mol Med. 2002, 10: 321-326.PubMedGoogle Scholar
- Kato S, Onda M, Yamada S, Matsuda N, Tokunaga A, Matsukura N: Association of the interleukin-1β genetic polymorphism and gastric cancer risk in Japanese. J Gastroenterol. 2001, 36: 696-9. 10.1007/s005350170033.View ArticlePubMedGoogle Scholar
- Santtila S, Savinainen K, Hurme M: Presence of the IL-1RA allele 2 (IL1RN*2) is associated with enhanced IL-1β production in vitro. Scand J Immunol. 1998, 47: 195-198. 10.1046/j.1365-3083.1998.00300.x.View ArticlePubMedGoogle Scholar
- Hsu PI, Li CN, Tseng HH, Lai KH, Hsu PN, Lo GH, Lo CC, Yeh JJ, Ger LP, Hsiao M, Yamoaka Y, Hwang IR, Chen A: The Interleukin-I RN polymorphism and Helicobacter pylori infection in the development of duodenal ulcer. Helicobacter. 2004, 9: 604-613. 10.1111/j.1083-4389.2004.00277.x.View ArticleGoogle Scholar
- Al-Moundhri MS, Al-Nabhani M, Al-Bahrani B, Burney IA, Al-Madhani A, Ganguly SS, Al-Yahyaee SA, Grant CS: Interleukin-1β gene (IL-1B) and interleukin 1 receptor antagonist gene (IL-1RN) polymorphisms and gastric cancer risk in an Omani Arab population. Gastric Cancer. 2006, 9: 284-290. 10.1007/s10120-006-0392-5.View ArticlePubMedGoogle Scholar
- El-Omar EM: The importance of interleukin 1β in Helicobacter pylori associated disease. Gut. 2001, 48: 743-747. 10.1136/gut.48.6.743.View ArticlePubMedPubMed CentralGoogle Scholar
- Figueiredo C, Machado JC, Pharoah P, Seruca R, Sousa S, Carvalho R, Capelinha AF, Quint W, Caldas C, van Dooorn LJ, Carneiro F, Sobrinho-Simoes M: Helicobater pylori and Interleukin 1 genotyping: An opportunity to identify high-risk individuals for gastric carcinoma. J Natl Cancer Inst. 2002, 94: 1680-1686.View ArticlePubMedGoogle Scholar
- Pérez-Pérez GI, Garza-González E, Portal C, Olivares AZ: Role of cytokine polymorphisms in the risk of distal gastric cancer development. Cancer Epidemiol Biomarkers Prev. 2005, 14: 1869-73. 10.1158/1055-9965.EPI-04-0889.View ArticlePubMedGoogle Scholar
- Secretaría de Salud, Subsecretaría de Prevención y Promoción de la Salud. Centro Nacional de Vigilancia Epidemiológica y Control de Enfermedades. Dirección General de Epidemiología: Información epidemiológica de morbilidad. México. 2006Google Scholar
- Dixon MF, Genta RM, Yardley JH, Correa P: Classification and grading of gastritis. The updated Sydney system-International workshop on the histopathology of gastritis, Houston 1994. Am J Surg Pathol. 1996, 20: 1161-1181. 10.1097/00000478-199610000-00001.View ArticlePubMedGoogle Scholar
- Sambrook J, Russel D: Molecular Cloning a Laboratory Manual. 2001, EU: Col Spring Harbor Laboratory PressGoogle Scholar
- Atherton JC, Cao P, Peek RMR, Tummuru MKR, Blasser MJ, Cover TL: Mosaicism in vacuolating cytotoxin alleles of Helicobacter pylori. J Biol Chem. 1995, 270: 17771-17777. 10.1074/jbc.270.30.17771.View ArticlePubMedGoogle Scholar
- Park CY, Kwak M, Gutierrez O, Graham DY, Yamaoka Y: Comparison of genotyping Helicobacter pylori directly from biopsy specimens and genotyping from bacterial cultures. J Clin Microbiol. 2003, 41: 3336-3338. 10.1128/JCM.41.7.3336-3338.2003.View ArticlePubMedPubMed CentralGoogle Scholar
- Miller SA, Dykes DD, Polesky HF: A simple salting out procedure for extracting DNA from human nucleated cells. Nucleic Acids Res. 1988, 16: 1215-10.1093/nar/16.3.1215.View ArticlePubMedPubMed CentralGoogle Scholar
- Pérez-Pérez GI, Portal-Celhay C, Bosques-Padilla FJ, Garza-González E: Desarrollo de un protocolo de pirosecuenciación para la tipificación del polimorfismo -31 del gen de la interleucina 1β en el estudio del riesgo al desarrollo de cáncer gástrico. Rev Gastroenterol Mex. 2007, 72: 136-140.Google Scholar
- Morales-Espinoza R, Castillo-Rojas G, Gonzalez-Valencia G, Ponce-DeLeon S, Cravioto A, Atherton JC, López-Vidal Y: Colonization of Mexican patients by multiple Helicobacter pylori strains with different vacA and cagA genotypes. J Clin Microbiol. 1999, 3001-3004.Google Scholar
- Garza-González E, Bosques-Padilla FJ, Tijerina-Menchaca R, Pérez-Pérez GI: Characterisation of Helicobacter pylori isolates from the north-eastern region of Mexico. Clin Microbiol Infect. 2004, 10: 41-45. 10.1111/j.1469-0691.2004.00731.x.View ArticlePubMedGoogle Scholar
- Paniagua GL, Monroy E, Rodríguez R, Arroniz S, Rodríguez C, Cortés JL, Camacho A, Negrete E, Vaca S: Frequency of vacA, cagA and babA2 virulence markers in Helicobacter pylori strains isolated from Mexican patients with chronic gastritis. Ann Clin Microbiol Antimicrob. 2009, 8: 14-10.1186/1476-0711-8-14.View ArticlePubMedPubMed CentralGoogle Scholar
- Ruzzo A, Graziano F, Pizzagalli F, Santini D, Battistelli V, Panunzi S, Canestrari E, Catalano V, Humar B, Ficarelli R, Bearzi I, Cascinu S, Naldi N, Testa E, Magnani M: Interleukin 1B gene (IL-1B) and interleukin 1 receptor antagonist gene (IL-1RN) polymorphisms in Helicobacter pylori-negative gastric cancer of intestinal and diffuse histotype. Ann Oncol. 2005, 16: 887-92. 10.1093/annonc/mdi184.View ArticlePubMedGoogle Scholar
- El-Omar EM, Carrington M, Chow WH, McColl KE, Breamk JH, Young HA, Herrera J, Lissowska J, Yuan CC, Rothman N, Lanyon G, Martin M, Fraumeni JF, Rabkin CS: Interleukin-1 polymorphisms associated with increased risk of gastric cancer. Nature. 2000, 404: 398-402. 10.1038/35006081.View ArticlePubMedGoogle Scholar
- Chang YW, Jang JY, Kim NH, Won-Lee J, Jung-Lee J, Won-Jung W, Dong SH, Kim HJ, Kim BH, Lee JI, Chang R: Interleukin-1B (IL-1B) polymorphisms and gastric mucosal levels of IL-1β cytokine in Korean patients with gastric cancer. Int J Cancer. 2005, 114: 465-471. 10.1002/ijc.20724.View ArticlePubMedGoogle Scholar
- Kamangar F, Cheng C, Abnet CC, Rabkin CS: Interleukin-1B polymorphisms and gastric cancer risk--a meta-analysis. Cancer Epidemiol Biomarkers Prev. 2006, 15: 1920-8. 10.1158/1055-9965.EPI-06-0267.View ArticlePubMedGoogle Scholar
- Prinz C, Schwendy Voland P: H. pylori and gastric cancer: Shifting the global burden. World J Gastroenterology. 2006, 12 (Suppl 34): 5458-5464.View ArticleGoogle Scholar
- Saijo Y, Yoshioka E, Fukui T, Kawaharada M, Sata F, Sato H, Kishi R: H pylori seropositivity and cytokine gene polymorphisms. World J Gastroenterol. 2007, 13: 4445-4451.View ArticlePubMedPubMed CentralGoogle Scholar
- Matsukura N, Yamada S, Kato S, Tomtitchong P, Tajiri T, Miki M, Matsuhisa T, Yamada N: Genetic differences in interleukin-1 beta polymorphisms among four Asian populations: An analysis of the Asian paradox between H. pylori infection and gastric cancer incidence. J Exp Clin Cancer Res. 2003, 22: 47-55.PubMedGoogle Scholar
- Yamada S, Matsuhisa T, Makonkawkeyoon L, Chaidatch S, Kato S, Matsukura N: Helicobacter pylori infection in combination with the serum pepsinogen I/II ratio and interleukin-1b-511 polymorphisms are independent risk factors for gastric cancer in Thais. J Gastroenterol. 2006, 41: 1169-1177. 10.1007/s00535-006-1951-6.View ArticlePubMedGoogle Scholar
- Katsuda N, Hamajima N, Tamakoshi A, Wakai K, Matsuo K, Saito T, Tajima K, Tominaga S: Helicobacter pylori seropositivity and the myeloperoxidase G-463A polymorphism in combination with interleukin-1B C-31T in Japanese health checkup examinees. Jpn J Clin Oncol. 2003, 33: 192-197. 10.1093/jjco/hyg034.View ArticlePubMedGoogle Scholar
- García-González MA, Lanas A, Savelkoul PHM, Santolaria S, Benito R, Crusius JBA, Peña AS: Association of interleukin 1 gene family polymorphisms with duodenal ulcer disease. Clin Exp Immunol. 2003, 134: 525-531. 10.1111/j.1365-2249.2003.02325.x.View ArticlePubMedPubMed CentralGoogle Scholar
- Sicinschi LA, López-Carrillo L, Camargo MC, Correa P, Sierra RA, Henry RR, Jia C, Zabaleta J, Piazuelo MB, Schneider BG: Gastric cancer risk in a Mexican Population: Role of Helicobacter pylori cagA positive infection and polymorphisms in interleukin-1 and -10 genes. Int J Cancer. 2006, 118: 649-657. 10.1002/ijc.21364.View ArticlePubMedGoogle Scholar
- Silva-Zolezzi I, Hidalgo Miranda A, Estrada Gil1 J, Fernández López JC, Uribe Figueroa L, Contreras A, Balam Ortiz E, del Bosque Plata L, Lara C, Velázquez Fernández D, Goya R, Hernández Lemus E, Dávila C, Barrientos E, March S, Jiménez-Sánchez G: Análisis de la diversidad genómica en las poblaciones mestizas mexicanas para desarrollar medicina genómica en México. Proc Natl Acad Sci U S A. 2009, 106 (21): 8611-8616.View ArticlePubMedPubMed CentralGoogle Scholar
- Furuta T, El-Omar EM, Xiao F, Shirai N, Takashima M, Sugimura H: Interleukin 1beta polymorphisms increase risk of hypochlorhydria and atrophic gastritis and reduce risk of duodenal ulcer recurrence in Japan. Gastroenterology. 2002, 123: 92-105. 10.1053/gast.2002.34156.View ArticlePubMedGoogle Scholar
- Hwang IR, Kodama T, Kikuchi S, Sakai K, Peterson LE, Graham DY, Yamaoka Y: Effect of interleukin 1 polymorphisms on gastric mucosal interleukin 1β production in Helicobacter pylori infection. Gastroenterology. 2002, 123: 1793-803. 10.1053/gast.2002.37043.View ArticlePubMedGoogle Scholar
- Chakravortya M, Datta D, Choudhuryb A, Roychoudhurya S: IL1B promoter polymorphism regulates the expression of gastric acid stimulating hormone gastrin. Int J Biochem Cell Biol. 2009, 41: 1502-1510. 10.1016/j.biocel.2008.12.017.View ArticleGoogle Scholar
- Zeng ZR, Hu PJ, Hu S, Pang RP, Chen MH, Ng M, Sung JJY: Association of interleukin 1B gene polymorphisms and gastric cancers in high and low prevalence regions in China. Gut. 2003, 52: 1684-9. 10.1136/gut.52.12.1684.View ArticlePubMedPubMed CentralGoogle Scholar
- Takagi A, Deguchi R, Kobayashi K, Miwa T: Cytokine expressions and H. pylori-associated gastric mucosal lesion. Keio J Med. 2002, 51 (Suppl 2): 51-2.View ArticlePubMedGoogle Scholar
- The pre-publication history for this paper can be accessed here:http://www.biomedcentral.com/1471-230X/10/126/prepub
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