Copyright ©The Author(s) 2020.
World J Gastroenterol. Aug 28, 2020; 26(32): 4739-4752
Published online Aug 28, 2020. doi: 10.3748/wjg.v26.i32.4739
Table 1 Important finding on dupA of Helicobacter pylori in chronological order
YearObservation and conclusionSample locationSample sizeTechniques used in the studyProposed nameRef.
2005dupA was novel marker associated with increased risk for DU and reduced risk for gastric cancer in East Asia and South AmericaJapan, Korea, Colombia500PCR, southern blotdupALu et al[23]
2007Significant association of dupA gene with DUNorth India166PCR, Dot-blot hybridization, partial sequencingdupAArachchi et al[24]
2007Presence of dupA significantly associated with GC than DUBelgium, South Africa, china, North America258PCRdupAArgent et al[25]
2008dupA gene was not associated with any diseases outcomeIran157PCR, partial sequencingdupADouraghi et al[30]
2008dupA was not associated with H. pylori associated diseases in children and adultsBrazil482PCR, partial sequencingdupAGomes et al[26]
2008dupA was associated with peptic ulcer in Iraqi population but not with Iranian populationIraq and Iran108PCRdupAHussein et al[29]
2008There was no association between the occurrence of dupA and DUBrazil (Sao Paulo)79PCRdupAPacheco et al[27]
2008The prevalence of dupA was significantly higher in DU patients than in gastric cancerchina360PCRdupAZhang et al[38]
2009There was no consistent association between dupA and DU or GC developmentSweden, Australia, Malaysia (ethnic groups Indian, Malaya)243PCR, partial sequencingdupASchmidt et al[41]
2010dupA was not associated with gastroduodenal diseases or IL-8 productionJapan244PCR, partial sequencing RT-PCR, IL-8 assaydupANguyen et al[45]
2010dupA is not association with DU in patients from TurkeyTurkey91PCRdupATuncel et al[37]
2010Meta-analysis of case control studies confirmed the presence of dupA gene for DUAsian and western countries2466-dupAShiota et al[44]
2010Meta-analysis of previous report showed dupA gene promotes DU formation some population and GU and GC in othersAround the world2358dupAHussein et al[43]
2010In Taiwanese female population, MMP-3 promoter polymorphism is correlated with DU rather than dupA geneTaiwan female181PCRdupAYeh et al[40]
2010dupA and gastric cancer is negatively associated with GC in Japanese populationJapan136PCRdupAImagawa et al[46]
2010Proposed two alleles of dupA [dupA1 (intact), dupA2 (truncated)]. dupA1 (not dupA2) increased IL-12p40 and IL-12p70 production from CD14+ mononuclear cellUnited Kingdom, United States, Belgium, South Africa, China34PCR, full Sequencing, Cytokine ELISA, real tome PCR, flow cytometrydupA1Hussein et al[52]
2011Presence of mutation on dupA at 1311 and 1426 leads to stop codon called truncated dupABrazil252PCR, full sequencingdupAQueiroz et al[50]
2011Intact dupA (dupA1) without stop codon was associated with decreases rate of gastric carcinoma in Brazilian populationBrazil6Full sequencingdupA1Queiroz et al[57]
2012Found a positive association between presence of dupA and DU [OR 24.2; 95%CI: 10.6-54.8] and inverse association between presence of dupA and GU [OR 0.34; 95%CI: 0.16-0.68] and GC [OR 0.16; 95%CI: 0.05-0.47]Iran216PCRdupAAbadi et al[31]
2012Prevalence of dupA was higher in the eradication failure group than in the success group (36.3% vs 21.9%)Japan142PCR, Drug sensitivity testdupAShiota et al[60]
2012The logistic analysis report in Brazilian population showed the presence of intact dupA independently associated with duodenal ulcer (OR = 5.06; 95%CI: 1.22-20.96, P = 0.02)Brazil75SequencingIntact dupAMoura et al[51]
2012dupA gene was found to be significantly associated with DU than in NUD in south east Indian populationIndia140PCR, partial sequencing, real time PCR,dupAAlam et al[47]
2012Found a significant association between dupA1 and DU (P < 0.01) along with a significant higher level of gastric mucosa IL-8 in dupA1 than in dupA2 or dupA negative Iraqi strainIran68PCR, full sequencing, IL-8 ELISAdupA1Hussein et al[54]
2012classified dupA into two types (long types and short types) depend on the presence of 615 bp at the N-terminal of dupA. Found high prevalence of intact long type dupA (24.5%) than short type dupA (6.6%) and significantly associated with GU and GC than gastritis (P = 0.001 and P = 0.019) in Japanese populationJapan319PCR, full sequencingLong type and short typeTakahashi et al[53]
2012Complete dupA cluster (dupA with six virB homologues) was associated with DU rather than dupA gene only in United States populationUnited States245PCR and cytokine ELISAdupA clusterJung et al[75]
2013Prevalence of long type dupA (2499 bp) was significantly higher in GU, GC and DU (40.3%) than from gastritis (20.4%) (P = 0.02) in ChinaChina116PCR, Full sequencingdupA clusterWang et al[59]
2013PUD was significantly associated with cagA (P ≤ 0.017; OR 0.4; 95%CI: 0.18-0.85) rather than dupAIraq154PCRdupASalih et al[34]
2014dupA was found to play an important role in the development of DU, BGU and dysplasia in South Korean populationSouth Korea401PCRdupAKim et al[39]
2014dupA was associated with cagA and vacAs1m1 genotypesBrazil205PCRdupAPereira et al[28]
2014The prevalence of dupA and cagA were more in MTZ, CLR and AML resistance strain as compared to other virulence factor in PakistanPakistan46PCRdupARasheed et al[61]
2015cagA, complete dupA cluster and smoking were significantly associated with increased level of IL-8 production from gastric mucosa of Iraqi populationIraq81PCR, IL-8 ELISAdupAHussein et al[55]
2015Prevalence of dupA1 was significantly higher in DU than NUD (P = 0.02) in Indian strains and dupA1 positive strains were similar to East Asian strains and distinct from western strains.India170PCR, sequencing, IL-8 ELISAdupA1Alam et al[58]
2015Significant association of complete dupA cluster with IL-8 production (P < 0.01) in north East of ChinaChina262PCR, western blotting, IL-8 ELISAdupA clusterWang et al[76]
2015DupA protein have ATPase activity and play a role in apoptosis of gastric cancerous cells through mitochondrial pathway but neither adhere nor translocate to host cellChina1 (WH21)PCR, western blotting, ATPase, Adhesion, translocation and cytotoxic assayLong type dupAWang et al[79]
2015dupA1 have a significant association with A2147G clarithromycin resistance strain but not with Il-8 production from gastric mucosaIraq74PCR, IL-8 ELISA, antibiotic susceptibility teatdupA1Hussein et al[56]
2015Significant association between the presence of dupA and DU diseases (P = 0.03 OR 3.14, 95%CI: 1.47-7.8).Iran128PCRdupAHaddadi et al[35]
2015There was no significant relationship between dupA status and duodenal ulcer disease (P = 0.25) but, there was a converse relationship between dupA negative strains and gastric cancer disease (P = 0.02)Iran123PCRdupASouod et al[36]
2015There was no association of dupA gene with the ethnic group (Indian, Chinese, Malaya) of MalaysiaMalaysia105PCRdupAOsman et al[42]
2017Significant association of dupA gene with non-severe clinical outcome (P = 0.0032, OR 0.25, 95%CI: 0.09-0.65) and play a role in protecting against gastric cancer in ChileChile132PCRdupAParedes et al[48]
2017A complete tfs plasticity zone cluster including dupA is a virulence factor that may be important for the colonization of H. pylori and to the development of severe outcomes of the infection with cagA-positive strainsPortugal18PCR, whole genome sequencing, cytokine assaydupASilva et al[78]
2019dupA was significantly associated with decreased risk of duodenal ulcer (P = 0.024)Costa Rica151PCRdupAMolina Castro et al[49]
2019Significant relationship was observed between the occurrence of DU and the presence of the 112 bp segment (P = 0.002; OR 6.98; 95%CI: 1.94-25.00)Iran143PCRdupAFatahi et al[32]
2019The prevalence of dupA was 53.4% in South African population, but it was not associated with duodenal ulcerSouth Africa234PCRdupAIdowu et al[64]
2019The prevalence of dupA was higher (30.4%) in peptic ulcer (mild diseases) than gastric cancer (severe diseases) 18.2%Northern Spain102PCRdupAFernandez-Reyes et al[72]
2019dupA was present in 10/41 (24.4%) of population, and it was not associated with severe gastritisSwitzerland41Whole genome sequencedupAImkamp et al[63]
2019Significant association was found between metronidazole resistance and dupA genotypes (P = 0.0001)Iran68PCRdupAFarzi et al[33]