title: Ethnic difference in serology of Helicobacter pylori CagA between Japanese and non-Japanese Brazilians for non-cardia gastric cancer.
abstract: The usefulness of serology against CagA of Helicobacter pylori as a biomarker to identify high-risk individuals for non-cardia gastric cancer (ncGC) remains unclear among several ethnic populations with a high prevalence of cagA-positive strains. We investigated ethnic differences of CagA serology in two sets of case-control subjects, Japanese-Brazilians (JB) and non-Japanese Brazilians (NJB). We performed a cross-sectional comparison of IgG antibody titers to CagA (CagA-Ab) and the combination of CagA-Ab with conventional surface antigen (Hp-Ab) in 80 JB and 178 NJB ncGC patients and their controls (160 JB and 178 NJB). The level of CagA-Ab titer in cancer cases was significantly higher in NJB than in JB. The strength of the association between CagA-Ab seropositivity (+) (> or = 10 U/ml) and ncGC was almost 2-fold higher in NJB than in JB [odds ratio (OR) (95% confidence interval), 4.5 (2.6-7.8) and 2.1 (1.2-3.6), respectively]. However, in both JB and NJB, the OR was highest in CagA-Ab(+) subjects with low titer (10-29 U/ml), and decreased inversely with elevating CagA-Ab titer. In addition, the serological status of CagA-Ab(+) and Hp-Ab(-) showed a similar close association with ncGC between JB and NJB [5.4 (1.9-15.3) and 5.4 (2.0-15.0), respectively]. These results suggest that although the roles of CagA in the carcinogenic process of ncGC might be different between JB and NJB, the CagA-Ab could be a useful marker for ncGC, independently of ethnicity, particularly in high-risk individuals with the serological status of CagA-Ab(+) with low IgG titer or combined with Hp-Ab(-).
authors.affiliation: Epidemiology and Biostatistics Division, National Cancer Center Research Institute East, 6-5-1 Kashiwanoha, Kashiwa, Chiba 277-8577.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Tatemichi
authors.forename: Gerson Shigeaki
authors.initials: GS
authors.lastname: Hamada
authors.forename: Inês Nobuko
authors.initials: IN
authors.lastname: Nishimoto
authors.forename: Luiz Paulo
authors.initials: LP
authors.lastname: Kowalski
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Iriya
authors.forename: Joaquim Josê Gama
authors.initials: JJ
authors.lastname: Rodrigues
authors.forename: Shoichiro
authors.initials: S
authors.lastname: Tsugane
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000907:Antibodies, Bacterial / Q000097:blood*; D000942:Antigens, Bacterial / Q000276:immunology*; D001284:Atrophy; D001426:Bacterial Proteins / Q000276:immunology*; D015415:Biomarkers; D001938:Brazil / Q000453:epidemiology; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D005260:Female; D005753:Gastric Mucosa / Q000382:microbiology / Q000473:pathology; D016481:Helicobacter Infections / Q000208:ethnology*; D016480:Helicobacter pylori / Q000145:classification* / Q000235:genetics / Q000276:immunology; D006801:Humans; D007564:Japan / Q000208:ethnology; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D012306:Risk; D016036:Seroepidemiologic Studies; D013274:Stomach Neoplasms / Q000453:epidemiology / Q000208:ethnology* / Q000382:microbiology
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D015415:Biomarkers; C080866:cagA protein, Helicobacter pylori