this study was conducted during 14 months ( october 2014 to november 2015 ) on patients with ag ( n=39 ) and gc ( n=40 ) at two medical oncology and gastroenterology facilities in the northwestern region of algeria . infection with h. pylori was confirmed by histopathology of biopsies sampled during diagnostic endoscopy ( at least four biopsies of the antrum and body gastric mucosa should be available for each case ) and anti - hp igg serum antibody tests . the corresponding tissue sections were stained for slide reading in the anatomopathology department of the university hospital of sidi - bel - abbes , algeria . the existence of h. pylori dna in gastric biopsies and buccal swabs were analyzed by pcr amplification of the urec gene using primers as described by lage et al . ( 16 ) ( forward : 5-aagcttttaggggtgttaggggttt-3 and reverse : 5-aagcttactttctaacactaacgc-3 ) at a hybridization temperature of 55c . we employed a dna volume of 25 l according to pcr criteria , as described below . the amplified fragments were visualized by using the gelred nucleic acid gel stain , 10,000 x ( biotium , hayward , ca , usa ) , and 2.5% agarose gel . information about personal data , sociodemographic characteristics , educational level , blood type , rhesus factor , eating habits , smoking , and alcohol consumption were evaluated using a predetermined questionnaire . furthermore , all participants gave their consent after the study protocol had been explained to them . 387 ( article 25 ) dated 31 july 2006 about ethical trials in algeria , we obtained the required access authorizations to the concerned health facilities in order to accomplish our study protocol . furthermore , we obtained informed written consent from all participants and their treating physicians after the study protocol had been explained to them . il-1-31 and il-1-511 polymorphisms are single nucleotide changes in the promoter region , while the il-1rn polymorphism is a repetition of 86 bp in the second intron . the dna was extracted from 200 l whole blood samples , 20 mg of fresh gastric biopsy , or buccal swab in h. pylori transport medium using an extraction kit ( magazorbe genomic dna , promega , fitchburg , wisconsin , usa ) stored at 20c . genotyping of the two polymorphisms ( il-1-31 and il-1-511 ) was performed using the restriction fragment length polymorphism method ( pcr - rflp ) ( table 1 ) ( 6 , 10 ) . briefly , 2550 ng of dna was used in a volume of 25 l with 150 mm dntp , 6.25 pmol of each primer , 1 u of dna polymerase gotaq g2 hot start polymerase ( promega , fitchburg , wisconsin , usa ) , 5% dmso , 4 mm mgcl2 , and 5 l of 5x pcr buffer gotaq . the amplified / digested fragments were visualized with the gelred nucleic acid gel stain , 10,000 x ( biotium , hayward , ca , usa ) in 2.5% agarose gel . primers and conditions for analysis of the il-1 and il-1rn polymorphisms tm : melting temperature ; il-1-31 : cluster of gene encoding interleukin-1 in the promoter region of tata box at the 31 position ; il-1-511 : cluster of gene encoding interleukin-1 in the promoter region of tata box at the 511 position ; il-1rn : gene encoding the anti - inflammatory antagonist ( interleukin-1ra ) . variable numbers of tandem repeats ( vntr ) analysis in the second intron of the il-1rn gene was carried out by pcr . the different alleles were identified by the size of the pcr fragments and encoded in a conventional manner ( 6 , 13 ) as follows : allele 1 ( four repetitions ) , allele 2 ( two repetitions ) , allele 3 ( five repetitions ) , allele 4 ( three repetitions ) , and allele 5 ( six repetitions ) . according to previous studies ( 6 , 13 ) , as described in table 1 , the il-1rn alleles were dichotomized into two categories : long genotype ( l:>three repetitions ; alleles 1 , 3 , 4 , 5 ) and short genotype ( 2 : two repetitions ; allele 2 ) . data were processed and analyzed using spss 22.0 ( statistical package for the social sciences , ibm corporation ; chicago , il , august 2013 ) . chi - square test was used to evaluate differences in the distribution of polymorphisms between different groups . all allelic distributions were examined for the corresponding differences of their hardy - weinberg equilibrium . the relative risk was evaluated by multivariate logistic regression based on categorical reference predictor models , adjusting for sex and age with a confidence interval ( ci ) of 95% and statistical significance set at p<0.05 . allelic combinations of models of the three variants closely related polymorphisms of il-1 and il-1rn were analyzed . the study of the haplotypes and linkage disequilibrium between loci ( estimated by r 
  and d ) was carried out via the web interface in the linkdos ( www.genepop.curtin.edu.au/linkc.html ) . this study was conducted during 14 months ( october 2014 to november 2015 ) on patients with ag ( n=39 ) and gc ( n=40 ) at two medical oncology and gastroenterology facilities in the northwestern region of algeria . infection with h. pylori was confirmed by histopathology of biopsies sampled during diagnostic endoscopy ( at least four biopsies of the antrum and body gastric mucosa should be available for each case ) and anti - hp igg serum antibody tests . the corresponding tissue sections were stained for slide reading in the anatomopathology department of the university hospital of sidi - bel - abbes , algeria . the existence of h. pylori dna in gastric biopsies and buccal swabs were analyzed by pcr amplification of the urec gene using primers as described by lage et al . ( 16 ) ( forward : 5-aagcttttaggggtgttaggggttt-3 and reverse : 5-aagcttactttctaacactaacgc-3 ) at a hybridization temperature of 55c . we employed a dna volume of 25 l according to pcr criteria , as described below . the amplified fragments were visualized by using the gelred nucleic acid gel stain , 10,000 x ( biotium , hayward , ca , usa ) , and 2.5% agarose gel . information about personal data , sociodemographic characteristics , educational level , blood type , rhesus factor , eating habits , smoking , and alcohol consumption were evaluated using a predetermined questionnaire . furthermore , all participants gave their consent after the study protocol had been explained to them . 387 ( article 25 ) dated 31 july 2006 about ethical trials in algeria , we obtained the required access authorizations to the concerned health facilities in order to accomplish our study protocol . furthermore , we obtained informed written consent from all participants and their treating physicians after the study protocol had been explained to them . il-1-31 and il-1-511 polymorphisms are single nucleotide changes in the promoter region , while the il-1rn polymorphism is a repetition of 86 bp in the second intron . the dna was extracted from 200 l whole blood samples , 20 mg of fresh gastric biopsy , or buccal swab in h. pylori transport medium using an extraction kit ( magazorbe genomic dna , promega , fitchburg , wisconsin , usa ) stored at 20c . genotyping of the two polymorphisms ( il-1-31 and il-1-511 ) was performed using the restriction fragment length polymorphism method ( pcr - rflp ) ( table 1 ) ( 6 , 10 ) . briefly , 2550 ng of dna was used in a volume of 25 l with 150 mm dntp , 6.25 pmol of each primer , 1 u of dna polymerase gotaq g2 hot start polymerase ( promega , fitchburg , wisconsin , usa ) , 5% dmso , 4 mm mgcl2 , and 5 l of 5x pcr buffer gotaq . the amplified / digested fragments were visualized with the gelred nucleic acid gel stain , 10,000 x ( biotium , hayward , ca , usa ) in 2.5% agarose gel . primers and conditions for analysis of the il-1 and il-1rn polymorphisms tm : melting temperature ; il-1-31 : cluster of gene encoding interleukin-1 in the promoter region of tata box at the 31 position ; il-1-511 : cluster of gene encoding interleukin-1 in the promoter region of tata box at the 511 position ; il-1rn : gene encoding the anti - inflammatory antagonist ( interleukin-1ra ) . variable numbers of tandem repeats ( vntr ) analysis in the second intron of the il-1rn gene was carried out by pcr . the different alleles were identified by the size of the pcr fragments and encoded in a conventional manner ( 6 , 13 ) as follows : allele 1 ( four repetitions ) , allele 2 ( two repetitions ) , allele 3 ( five repetitions ) , allele 4 ( three repetitions ) , and allele 5 ( six repetitions ) . according to previous studies ( 6 , 13 ) , as described in table 1 , the il-1rn alleles were dichotomized into two categories : long genotype ( l:>three repetitions ; alleles 1 , 3 , 4 , 5 ) and short genotype ( 2 : two repetitions ; allele 2 ) . data were processed and analyzed using spss 22.0 ( statistical package for the social sciences , ibm corporation ; chicago , il , august 2013 ) . chi - square test was used to evaluate differences in the distribution of polymorphisms between different groups . all allelic distributions were examined for the corresponding differences of their hardy - weinberg equilibrium . the relative risk was evaluated by multivariate logistic regression based on categorical reference predictor models , adjusting for sex and age with a confidence interval ( ci ) of 95% and statistical significance set at p<0.05 . allelic combinations of models of the three variants closely related polymorphisms of il-1 and il-1rn were analyzed . the study of the haplotypes and linkage disequilibrium between loci ( estimated by r 
  and d ) was carried out via the web interface in the linkdos ( www.genepop.curtin.edu.au/linkc.html ) . the mean age of all participants was 45.017.67 years , and ranged from 16 to 86 years . in healthy individuals , the mean age was 35.812.72 years with a male - to - female ratio of 1:1 ( table 2 ) . however , in patients with ag and/or gc , mean ages were 49.319.35 ( male - to - female ratio of 0.56:1 ) and 59.314.00 years ( male - to - female ratio of 2.27:1 ) , respectively . comparison between groups according to gender ag : atrophic gastritis ; gc : gastric carcinoma ; hc : healthy controls comparison between the three groups using chi - square test . the frequencies of the tested genotypes were in hardy - weinberg disequilibrium according to the following results . linkage disequilibrium analysis between il-1-31 and il-1-511 for ag patients gave the following results : r=0.6804 , d=0.46294 ; moreover , analysis of linkage disequilibrium between il-1-31 and il-1-511 in gc patients : r=0.69357 , d=0.48 . considering the whole studied population , il-1rn was positively correlated ( r=0.424 , r=0.180 ) with il-1-31 ( p=0.023 ) and with il-1-511 ( p=0.006 ) . in patients with gc , we noticed weak positive correlations ( r=0.377 , r=0.142 ) of il-1rn with il-1-31 ( p=0.550 ) and il-1-511 ( p=0.056 ) , respectively . non - significant correlations ( r=0.454 , r=0.206 ) between il-1rn , on the one hand , and il-1-31 ( p=0.703 ) and il-1 -511 ( p=0.072 ) , on the other hand , were observed in patients with ag . nevertheless , the correlations were non - significant in healthy subjects ( p=0.134 for il-1-31 and p=0.058 for il-1-511 ) . as depicted in table 3 , the frequency of l / l wild - type pattern of il-1rn was 87.5% in controls compared to 62.5% in gc and 82.1% in ag patients . the il-1rn2 allele rates , for either heterozygous or homozygous , were 37.5% in gc , 17.9% in ag , and 12.5% in controls . distribution of the genotypes in the study population ag : atrophic gastritis ; gc : gastric carcinoma ; all : atrophic gastritis and gastric carcinoma ; hc : healthy controls ; il-1-31 : cluster in gene encoding interleukin-1 in the promoter region of tata box at the -31 position ; il-1-511 : cluster in gene encoding interleukin-1 in the promoter region of tata box at the 511 position ; il-1rn : gene encoding for the anti - inflammatory antagonist ( interleukin-1ra ) ; l : long genotype ( more than three repetitions ; alleles 1 , 3 , 4 , 5 ) ; 2 : short genotype ( two repetitions ; allele 2 ) ; c or t : single nucleotide polymorphisms . regarding the il-1-511 , the proportions of c / c wild - type pattern were 56.3% in healthy subjects , 47.5% in gc , and 23.1% in ag patients . individuals carrying the allele il-1-511 t are represented by 76.9% of ag , 52.5% of gc , and 43.8% of healthy controls . our results show that 53.1% of healthy subjects , 35.9% of patients with ag , and 25.0% of patients with gc have the t / t wild - type pattern of il-1-31 . as illustrated in table 4 , we investigated major genotypes implicated as risk factors for having gc and ag compared to controls . when multivariate logistic regression analysis was performed , our results showed that the c / c homozygous 4.614 ( 95% ci , 1.43714.817 ) and the c / t heterozygous 1.974 ( 95% ci , 0.5626.939 ) genotypes of the il-1-31 each indicated a strong contribution to gc . likewise , the same genotypes have non - significant risk of having ag ( c / c : 2.429 [ 95% ci , 0.7697.673 ] and c / t : 1.455 [ 95% ci , 0.4025.260 ] ) . however , the association between the two homozygous and heterozygous genotypes c / t and t / t of il-1 -511 was 4.286 ( 95% ci , 1.54411.898 ) times more at risk of having ag compared to controls . regression analysis of the distribution of the genotypes in the study ag : atrophic gastritis ; gc : gastric carcinoma ; hc : healthy controls ; or : odds ratio . gc * hc : regression analysis of combined gastric carcinoma and healthy controls , ag * hc : regression analysis of combined atrophic gastritis and healthy controls , ag * gc : regression analysis of combined atrophic gastritis and gastric carcinoma . il-1-31 : cluster in gene encoding interleukin-1 in the promoter region of tata box at the 31 position ; il-1-511 : cluster in gene encoding interleukin-1 in the promoter region of tata box at the 511 position ; il-1rn : gene encoding the anti - inflammatory antagonist ( interleukin-1ra ) ; l : long genotype ( more than three repetitions ; alleles 1 , 3 , 4 , 5 ) ; 2 : short genotype ( two repetitions ; allele 2 ) ; c or t : single nucleotide polymorphisms . concerning the heterozygous genotype l/2 of il-1rn , our findings show that the odds ratio of having gc was 4.200 ( 95% ci , 1.23014.337 ) . further analysis of combined genotype between il-1rn and il-1-31 ( table 5 ) and il-1rn and il-1-511 ( table 6 ) was performed using  test . the association between il-1-31 and il-1rn was significant in ag patients ( p=0.028 ) and in controls ( p=0.021 ) . furthermore , the relationship between il-1rn and il-1-511 was significant for the same groups ( ag : p=0.014 , and hc : p=0.015 ) . distribution of genotypes among patient groups regression analysis of combined ( il-1rn vs. il-1-31 ) chi - square test . ag : atrophic gastritis ; gc : gastric carcinoma ; hc : healthy controls ; il-1-31 : cluster in gene encoding interleukin-1 in the promoter region of tata box at the 31 position ; il-1-511 : cluster in gene encoding interleukin-1 in the promoter region of tata box at the 511 position ; il-1rn : gene encoding for the anti - inflammatory antagonist ( interleukin-1ra ) ; l : long genotype ( more than three repetitions ; alleles 1 , 3 , 4 , 5 ) ; 2 : short genotype ( two repetitions ; allele 2 ) ; c or t : single nucleotide polymorphisms . distribution of genotype among patient groups regression analysis of combined ( il-1rn and il-1-511 ) chi - square test . ag : atrophic gastritis ; gc : gastric carcinoma ; hc : healthy controls ; il-1-31 : cluster in gene encoding interleukin-1 in the promoter region of tata box at the 31 position ; il-1-511 : cluster in gene encoding interleukin-1 in the promoter region of tata box at the 511 position ; il-1rn : gene encoding for the anti - inflammatory antagonist ( interleukin-1ra ) ; l : long genotype ( more than three repetitions ; alleles 1 , 3 , 4 , 5 ) ; 2 : short genotype ( two repetitions ; allele 2 ) ; c or t : single nucleotide polymorphisms . the paradigm of previous studies on gc with regard to different haplotypes of il-1rn and il-1 has been investigated since 2000 on scottish and polish populations ( 6 , 7 ) . the genotype carriers of homozygous il-1-31c and il-1rn2 have a high risk of hypochlorhydria as a result of h. pylori infection with evidence for genetic machado et al . ( 13 ) reported results on a portuguese population by studying the etiological role of il-1-511 t allele , il-1rn2 allele , and their association with an increased risk of developing intestinal gc . until now , polymorphisms in genes of the pro - inflammatory cytokines il-1 and tnf- constitute an increased risk of developing gc in different gastric anatomical sites when the patients ethnicity is not considered ( 1719 ) . several studies on the association between il-1 and the il-1rn genotype in asian and caucasian populations show that il-1-511 t is significantly associated with the risk of gc ( 20 ) . other studies showed that il-1-511 t and il-1rn2 were associated with an increased risk of developing gc in caucasians . similarly , a significantly increased risk was noticed when analyses showed positive associated with h. pylori infection with a moderate increase among hispanics , but not among asians ( 15 , 2123 ) . to the best of our knowledge , only one study on the il-1 and il-1rn polymorphisms and their association with gastric cancer was performed in an arab population , namely in oman . the authors found that the il-1rn2 polymorphism increases the risk of gc , but the il-1-31c allele was not associated with the risk of developing gc ( 24 ) . in africa , kimang'a studied the association of these polymorphisms with h. pylori infection with different pathologies of the gastric mucosa without considering gc . he reported a significant effect of the il-1-511 t allele on gastritis , gastrointestinal reflux and gastric ulcers ( 25 ) . in this study , we evaluated the association between il-1 and il-1rn vntr polymorphisms and the risk of ag and cg in northwestern algeria . according to globocan 2012 , gc is the fourth most common cancer ( both genders ) in algeria , with about 686 cases per year ( 26 ) . our results show that the il-1-31c allele is associated with an increased risk of developing gc ( or=4.614 ; p=0.01 ) . the il-1rn2 heterozygous allele type is significantly associated with ag ( or=4.2 ; p=0.022 ) . these findings are in concordance with results on caucasians but different from those of asian and arab populations in oman ( 24 , 27 ) . considering the il-1-511 t allele , no significant effect on gc was noticed in the studied patients . this result is in agreement with studies on japanese and korean populations ( 27 , 28 ) , but different from results from caucasian populations ( 7 , 13 ) . individuals carrying the il-1-511 t allele have more risk of developing ag ( or=4.286 ; p=0.005 ) than gc . contrariwise , in a recent study from mexico , individuals carrying il-1-511c and il-1-31 t alleles separately are more likely to develop ag and gastric ulcers ( 30 ) . moreover , this work investigated the association between h. pylori infection and polymorphisms in only two genes , il-1 and il-1rn , without invoking other carcinogenic factors ; this could be considered as another limitation . in conclusion , the presence of il-1 and il-1rn polymorphisms with h. pylori infection of the gastric mucosa contributes to the development of chronic ag and gcs in an algerian population . individuals carrying the il-1-31c and il-1rn2 alleles are more likely to have an increased risk of developing gc . on the other hand these results highlight the importance of ethnicity studies about the effect of il-1 and il-1rn polymorphisms associated with h. pylori infection on gastric carcinogenesis . thus , large investigations needed to gain a proper understanding of gastric mucosa carcinogenesis in our region . the authors have not received any funding or benefits from industry or elsewhere to conduct this study .