Con SA, Takeuchi H, Con-Chin GR, Con-Chin VG, Yasuda N, Con-Wong R. Role of bacterial and genetic factors in gastric cancer in Costa Rica. World J Gastroenterol 2009; 15(2): 211-218
Corresponding Author of This Article
Dr. Sergio A Con, Centro Digestivo Doctores Con-Mediplaza, Pavas 245-1200, San José, Costa Rica. firstname.lastname@example.org
Article-Type of This Article
Open-Access Policy of This Article
This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
World J Gastroenterol. Jan 14, 2009; 15(2): 211-218 Published online Jan 14, 2009. doi: 10.3748/wjg.15.211
Role of bacterial and genetic factors in gastric cancer in Costa Rica
Sergio A Con, Hiroaki Takeuchi, Gil R Con-Chin, Vicky G Con-Chin, Nobufumi Yasuda, Reinaldo Con-Wong
Sergio A Con, Gil R Con-Chin, Vicky G Con-Chin, Reinaldo Con-Wong, Centro Digestivo Doctores Con-Mediplaza, Pavas 245-1200, San José, Costa Rica
Sergio A Con, Hiroaki Takeuchi, Department of Clinical Laboratory Medicine, Kochi Medical School, Kochi University, Nankoku-city, Kochi 783-8505, Japan
Nobufumi Yasuda, Department of Public Health, Kochi Medical School, Kochi University, Nankoku-city, Kochi 783-8505, Japan
ORCID number: $[AuthorORCIDs]
Author contributions: Con SA designed and performed the research and wrote the paper; Takeuchi H, Con-Chin GR, Con-Chin VG and Con-Wong R contributed reagents/analytic tools; Yasuda N analyzed the data; Takeuchi H and Con-Wong R revised the paper.
Correspondence to: Dr. Sergio A Con, Centro Digestivo Doctores Con-Mediplaza, Pavas 245-1200, San José, Costa Rica. email@example.com
Received: August 1, 2008 Revised: October 22, 2008 Accepted: October 29, 2008 Published online: January 14, 2009
AIM: To evaluate several risk factors for gastric cancer (GC) in Costa Rican regions with contrasting GC incidence rate (GCIR).
METHODS: According to GCIR, 191 Helicobacter pylori (H pylori)-positive patients were classified into groups A (high GCIR, n = 101) and B (low GCIR, n = 90). Human DNA obtained from biopsy specimens was used in the determination of polymorphisms of the genes coding for interleukin (IL)-1&bgr; and IL-10 by PCR-RFLP, and IL-1RN by PCR. H pylori DNA extractions obtained from clinical isolates of 83 patients were used for PCR-based genotyping of H pylori cagA, vacA and babA2. Human DNA from gastric biopsies of 52 GC patients was utilized for comparative purposes.
RESULTS: Cytokine polymorphisms showed no association with GCIR variability. However, gastric atrophy, intestinal metaplasia and strains with different vacA genotypes in the same stomach (mixed strain infection) were more frequently found in group A than in group B, and cagA and vacA s1b were significantly associated with high GCIR (P = 0.026 and 0.041, respectively). IL-1&bgr;+3954_T/C (OR 2.1, 1.0-4.3), IL-1RN*2/L (OR 3.5, 1.7-7.3) and IL-10-592_C/A (OR 3.2, 1.5-6.8) were individually associated with GC, and a combination of these cytokine polymorphisms with H pylori vacA s1b and m1 further increased the risk (OR 7.2, 1.4-36.4).
CONCLUSION: Although a proinflammatory cytokine genetic profile showed an increased risk for developing GC, the characteristics of H pylori infection, in particular the status of cagA and vacA genotype distribution seemed to play a major role in GCIR variability in Costa Rica.
Citation: Con SA, Takeuchi H, Con-Chin GR, Con-Chin VG, Yasuda N, Con-Wong R. Role of bacterial and genetic factors in gastric cancer in Costa Rica. World J Gastroenterol 2009; 15(2): 211-218
Costa Rica has one of the highest age-adjusted incidence and mortality rates for gastric cancer. In fact, this country reported the highest age-adjusted gastric cancer mortality rate in males and females over the period 1983-1997, out of a total of 30 countries, including Japan and Chile.
Costa Rica has regions with contrasting gastric cancer incidence rates (GCIR). Topographically, the central part of the country is predominantly composed of regions with high GCIR while coastal areas are largely characterized by low GCIR. Population density varies according to geographic area. While in coastal regions the population density is around 30 persons per square km, in the central regions of San Jose and Cartago, it ranges from 140 to 270 persons per square km. Cultural, behavioral and dietary patterns are very similar throughout the country, regardless of population density. The predominant ethnic group is the criollo, which has Spanish ancestry. In spite of these homogeneous patterns, the GCIR in Costa Rica shows a distinctive regional variation. Several environmental factors such as the components of drinking water, soil and nutrients have been compared in contrasting GCIR regions; however, none of these factors was significantly associated with GCIR variation in the country.
The cause of gastric cancer is thought to be multifactorial. A higher incidence of gastric cancer in blood type A subjects than in those with other blood types was reported as early as the 1950’s. Several decades later, after the discovery of Helicobacter pylori (H pylori), which is a Gram-negative microaerobic bacterium that persistently colonizes the human gastric mucosa, it was reported that H pylori-positive subjects are believed to have a two- to three-fold increased risk of developing gastric cancer when compared with H pylori-negative subjects[8–11]. The risk is even higher in subjects infected with strains co-expressing the H pylori cagA, vacA s1 and babA2 genes[12–15]. Recently, cytokine gene polymorphisms of the host, IL-1&bgr;, IL-1RN and IL-10, in response to H pylori infection, have been associated with an increased risk for developing gastric cancer[16–21]. Moreover, it has been suggested that an interaction between a host’s immunological defenses, environmental and H pylori virulence factors play a main role in the development of gastric cancer.
We previously reported that the presence of serum CagA antibody was found to be significantly higher in high GCIR regions than in low GCIR regions in Costa Rica, despite the fact that no significant difference was found in the prevalence of H pylori infection between the regions, suggesting that the H pylori cagA gene was associated with the development of severe gastric injury, glandular atrophy and cancer, which probably influenced the GCIR variability in the country. However, further investigation is needed to demonstrate a significant association of H pylori and/or host factors with GCIR variability in Costa Rica.
The aim of this study was to evaluate whether host genetic factors such as interleukin (IL)-1&bgr; (-511 and +3954), IL-10 (-1082 and -592) and IL-1RN intron 2 variable number of tandem repeat (VNTR) polymorphisms in response to H pylori infection, and/or H pylori cagA, vacA and babA2 genotype distribution could be associated with the GCIR variability present in Costa Rica.
MATERIALS AND METHODS
The patients in this study attended a digestive center in San Jose, Costa Rica. Out of 402 continuous dyspeptic patients who underwent upper endoscopy from January to July 2005 and from January to July 2006, a total of 191 H pylori-positive patients (80 males, 111 females; age range 23-76 years) were enrolled for the determination of cytokine gene polymorphisms in IL-1&bgr;, IL-1RN and IL-10. Clinical isolates successfully obtained from both antrum and corpus specimens of 83 patients were eventually utilized for the PCR-based genotyping of the H pylori cagA, vacA and babA2 genes. Informed consent was obtained from each patient and the study was approved by the Ethics Committee of the institution.
In addition, gastric tissue specimens obtained from 52 consecutive H pylori-positive gastric cancer patients (GC group) who underwent surgical treatment at a hospital in Cartago, Costa Rica between February 2006 and March 2007, were utilized in this study to determine cytokine gene polymorphisms of the host, and were used for comparative purposes.
Based on a previous study, dyspeptic patients were classified into either high or low GCIR groups. Group A (high GCIR) was composed of patients belonging to regions with a GCIR in the range of 24.7-48.5/100000 persons, while in group B (low GCIR) the incidence rates ranged from 9.8-19.9/100000 persons. Patients belonging to regions with a GCIR of 20.0-24.6/100000 persons were removed from the study to further distinguish group A from group B. Information on age, gender, place of origin, symptoms and medication was collected. Patients with a recent intake of proton pump inhibitors, antibiotics, non-steroidal anti-inflammatory drugs, or any drug that could alter the state of the gastric mucosa were excluded from this study. Likewise, patients with H pylori eradication or previous attempted eradication therapy, previous gastric surgery as well as patients with Asian ancestry were also excluded from the study.
Endoscopic and histological evaluations
Endoscopy was performed with Olympus Evis Excera 160 and 180 videoendoscopes (Olympus America Inc., San Jose, CA, USA). From each patient, five biopsies (two from the antrum, two from the corpus and one from the cisura angularis) were collected for histological examination. Two more biopsies (one from the antrum and one from the corpus) were also taken to obtain the isolates following bacterial culture.
The five biopsy samples from each of the 191 patients were conventionally fixed in 100 mL/L aqueous formaldehyde, and embedded in paraffin. Serial 3- to 4-&mgr;m sections were stained with hematoxylin and eosin for histological observation. Each biopsy specimen was evaluated independently by two experienced pathologists blinded to the endoscopic and laboratory examinations. All discrepant diagnoses were re-examined by both pathologists together in order to reach a final consensus diagnosis. All five biopsies were examined for the presence of glandular atrophy and intestinal metaplasia and were scored into one of four grades (0: none, 1: mild, 2: moderate and 3: marked) for both the antrum and the body of the stomach, according to the updated Sydney System of classification and grading of gastritis. Gastric glandular atrophy was defined as the loss of gastric glands, and its replacement with fibrosis or metaplastic epithelium. Intestinal metaplasia was defined as the presence of foci where at least three neighboring gastric pits containing two or more goblet cells (in each pit) were visualized in any part of the stomach.
Determination of H pylori infection
H pylori infection was determined by either serum antibodies to H pylori, rapid urease test (RUT) or histological examinations of biopsy specimens obtained from the antrum, cisura angularis and body of the stomach. Patients were considered to be infected with the bacterium if either serum antibodies to H pylori were found, the biopsy specimen was positive for RUT or the bacterium was observed in any of the hematoxylin and eosin-stained sections.
Extraction of human DNA and genotyping of cytokine polymorphisms
Human DNA was extracted from biopsy specimens using a DNA extraction kit (QIAamp DNA mini kit; Qiagen K.K., Tokyo, Japan), according to the manufacturer’s instructions. Cytokine gene polymorphisms in IL-1&bgr; (-511 and +3954) and IL-10 (-1082 and -592) were examined by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analysis, as described previously and visualized by 50 mL/L ethidium bromide staining on 30 mL/L agarose gels. The IL-1RN variable number of tandem repeat (VNTR) polymorphism was detected by PCR and visualized on 20 mL/L agarose gels with alleles being classified conventionally according to El-Omar et al as follows: allele 1, four repeats; allele 2, two repeats; allele 3, five repeats; allele 4, three repeats and allele 5, six repeats. Because alleles 3, 4 and 5 were very rare, the alleles were classified into short (allele 2: *2) and long (alleles 1, 3, 4 and 5: L) alleles for statistical analysis, as described previously.
Isolation of H pylori from biopsy specimens and DNA extraction
The homogenized biopsy specimens were placed on H pylori selective agar plates (Helico VI agar, E-MS70, Eiken Chemical Co., Ltd., Japan) and cultured at 37ºC under microaerobic conditions (100 mL/L CO2) for five to seven days. The presence of H pylori colonies was confirmed by typical morphology, Gram staining and a positive urease test. From 83 patients, a total of 166 clinical isolates obtained from both antrum and corpus specimens were subjected to genomic DNA (gDNA) extraction using a DNA kit (Qiagen, Tokyo, Japan) according to the manufacturer’s instructions.
Detection of H pylori cagA, vacA and babA2 genes by PCR
The genomic DNAs were subjected to PCR for H pylori genotyping analysis. Genotyping of the cagA gene was examined using primer pairs D008 and R008, and cagA-Fnz3 and cagA-seqR1 (Table 1). The analysis of the vacA s and m regions was carried out as previously described. Genotyping of the babA2 gene was examined using reported primers and additional primers babA2-Fnc1 (5’-GAAAAAACATGAAAAAACACATCCTTT-CAT-3’) and babA2-Rmn2 (5’-TCTGGGTTAATGGCT-TGCC-3’) designed according to the following conditions: pre-heat for 2 min at 96°C, followed by 40 cycles at 96°C for 30 s, 49°C for 30 s, and 72°C for 1 min. All discrepant results of cagA and babA2 genotyping were confirmed by sequence analysis (Genetic Analyzer 3130 Applied Biosystems, Foster City, CA, USA) following PCR using a Big Dye Terminator v1.1 Cycle sequencing kit (Applied Biosystems, Foster City, CA, USA).
Table 1 PCR primers for amplification of cagA, vacA and babA2 genes.
Statistical analysis was performed using the Chi-square test and the Fisher’s exact probability test (STATA SE (version 8) statistical software). A P-value of < 0.05 was regarded as statistically significant. Multivariate analysis was performed by logistic regression (SPSS 13.0 Japanese version (SPSS Japan Inc., 2005) adjusting for gender and age. Odds ratios (OR) with 95% confidence intervals (CI) were used to study the influence of host and bacterial factors on the development of gastric cancer.
Comparison of gender and age of patients between groups A and B
Gender and age distribution in group A (101, 49 men, 52 women; mean ± SD, 50.42 ± 11.5 years) was not significantly different when compared with that in group B (90, 33 men, 57 women; mean ± SD, 50.87 ± 13.6 years) (P = 0.81 and P = 0.99, respectively; Table 2).
Table 2 Characteristics of H pylori-positive Costa Rican patients.
Number of patients
Mean age (yr, ± SD)
50.4 ± 11.5
50.9 ± 13.6
Gastric atrophy and intestinal metaplasia in groups A and B
The prevalence of gastric atrophy was higher in group A (35.6%, 36/101) than in group B (26.7%, 24/90), although the difference did not reach statistical significance (P = 0.12, Table 2). However, the prevalence of intestinal metaplasia was found to be significantly higher in group A (16.3%, 17/101) than in group B (6.7%, 6/90; P = 0.02).
Interleukin-1 and -10 polymorphisms in groups A and B
The analysis of cytokine gene polymorphisms including IL-1&bgr;-511 and +3954, IL-1RN intron 2, and IL-10-1082 and -592 did not reveal any significant difference between groups A and B (Table 3). However, when the role of cytokine polymorphisms on gastric cancer was evaluated, IL-1&bgr;+3954_T/C, IL-1RN*2/L, IL-10-592_A/A and IL-10-592_C/A were found to be individually associated with this cancer, irrespective of GCIR grouping (Table 3).
Table 3 Statistical analysis for several cytokine gene polymorphisms according to high gastric cancer incidence rate and gastric cancer in H pylori-positive Costa Rican patients.
OR (95% CI)
OR (95% CI)
Interleukin-1RN intron 2
-: Unable to compute. Pos: Positive; Neg: Negative.
Mixed strain infection of H pylori colonized in the stomach in clinical isolates obtained from the antrum and corpus
Mixed strain infection of H pylori has been defined as the colonization of the same patient by H pylori strains harboring more than one vacA genotype in the same stomach. The analysis of the H pylori vacA gene in terms of its presence/absence and genotype in each clinical isolate between the antrum and corpus in 83 patients, showed a mixed strain infection in only one patient belonging to group B and in six patients belonging to group A, of which five were diagnosed with either gastric atrophy or both gastric atrophy and intestinal metaplasia (Table 4). The cagA and babA2 genes were also examined according to the same terms in those 83 patients. The prevalence of cagA did not differ in any of the patients while the prevalence of babA2 differed in two patients without discordant vacA alleles, both belonging to group A.
Table 4 Patients with discordant H pylori vacA and babA2 genes from antrum and corpus biopsy specimens in the same stomach.
A (High GCIR)
AG + IM
AG + IMA
AG + IM
B (Low GCIR)
AG + IM
H pylori cagA, vacA and babA2 genes in clinical isolates from a non-mixed infection
In the 76 clinical isolates obtained from a non-mixed infection, the prevalence of cagA and the prevalence of vacA s1b in group A (both 87.8%) were found to be significantly higher than those in group B (65.7% and 68.6%, respectively) (Table 5). A tendency for an association between vacA m1 and GCIR variability was reported, while no significant difference was found in the prevalence of babA2 between the groups.
Table 5 Statistical analysis for the prevalence of H pylori genes or alleles in Costa Rican clinical isolates from groups A and B.
Group A (n = 41, %)
Group B (n = 35, %)
OR (95% CI)
Combination of cytokine polymorphisms and H pylori virulence factors in gastric cancer and non-gastric cancer patients
To investigate the influence of combined factors on the development of GC, we used the cytokine polymorphisms that were associated with GC in this study. The presence of a combination of IL-1&bgr;+3954_T/C, IL-1RN*2/L and IL-10-592_C/A slightly increased the risk of GC (adjusted OR 4.7, 1.7-13.0) when compared with patients carrying only one of the cytokine polymorphisms previously cited (Table 6). However, a combination of these polymorphisms with the addition of H pylori vacA s1b and m1 genotypes, which were chosen due to their association with GC reported in a previous Costa Rican study, considerably increased the risk of GC (adjusted OR 7.2, 1.4-36.4). The risk was further increased when a combination of only IL-1 polymorphisms (IL-1&bgr;+3954_T/C, and IL-1RN*2/L) and H pylori vacA s1b/m1 was evaluated (adjusted OR 9.8, 2.9-32.9).
Table 6 Adjusted odd ratios with 95% confidence intervals and P-value for combinations of host and bacterial factors according to gastric cancer in Costa Rican H pylori-positive patients.
The gastric cancer incidence rate in Costa Rica shows regional variation. Using H pylori-positive patients selected from high and low GCIR regions, the main objective of this study was to evaluate the potential impact of H pylori and/or host genetic factors on GCIR variability in Costa Rica.
The analysis of human genetic polymorphisms within the cytokine genes IL-1&bgr;, IL-1RN and IL-10 (Table 3) as well as the ABO blood group status (data not shown) did not show any significant differences between groups A and B (high and low GCIR groups, respectively) indicating that the genetic profile of the host, including these evaluated factors, did not seem to be linked to GCIR variability in Costa Rica. It has been reported that the presence of proinflammatory cytokines induces a hypochlorhydric and atrophic response to H pylori infection. In particular, IL-1&bgr; is important in initiating and amplifying the inflammatory response to H pylori infection, resulting in severe inflammation possibly leading to atrophic and metaplastic changes in the gastric mucosa. An association between cytokine polymorphisms in IL-1&bgr; and IL-1RN, and gastric premalignant lesions was previously reported in a Costa Rican population, while carriers of IL-1&bgr;+3954_T/C and IL-1RN*2/L had an increased risk for developing gastric cancer in another Costa Rican study. Likewise, our results showed that the prevalence of the proinflammatory genotypes IL-1&bgr;+3954_T/C and IL-1RN*2/L was significantly higher in gastric cancer cases than in non-cancer cases, supporting the association of polymorphisms within IL-1&bgr; and IL-1RN and gastric cancer in the Costa Rican population. Our results also showed that the carriage of IL-10-592_A/A or IL-10-592_C/A was also associated with an increased risk for gastric cancer, which has been reported previously. This is the first time that polymorphisms within the cytokine gene IL-10 have been associated with increased risk for gastric cancer in a Costa Rican population. Collectively, these studies thus suggest that in Costa Rica, the proinflammatory cytokine genetic profile of the host is involved in the development of gastric malignancy; but, it does not seem to play a main role in GCIR variability between regions.
The evaluation of H pylori virulence factors revealed that all H pylori strains detected in gastric atrophy and/or intestinal metaplasia cases were positive for cagA, vacA s1b and vacA m1, supporting the association of H pylori cagA and vacA genotype distribution with gastric cancer and premalignant lesions reported in a previous Costa Rican study. In addition, the prevalence of H pylori cagA and vacA s1b was significantly higher in the high GCIR group than in the low GCIR group, and a tendency for an association between vacA m1 and GCIR variation was also detected, confirming the association between H pylori virulence factors, specifically cagA, and the GCIR variability in Costa Rican regions suggested in a previous study. However, additional factors, especially not yet determined host and/or environmental and lifestyle factors could also be involved in GCIR variability in Costa Rica, as it seems unlikely that this phenomenon could be solely explained by the status of H pylori infection. The association between several cytokine polymorphisms and gastric cancer reported in this and past Costa Rican studies may support this possibility. Furthermore, this study also showed that carriers of IL-1&bgr;+3954_T/C, IL-1RN*2/L and IL-10-592_C/A and carriers of these polymorphisms together with the presence of H pylori vacA s1b/m1 increased the risk of gastric cancer when compared with patients not carrying any of these factors, suggesting that a synergistic effect of a combination of bacterial and host genotypes may determine the severity of the gastritis and the final outcome of H pylori infection. Such a suggestion has been documented in previous studies.
A comparative analysis of the status of the H pylori genes in each clinical isolate between antrum and corpus specimens demonstrated that a mixed strain infection (discordant vacA genes in the same stomach) was observed in six patients from the high GCIR group, but in only one patient from the low GCIR group. Likewise, the prevalence of gastric premalignant lesions, including gastric atrophy and intestinal metaplasia, was found more frequently in the high GCIR group than in the low GCIR group. The reason for the contrasting prevalence of mixed strain infection and premalignant lesions between high and low GCIR regions is still unknown. One may speculate that during persistent infection by H pylori due to yet undetermined factors associated with high population density areas such as urban lifestyle stress or inadequate intake of nutrients, subjects from high GCIR regions develop more severe gastric mucosal injury with atrophic and metaplastic changes, leading to a high genetic diversity of the bacterium for adaptation to this harsh gastric microenvironment. In fact, in strains isolated from Costa Rican patients, a high frequency of recombinated H pylori genes (ten of ten strains) has been reported. Alternatively, it does not exclude the possibility that the contrasting prevalence is caused by the difference in the frequency rate of superinfection by H pylori strains, which according to population density or yet undetermined factors, may occur more frequently in subjects from high GCIR regions, supposing a higher possibility of infection with the more virulent strains, which in fact have been linked with the development of gastric premalignant lesions. However, such development of premalignant changes and superinfection or genetic recombination within H pylori remains unclear as to which is cause and which is effect. Further investigation is essential to understand this issue, especially an investigation which includes an increased number of mixed strain infection-positive cases.
To summarize, our results demonstrated that although the carriage of proinflammatory IL-1&bgr;+3954_T/C, IL-1RN*2/L, IL-10-592_C/A and IL-10-592_A/A polymorphisms was associated with an increased risk for the development of gastric cancer, the characteristics of H pylori infection, in particular the status of cagA and vacA genotype distribution, seemed to play a major role in gastric cancer incidence rate variability in Costa Rican regions.
Costa Rica has one of the highest age-adjusted incidence and mortality rates for gastric cancer. Costa Rica has regions with contrasting gastric cancer incidence rates (GCIR). The cause of gastric cancer is thought to be multifactorial. The risk is high in subjects infected with Helicobacter pylori (H pylori) and even higher in those infected with strains co-expressing the cagA, vacA s1 and babA2 genes. Cytokine gene polymorphisms of the host, IL-1&bgr;, IL-1RN and IL-10, in response to H pylori infection, have also been associated with an increased risk for developing gastric cancer.
The research in this area is focused on the evaluation of host genetic factors such as interleukin (IL)-1&bgr; (-511 and +3954), IL-10 (-1082 and -592) and IL-1RN intron 2 variable number of tandem repeat (VNTR) polymorphisms in response to H pylori infection, and H pylori cagA, vacA and babA2 genotype distribution on the association with the GCIR variability in Costa Rica. A total of 191 H pylori-positive patients were enrolled for the determination of cytokine gene polymorphisms. Clinical isolates from gastric specimens of 83 patients were used for the PCR-based genotyping of the H pylori cagA, vacA and babA2 genes.
Innovations and breakthroughs
Cytokine polymorphisms showed no association with GCIR variability. However, gastric atrophy, intestinal metaplasia and strains with different vacA genotypes in the same stomach (mixed strain infection) were more frequently found in the high GC risk group than in the low GC risk group, and cagA and vacA s1b were significantly associated with high GCIR (P = 0.026 and 0.041, respectively). IL-1&bgr;+3954_T/C (OR 2.1, 1.0-4.3), IL-1RN*2/L (OR 3.5, 1.7-7.3) and IL-10-592_C/A (OR 3.2, 1.5-6.8) were individually associated with GC, and a combination of these cytokine polymorphisms with H pylori vacA s1b and m1 further increased the risk (OR 7.2, 1.4-36.4).
Although a proinflammatory cytokine genetic profile showed an increased risk for developing GC, the characteristics of H pylori infection, in particular the status of cagA and vacA genotype distribution seem to play a major role in GCIR variability in Costa Rica.
This study revealed that bacterial factors (i.e., cagA and vacA, but not babA2) are involved in regional differences in gastric cancer risk in Costa Rica, although host factors (IL-1B, IL-1RN and IL-10 polymorphisms) are associated individually with gastric cancer risk. There are interesting points found in this study in Costa Rica, where gastric risk and genetic distribution on H pylori are uniquely heterogeneous.
Peer reviewer: Shingo Tsuji, Professor, Department of Internal Medicine and Therapeutics, Osaka University Graduate School of Medicine(A8), 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan
Parkin DM, Bray FI, Devesa SS. Cancer burden in the year 2000. The global picture.Eur J Cancer. 2001;37 Suppl 8:S4-S66.
Kuroishi T, Hirose K, Takesaki T, Tomminaga S, Aoki K, Tajima K. Cancer mortality statistics in 30 countries (1953-1997).Cancer Mortality and Morbidity Statistics: Japan and the World-2004. Tokyo: Japan Scientific Societies Press; 2004;165-229.
Miranda M, Macaya J, Moya de Madrigal L. Aspectos epidemiológicos del cáncer gástrico en Costa Rica (in Spanish).Acta Med Costarric. 1997;20:207-214.
Mora D. Evolución de algunos aspectos epidemiológicos y ecológicos del cáncer gástrico en Costa Rica (in Spanish).Rev Costarric Salud Publica. 2003;21:7-17.
Sierra R, Barrantes R. [Ecological aspects of gastric cancer in Costa Rica].Rev Biol Trop. 1983;31:11-18.
Aird I, Bentall HH, Roberts JA. A relationship between cancer of stomach and the ABO blood groups.Br Med J. 1953;1:799-801.
Glober GA, Cantrell EG, Doll R, Peto R. Interaction between ABO and rhesus blood groups, the site of origin of gastric cancers, and the age and sex of the patient.Gut. 1971;12:570-573.
Eslick GD, Lim LL, Byles JE, Xia HH, Talley NJ. Association of Helicobacter pylori infection with gastric carcinoma: a meta-analysis.Am J Gastroenterol. 1999;94:2373-2379.
Huang JQ, Sridhar S, Chen Y, Hunt RH. Meta-analysis of the relationship between Helicobacter pylori seropositivity and gastric cancer.Gastroenterology. 1998;114:1169-1179.
Helicobacter and Cancer Collaborative Group. Gastric cancer and Helicobacter pylori: a combined analysis of 12 case control studies nested within prospective cohorts.Gut. 2001;49:347-353.
Danesh J. Helicobacter pylori infection and gastric cancer: systematic review of the epidemiological studies.Aliment Pharmacol Ther. 1999;13:851-856.
Basso D, Navaglia F, Brigato L, Piva MG, Toma A, Greco E, Di Mario F, Galeotti F, Roveroni G, Corsini A. Analysis of Helicobacter pylori vacA and cagA genotypes and serum antibody profile in benign and malignant gastroduodenal diseases.Gut. 1998;43:182-186.
Yamaoka Y, Kodama T, Gutierrez O, Kim JG, Kashima K, Graham DY. Relationship between Helicobacter pylori iceA, cagA, and vacA status and clinical outcome: studies in four different countries.J Clin Microbiol. 1999;37:2274-2279.
Zambon CF, Navaglia F, Basso D, Rugge M, Plebani M. Helicobacter pylori babA2, cagA, and s1 vacA genes work synergistically in causing intestinal metaplasia.J Clin Pathol. 2003;56:287-291.
Zambon CF, Basso D, Navaglia F, Germano G, Gallo N, Milazzo M, Greco E, Fogar P, Mazza S, Di Mario F. Helicobacter pylori virulence genes and host IL-1RN and IL-1beta genes interplay in favouring the development of peptic ulcer and intestinal metaplasia.Cytokine. 2002;18:242-251.
Hwang IR, Kodama T, Kikuchi S, Sakai K, Peterson LE, Graham DY, Yamaoka Y. Effect of interleukin 1 polymorphisms on gastric mucosal interleukin 1beta production in Helicobacter pylori infection.Gastroenterology. 2002;123:1793-1803.
Peek RM Jr, Blaser MJ. Helicobacter pylori and gastrointestinal tract adenocarcinomas.Nat Rev Cancer. 2002;2:28-37.
El-Omar EM, Carrington M, Chow WH, McColl KE, Bream JH, Young HA, Herrera J, Lissowska J, Yuan CC, Rothman N. Interleukin-1 polymorphisms associated with increased risk of gastric cancer.Nature. 2000;404:398-402.
Figueiredo C, Machado JC, Pharoah P, Seruca R, Sousa S, Carvalho R, Capelinha AF, Quint W, Caldas C, van Doorn LJ. Helicobacter pylori and interleukin 1 genotyping: an opportunity to identify high-risk individuals for gastric carcinoma.J Natl Cancer Inst. 2002;94:1680-1687.
Machado JC, Figueiredo C, Canedo P, Pharoah P, Carvalho R, Nabais S, Castro Alves C, Campos ML, Van Doorn LJ, Caldas C. A proinflammatory genetic profile increases the risk for chronic atrophic gastritis and gastric carcinoma.Gastroenterology. 2003;125:364-371.
El-Omar EM, Rabkin CS, Gammon MD, Vaughan TL, Risch HA, Schoenberg JB, Stanford JL, Mayne ST, Goedert J, Blot WJ. Increased risk of noncardia gastric cancer associated with proinflammatory cytokine gene polymorphisms.Gastroenterology. 2003;124:1193-1201.
Akopyanz N, Bukanov NO, Westblom TU, Kresovich S, Berg DE. DNA diversity among clinical isolates of Helicobacter pylori detected by PCR-based RAPD fingerprinting.Nucleic Acids Res. 1992;20:5137-5142.
Marshall DG, Coleman DC, Sullivan DJ, Xia H, O’Morain CA, Smyth CJ. Genomic DNA fingerprinting of clinical isolates of Helicobacter pylori using short oligonucleotide probes containing repetitive sequences.J Appl Bacteriol. 1996;81:509-517.
Con SA, Valeren AL, Takeuchi H, Con-Wong R, Con-Chin VG, Con-Chin GR, Yagi-Chaves SN, Mena F, Brenes Pino F, Echandi G. Helicobacter pylori CagA status associated with gastric cancer incidence rate variability in Costa Rican regions.J Gastroenterol. 2006;41:632-637.
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.
Shih CM, Lee YL, Chiou HL, Hsu WF, Chen WE, Chou MC, Lin LY. The involvement of genetic polymorphism of IL-10 promoter in non-small cell lung cancer.Lung Cancer. 2005;50:291-297.
Zeng ZR, Hu PJ, Hu S, Pang RP, Chen MH, Ng M, Sung JJ. Association of interleukin 1B gene polymorphism and gastric cancers in high and low prevalence regions in China.Gut. 2003;52:1684-1689.
Covacci A, Censini S, Bugnoli M, Petracca R, Burroni D, Macchia G, Massone A, Papini E, Xiang Z, Figura N. Molecular characterization of the 128-kDa immunodominant antigen of Helicobacter pylori associated with cytotoxicity and duodenal ulcer.Proc Natl Acad Sci USA. 1993;90:5791-5795.
Con SA, Takeuchi H, Valerin AL, Con-Wong R, Con-Chin GR, Con-Chin VG, Nishioka M, Mena F, Brenes F, Yasuda N. Diversity of Helicobacter pylori cagA and vacA genes in Costa Rica: its relationship with atrophic gastritis and gastric cancer.Helicobacter. 2007;12:547-552.
Atherton JC, Cao P, Peek RM Jr, Tummuru MK, Blaser MJ, Cover TL. Mosaicism in vacuolating cytotoxin alleles of Helicobacter pylori. Association of specific vacA types with cytotoxin production and peptic ulceration.J Biol Chem. 1995;270:17771-17777.
Gerhard M, Lehn N, Neumayer N, Boren T, Rad R, Schepp W, Miehlke S, Classen M, Prinz C. Clinical relevance of the Helicobacter pylori gene for blood-group antigen-binding adhesin.Proc Natl Acad Sci USA. 1999;96:12778-12783.
Ashour AA, Magalhaes PP, Mendes EN, Collares GB, de Gusmao VR, Queiroz DM, Nogueira AM, Rocha GA, de Oliveira CA. Distribution of vacA genotypes in Helicobacter pylori strains isolated from Brazilian adult patients with gastritis, duodenal ulcer or gastric carcinoma.FEMS Immunol Med Microbiol. 2002;33:173-178.
Con SA, Con-Wong R, Con-Chin GR, Con-Chin VG, Takeuchi H, Valeren AL, Echandi G, Mena F, Brenes F, Yasuda N. Serum pepsinogen levels, Helicobacter pylori CagA Status, and cytokine gene polymorphisms associated with gastric premalignant lesions in Costa Rica.Cancer Epidemiol Biomarkers Prev. 2007;16:2631-2636.
Alpizar-Alpizar W, Perez-Perez GI, Une C, Cuenca P, Sierra R. Association of interleukin-1B and interleukin-1RN polymorphisms with gastric cancer in a high-risk population of Costa Rica.Clin Exp Med. 2005;5:169-176.
Kauser F, Khan AA, Hussain MA, Carroll IM, Ahmad N, Tiwari S, Shouche Y, Das B, Alam M, Ali SM. The cag pathogenicity island of Helicobacter pylori is disrupted in the majority of patient isolates from different human populations.J Clin Microbiol. 2004;42:5302-5308.