Association of the interleukin-1 beta genetic polymorphism and gastric cancer risk in Japanese

Interleukin-1B (IL-1B) polymorphisms and gastric mucosal levels of IL-1beta cytokine in Korean patients with gastric cancer

Interleukin-1B and IL-1 receptor antagonist gene polymorphisms are associated with an increased risk of gastric cancer (GC) in Caucasian populations. However, recent studies could not find any association between IL-1B-511T polymorphism and the risk of GC in Asians. We tested for an association between IL-1 loci polymorphisms with increased gastric mucosal levels of IL-1beta and an increased risk of developing GC in a Korean population. Polymorphisms of IL-1A-889, IL-1B-31, IL-1B-511 and IL-1RN were genotyped in 434 controls and 234 patients with GC. Mucosal IL-1beta cytokine was measured using an ELISA. The frequencies of IL-1A, IL-1B-511, IL-1B-31 and IL-1RN were not statistically different between controls and all patients with GC. After subclassification of GC, only patients with intestinal-type GC showed a higher frequency of IL-1B-31T homozygotes (OR = 2.2; 95% CI = 1.1-4.3) compared with controls. Risk was also significantly increased in these patients for IL-1B-31T homozygotes compared with patients with diffuse-type GC (OR = 3.4; 95% CI = 1.5-7.7). As in Caucasian populations, linkage disequilibrium between IL-1B-31 and IL-1B-511 was nearly complete, but the pattern of haplotype related to the risk of GC (IL-1B-31T/IL-1B-511C) was opposite (IL-1B-511T/IL-1B-31C). Mucosal IL-1beta levels in H. pylori-infected GC patients were higher in patients homozygous for IL-1B-31T compared with IL-1B-31C/T and IL-1B-31C/C. Thus, the combined effects of H. pylori infection and IL-1B-31T/IL-1B-511C polymorphisms with enhanced mucosal IL-1beta production contributed to the development of intestinal-type GC in this Korean population.

Interleukin-4 gene intron-3 polymorphism is associated with transitional cell carcinoma of the urinary bladder

OBJECTIVE

To evaluate whether polymorphism of the interleukin-4 gene exon 3, and of the interleukin-1beta gene exon 5 and promoter region, are associated with transitional cell carcinoma (TCC) of the urinary bladder, as cytokines are hypothesized to be important in cancer formation.

PATIENTS, SUBJECTS AND METHODS

The study included 138 patients with TCC of urinary bladder and 105 healthy controls living in the same area. Each genetic polymorphism was typed using polymerase chain reaction-based restriction analysis. Genotype distribution and allelic frequencies between patients and controls were compared.

RESULTS

There were significant differences in genotype and allelic distribution of intron 3 RP1/RP2 polymorphism (P < 0.001), but no significant difference in genotype distribution or allelic frequencies of the interleukin-1beta gene polymorphism between patients with bladder cancer and controls.

CONCLUSION

The interleukin-4 gene intron 3 polymorphism is associated with bladder cancer and is a potential genetic marker in screening for the possible causes of bladder cancer.

Increased risk of intestinal type of gastric adenocarcinoma in Japanese women associated with long forms of CCTTT pentanucleotide repeat in the inducible nitric oxide synthase promoter

Tandem repeat number polymorphism of a CCTTT pentanucleotide in the promoter region of the inducible nitric oxide synthase gene (iNOS) and a polymorphism of the interleukin-1beta (IL-1B) promoter at position -31 were analyzed in DNA samples from 181 Japanese control subjects and 158 gastric cancer patients, including 96 intestinal type and 62 diffuse type. An association between the intestinal type of gastric adenocarcinoma and higher promoter activity of the iNOS gene was found in women, especially those having higher promoter activity of the IL-1B gene and without a history of smoking. Our results imply that chronic inflammation caused by excess nitric oxide generated by iNOS contributes to Helicobacter pylori-induced gastric cancer.

Association of polymorphism of IL-10 and TNF-A genes with gastric cancer in Korea

We performed this study to determine the role of polymorphisms of the IL-10 and TNF-alpha promoter genes in the carcinogenesis/pathogenesis of gastric cancer (GC) and peptic ulcer diseases (PUD) in Korea. A total of 232 patients with gastric diseases and 120 healthy controls were included. Polymorphisms of IL-10-1082/-592 gene and TNF-A-308 gene were genotyped by PCR-RFLP. There were no differences in genotypes and allele frequencies of IL-10 and TNF-A polymorphism between study group with GC or PUD and control group. In addition, there were no differences in genotypic frequencies according to H. pylori infection status, location of GC, and histologic type of GC. In conclusion, IL-10-1082/-592 and TNF-A-308 genetic polymorphisms may not be the important contributors to GC in Korea.

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

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.

Interleukin-1B gene promoter variants are associated with an increased risk of gastric cancer in a Chinese population

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.

Cytokine gene polymorphisms in Taiwan

Cytokine gene polymorphisms may affect their transcription, influence their level of production, and may be implicated in inducing susceptibility or resistance to diseases. Cytokine single-nucleotide polymorphisms (SNPs) were used to determine allelic and genotypic frequencies in the Minnan, the Hakka, and in four indigenous tribes: the Ami, the Tsou, the Atayal, and the Tao (or Yami). The following cytokine gene polymorphisms were analyzed: interleukin-1alpha (IL-1alpha) (T/C -889), IL-1beta (C/T -511, T/C +3962), IL-1R (C/T Pst-I 1970), IL-1Ralpha (T/C Mspa1-I 1100), IL-2 (T/G -330, G/T +166), IL-4 (T/G -1098, T/C -590, T/C -33), IL-4Ralpha (G/A +1902), IL-6 (G/C -174, G/A nt565), IL-10 (G/A -1082, C/T -819, C/A -592), IL-12 (C/A -1188), interferon-gamma (A/T UTR 5644), transforming growth factor-beta (C/T codon 10, G/C codon 25), and TNF-alpha (G/A -308, G/A -238). Little differences were observed between the Minnan and the Hakka. On the other hand, the Minnan and Hakka showed significant differences with the indigenous people.

Association between polymorphisms of interleukin-1B and interleukin-1 receptor antagonist genes and host susceptibility to gastric cancer

AIM: To explore the genotype frequencies of polymorphisms in the interleukin-1B (IL-1B) gene promoter region -31, -511 and +3 954 loci and interleukin-1 receptor antagonist gene (IL-1RN) variable number of tandem repeat (VNTR) in gastric cancer cases and cancer-free controls in a Chinese population, and to evaluate the association between polymorphisms of IL-1B and IL-1RN genes and host susceptibility to gastric cancer.

METHODS: Genotypes were determined by a modified PCR-restriction fragment length polymorphism (PCR-RFLP) approach in 285 histologically-confirmed gastric cancer patients and 265 age-, sex- and residence area frequency-matched cancer-free controls in a Chinese population.

RESULTS: The genotype frequencies of IL-1B C-31T polymorphism were 21.8% for CC, 48.6% for CT and 29.6% for TT among gastric cancer patients, and 27.9%, 48.8% and 23.3% among control subjects (P = 0.203). Similarly, the genotype frequencies of IL-1B T-511C polymorphisms were 18.2% for TT, 56.5% for CT, 25.3% for CC among patients and 24.9%, 52.5%, 22.3% among controls (P = 0.184). Multivariate logistic regression analyses revealed that the risks associated with the IL-1B variant genotypes were 1.75 (95%CI = 1.08-2.85) for -31TT and 1.63 (95%CI = 0.98-2.73) for -511CC, respectively, compared with their wild-type homozygotes. Furthermore, we found a greater increased risk in individuals with both H. pylori nfection and the variant genotypes (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-1β. No significant association was observed between polymorphisms of IL-1RN gene and IL-1B gene +3 954 locus and gastric cancer risk.

CONCLUSION: The two IL-1B polymorphisms within promoter region may contribute to the risk of developing gastric cancer in our Chinese population, especially in individuals with H. pylori nfection.

Polymorphisms of Interleukin-1beta and beta3-Adrenergic Receptor in Japanese Patients With Nonalcoholic Steatohepatitis

BACKGROUND

Obesity, hypertriglyceridemia, and diabetes have been reported as frequent complications observed in patients with nonalcoholic steatohepatitis (NASH) in Western countries. The aim of this study was to investigate the genetic predisposition on NASH pathogenesis in the Japanese population.

METHODS

Genotypes of two previously described functional polymorphisms-beta3-adrenergic receptor 190 T/A polymorphism, which results in Trp64Arg (W64R) amino acid replacement, and interleukin-1beta-511 T/C polymorphism in the promoter sequence-were determined in 63 Japanese NASH patients and 100 healthy volunteers using polymerase chain reaction and restriction fragment length polymorphism.

RESULTS

beta3-adrenergic receptor R allele frequency and the R/- (W/R and R/R) genotype frequency were significantly higher in NASH patients than those in control subjects. Interleukin-1beta-511 T allele frequency and the T/T genotype frequency were significantly higher in NASH patients than those in control subjects. Obesity, hypertriglyceridemia, and hyperinsulinemia were associated with NASH patients with the R/- genotype, whereas an increase in fasting plasma glucose level and a decrease in insulinogenic index were associated with NASH patients with the W/W genotype.

CONCLUSION

This study confirmed the contribution of obesity, glucose intolerance, and hypertriglyceridemia to NASH development in the Japanese population. In addition to these factors, genetic predispositions to obesity and inflammation in the Japanese population were shown to contribute much to the development of NASH.

Risks of interleukin-1 genetic polymorphisms and Helicobacter pylori infection in the development of gastric cancer

BACKGROUND

The host genetic factors that determine the clinical outcomes of Helicobacter pylori-infected individuals remain unclear.

AIM

To elucidate the risks of host interleukin-1 (IL-1) genetic polymorphisms and H. pylori infection in the development of gastric cancer.

METHODS

In a case-control study of 164 controls and 142 patients with gastric cancer, the IL-1B-511 biallelic polymorphisms and the IL-1RN penta-allelic variable number of tandem repeats were genotyped.

RESULTS

The carriage of IL-1RN*2, male gender, old age and H. pylori infection independently increased the risk of gastric cancer, with odds ratios of 3.3 [95% confidence interval (CI), 1.4-7.7], 2.1 (95% CI, 1.2-3.8), 5.3 (95% CI, 3.1-9.0) and 2.2 (95% CI, 1.3-3.8), respectively. H. pylori-infected individuals who were carriers of IL-1RN*2 showed increased risks of both intestinal and diffuse types of gastric cancer, with odds ratios of 11.0 and 8.7, respectively. In addition, these individuals also had a higher score of intestinal metaplasia in the corpus than did uninfected non-carriers.

CONCLUSIONS

This study is the first to verify IL-1RN*2 as an independent factor governing the development of gastric cancer in Asian individuals. A combination of H. pylori testing and host genotyping may target the eradication of H. pylori to high-risk individuals.

Promoter polymorphisms of tumor necrosis factor-alpha are associated with risk of gastric mucosa-associated lymphoid tissue lymphoma

Genes involved in regulating antimicrobial immunity and inflammation may modulate the risk of Helicobacter pylori-associated diseases. IL-1 and TNF-alpha are major cytokines detected in H. pylori-infected tissues. We aimed to determine the role of gene polymorphisms for these cytokines and their receptors in 2 distinct H. pylori-related gastric malignancies, adenocarcinoma (GAC) and maltoma. Genotyping for IL-1beta (-31 C/T, -511 C/T), TNF-alpha (-238 G/A, -308 G/A, -857 C/T, -863 C/A, -1031 T/C), TNFR1 (-383 A/C) and TNFR2 (196 G/T) was undertaken for 70 patients with maltoma and 204 patients with noncardia GAC and compared to 210 unrelated healthy controls. Genotype frequencies showed no differences among patients with GAC or maltoma and controls for IL-1beta, TNFR1 or TNFR2. The TNF-alpha -857 T variant was significantly underrepresented in maltoma compared to controls (6.4% vs. 14.3%, p = 0.018), conferring a 3-fold decrease in risk (OR = 0.33, 95% CI 0.15-0.75). Comparison of allele frequencies between GAC and controls failed to show any statistical significance for TNF-alpha polymorphisms. We concluded that TNF-alpha -857 T itself or a neighboring gene may modify the risk of maltoma. The differences in genetic background as well as divergent clinicopathologic features between GAC and maltoma support the notion that fundamental mechanistic differences exist in these 2 well-defined H. pylori-related malignancies.

Association of interleukin 1B gene polymorphism and gastric cancers in high and low prevalence regions in China

AIM

Our aim was to study the relationship between interleukin 1B (IL-1B) polymorphism, Helicobacter pylori infection, and gastric cancer in high prevalent (Shanxi) and low prevalent (Guangdong) regions in China.

METHOD

Genomic DNA was extracted from peripheral blood of 192 healthy volunteers, 84 gastric cancer patients from Guangdong and 169 healthy volunteers, and 86 gastric cancer patients from Shanxi. Polymorphisms in IL-1B that encodes IL-1beta and IL-1RN that encodes IL-1 receptor antagonist were analysed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). These polymorphic sites include promoter regions of IL-1B at positions +3954, -511 (C-T transition), and -31 (T-C transition), and IL-1RN variable tandem repeats.

RESULTS

In the low prevalence region, the frequencies of the IL-1B +3954 T/T and IL-1RN *2/*2 genotypes were similar. IL-1B -511T/T genotype frequency was significantly higher among patients with gastric cancer (25.0%) than control subjects (12.5%) (chi2=6.7, p=0.01). In the high prevalence region, the frequencies of the IL-1B +3954T/T and -511T/T genotypes and the IL-1RN *2/*2 genotype in the cancer and control groups were similar. IL-1B -31C/C genotype frequency was significantly higher among patients with gastric cancer (90.0%) than controls (78.0%) (chi2=5.0, p=0.025). Compared with the low prevalence region, control subjects from the high prevalence region had a higher frequency of the IL-1B -511T/T genotype (23.0% v 12.5%; chi2=7.0, p<0.008). While H pylori infection alone had only a modest effect on the risk of gastric cancer development (odds ratio (OR) 5.0 (95% confidence interval (CI) 1.5-16.3)), combined with the IL-1B -511T/T genotype the risk was markedly elevated (OR 17.1, 95% CI 3.8-76.4).

CONCLUSION

IL-1B -511T/T genotypes are associated with gastric cancer in China. The effect of IL-1B polymorphism is less obvious in areas of high prevalence for gastric cancer.

Interleukin-1beta genetic polymorphism influences the effect of cytochrome P 2C19 genotype on the cure rate of 1-week triple therapy for Helicobacter pylori infection

OBJECTIVES

Genetic polymorphism of interleukin (IL)-1beta is associated with differences in gastric acid suppression in response to Helicobacter pylori (H. pylori) infection. Thus, the polymorphism might affect H. pylori eradication therapy, as antibiotics used in treatment regimens may be acid sensitive. In this study, we examined the impact of IL-1beta genetic polymorphism on the cure rate of triple therapy for H. pylori in relation to cytochrome P (CYP) 2C19 genotype and antibiotic resistance.

METHODS

A total 249 patients with peptic ulcer disease were randomized to receive one of the following regimens: amoxicillin and clarithromycin together with omeprazole, lansoprazole, or rabeprazole. CYP2C19 and IL-1beta-511 genetic polymorphisms were analyzed by polymerase chain reaction-restriction fragment length polymorphism.

RESULTS

The intention-to-treat-based overall cure rate was 74.3% (95% CI=68-79%). In the normal acid secretion IL-1beta genotype group, the cure rate among CYP2C19 poor metabolizers (93.3%, 95% CI=56-99%) was significantly higher than among subjects in the CYP2C19 homozygous (60.0%, 95% CI=38-78%) and heterozygous (63.6%, 95% CI=46-78%), i.e., extensive metabolizer, groups (p<0.05). In the low acid secretion IL-1beta genotype group, there was no difference in the cure rate among the CYP2C19 genotype groups. Multiple logistic regression analysis identified susceptibility to clarithromycin (p<0.0001) and CYP2C19 genotype status (p=0.03) as significant independent factors for treatment failure.

CONCLUSION

IL-1beta genetic polymorphism, although not an independent factor in treatment outcome, influences the impact of the CYP2C19 genotype on the cure rate of 1-wk triple therapy for H. pylori infection.

Review article: clinical significance of mucosal-protective agents: acid, inflammation, carcinogenesis and rebamipide

While a great deal of clinical evidence has been found regarding anti-acids for the treatment of gastric disorders including peptic ulcers, not all disorders can be explained only by the hyperfunction of acid secretion. Especially in the Asian region, glandular atrophy is more prominent than in Western countries, therefore low acid output is often observed in these patients. Improvement of mucosal protection is rational therapy for these patients; this is the reason for use of these agents in Asian countries. Rebamipide has many biological activities for gastric mucosa such as increasing the blood flow and biosynthesis prostaglandins and the decrease of oxygen radicals. These suggest the possible efficacy of rebamipide in the prevention of both Helicobacter pylori-related and nonsteroidal anti-inflammatory drug (NSAID)-induced gastric injury, which has been proved by human studies. Rebamipide is the only mucosal-protective drug which can improve the histological gastritis in vivo, whereas anti-acids have a lesser effect in influencing gastritis. Improvement of gastritis is expressed not only in quantity but also in quality of gastritis, which is shown as the reduction of iNOS expression in the gastric mucosa. Clinically, it is suggested that rebamipide has the potential to prevent gastric carcinogenesis by improvement of histological gastritis.

Interleukin-10 genotypes associate with the risk of gastric carcinoma in Taiwanese Chinese

The association of cytokine genotypes with gastric carcinoma (GC) may be influenced by environmental factors and varies among different populations. Few studies have addressed the impact of different cytokine genotypes on the development and progression of GC. We analyzed 11 functional polymorphisms in tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-1, IL-4 and IL-10 genes in 220 Taiwanese Chinese with GC and in 230 healthy controls. The risk of genotypes was adjusted with confounding environmental risks. Our results revealed that the frequency of Helicobacter pylori infection [odds ratio (OR) 1.7, 95% confidence interval (CI) 1.19-2.56], cigarette smoking (OR 2.02, 95% CI 1.38-2.95) and high IL-10 producer genotype (OR 2.67, 95% CI 1.29-5.50) was significantly increased in the entire GC patients. Among different subtypes of GC, a higher risk of developing diffuse type (OR 1.64, 95% CI 1.01-2.67) or cardia cancer (OR 2.44, 95% CI 1.13-2.67) was observed for the CT/CC genotype of IL-4 at the position -590, whereas the high IL-10 producer genotype was significantly linked with the risk of cardia cancer (OR 3.21, 95% CI 1.06-9.73) or advanced stage (OR 2.29, 95% CI 1.12-4.64). No association was noted between GC and controls in the distribution of IL-1 and TNF-alpha genotypes. Logistic regression analyses revealed that H. pylori infection (OR 1.7, 95% CI 1.14-2.52), cigarette smoking (OR 1.87, 95% CI 1.27--2.96) and IL-10 genotype (OR 2.54, 95% CI 1.24-5.61) are independent risks for GC. Independent effects of IL-10 genotype, H. pylori infection and cigarette smoking indicate that carcinogenesis of GC is influenced by a variety of host and environmental factors.

Lack of association between pro-inflammatory genotypes of the interleukin-1 (IL-1B -31 C/+ and IL-1RN *2/*2) and gastric cancer/duodenal ulcer in Korean population

IL-1beta is a pro-inflammatory cytokine with multiple biological effects and is a potent inhibitor of gastric acid secretion, and IL-1RN has been shown to be associated with enhanced IL-1beta production in vitro. Recently, it was reported that the pro-inflammatory genotypes, IL-1B -31 C/+ and IL-1RN *2/*2, were associated with an increased risk of gastric cancer in a Caucasian population. We tested the association between the polymorphisms and 190 gastric cancer, 117 duodenal ulcer, and 172 healthy subjects as controls in the Korean population. The allele frequency of IL-1B -31 C was more prevalent in Korean (51%) than in Caucasian (30%), while the frequency of IL-1RN *2 allele was less in Korean (6%) than in Caucasian (27%). Using the IL-1B TT genotype as a reference group, the CC genotype was not associated with an increased risk of gastric cancer or duodenal ulcer in the Korean population (odds ratios (OR)=0.90, 95% confidence interval (CI)=0.50-1.64; OR=0.72, 95% CI=0.36-1.46, respectively). Similarly, IL-1RN*2 was not a risk genotype for either gastric cancer or duodenal ulcer. No association was recognized on the haplotype analysis of the two genes, either. Our results did not support the previous report that IL-1B -31 C/IL-1RN*2 polymorphisms were associated with an increased risk of gastric cancer. The lack of association with duodenal ulcer also suggested that the polymorphisms were not directly related to the acid-secreting capability.

Helicobacter pylori: resurrection of the cancer link

Helicobacter pylori is one of the most common pathogenic bacterial infections, colonizing an estimated half of all humans. In a subset of individuals, the infection leads to serious gastroduodenal disease such as peptic ulcers and gastric adenocarcinoma. The factors contributing to skewing this, in most cases benign, relationship into disease development are largely unknown. However, factors emanating from the bacterium, host and the environment have been shown to affect the risk for disease, although no factor can be singled out to be most important. The known factors are associated with affecting the risk of disease, and are not absolute. Virulence of H. pylori is affected by the existence and regulation of certain genes present in the bacterial population in a stomach. The effects of H. pylori on gastric cancer development have been challenged and the risk associated with infection with virulent (i.e. Cag PAI positive) H. pylori has likely been underestimated.

Effect of interleukin 1 polymorphisms on gastric mucosal interleukin 1beta production in Helicobacter pylori infection

BACKGROUND & AIMS

Although epidemiological studies suggest that interleukin (IL)-1 genetic polymorphisms are involved in Helicobacter pylori-related gastric carcinogenesis, the data are conflicting regarding the effects of these polymorphisms on IL-1beta production.

METHODS

IL-1B-511 polymorphism was genotyped by polymerase chain reaction (PCR)-restriction fragment length polymorphism, and IL-1RN variable number of tandem repeats was determined by PCR. Mucosal IL-1beta levels were measured by enzyme-linked immunosorbent assay. To determine which factors influence mucosal IL-1beta levels, gastric inflammation, and atrophy, multiple regression analyses were performed.

RESULTS

We studied 117 H. pylori-infected Japanese patients. Carriers of the IL-1B-511T/T genotype or IL-1RN*2 allele had higher mucosal IL-1beta levels than noncarriers (partial regression coefficient [PRC] +/- SE), TT versus CC: 37.6 +/- 6 [antrum] and 32.1 +/- 6 [corpus] pg/mg protein (P < 0.001 for each), *1/*2 versus *1/*1: 24 +/- 8 [antrum] (P <0.01) and 36.5 +/- 7 [corpus] (P <0.001). Simultaneous carriers of IL-1B-511T/T genotype and IL-1RN*2 allele had the highest IL-1beta levels (82.9 +/- 12 [antrum] and 87.2 +/- 11 [corpus]) and showed a synergistic effect between 2 loci. The *1/*2 carriers were closely related to atrophy (PRC +/- SE; 0.87 +/- 0.4 [antrum] and 0.93 +/- 0.4 [corpus], P < 0.05), whereas being a carrier of the -511T/T genotype was related to severe gastric inflammation.

CONCLUSIONS

IL-1 genetic polymorphisms influenced H. pylori-related gastric mucosal IL-1beta levels and were related to gastric inflammation and atrophy, factors thought to be important in gastric carcinogenesis.

Helicobacter pylori and gastric malignancies

The epidemiological link of Helicobacter pylori and gastric carcinoma was confirmed and the reported rate of gastric carcinoma development in the Japanese population with H. pylori gastritis was 2.9% during a 7.8-year period. Studies showed that gastric atrophy and intestinal metaplasia may partially regress after H. pylori eradication, but whether this will result in a decrease in the development of malignant lesions remains to be confirmed in large studies. Little progress was made towards the identification of criteria applicable to individualized populations that would benefit from H. pylori screening and surveillance of gastric malignancy. Studies of low-grade MALT lymphoma reported clinical and molecular features that may be useful to identify cases that may be responsive to H. pylori eradication therapy, namely evaluation of lymphoma stage by EUS and t(11;18). The role of H. pylori eradication therapy in high-grade MALT lymphoma needs to be evaluated in larger prospective studies. The application of methods of global analysis of gene expression (microarray studies) resulted in the explosion of information on the molecular pathways activated by H. pylori in gastric epithelial cells. New pathways that may play an important role in H. pylori carcinogenesis have been discovered in several studies.