Torres J, Pérez-Pérez G I, Leal-Herrera Y, Muñoz O
Unidad de Investigación Médica en Enfermedades Infecciosas, Hospital de Pediatría, Instituto Mexicano del Seguro Social, Mexico City, DF.
Int J Cancer. 1998 Oct 29;78(3):298-300. doi: 10.1002/(SICI)1097-0215(19981029)78:3<298::AID-IJC6>3.0.CO;2-Q.
Helicobacter pylori strains possessing the Cag pathogenicity island have been associated with increased gastric inflammation and with duodenal ulcer. In contrast, studies on the association of cagA+ H. pylori infections and gastric cancer have shown conflicting results. The aim of our study was to determine whether H. pylori and CagA status are associated with gastric cancer in Mexico. We selected serum samples from 3 geographic areas with gastric cancer mortality rates per 100,000 inhabitants of 2.5 (low risk), 4.5 (medium risk) and 6.4 (high risk). H. pylori infection was determined by the detection of antibodies to H. pylori whole cell antigen by an enzyme-linked immunosorbent assay (ELISA). To study the prevalence of infection with cagA+ strains, serum IgG antibodies to CagA were determined by ELISA using a recombinant CagA antigen. Of the 2,775 individuals studied, 1,931 were H. pylori seropositive and 1,710 had antibodies against CagA. The risk for gastric cancer in the 3 populations studied increased proportionally as infection with cagA+ strains increased (p < 0.001 for trend). H. pylori infection also showed association with gastric cancer (p < 0.05). Individuals seropositive for CagA, but seronegative for H. pylori whole cell antigen, were more frequent in areas with higher gastric cancer rates (p < 0.01). These results support the possible role of CagA(+) status as predictor of risk for gastric adenocarcinoma in Mexico; this is in agreement with results in European and American populations, but contrary to studies in some Asian countries.
携带细胞毒素相关基因（Cag）致病岛的幽门螺杆菌菌株与胃炎症加剧及十二指肠溃疡有关。相比之下，关于cagA+幽门螺杆菌感染与胃癌关联的研究结果相互矛盾。我们研究的目的是确定在墨西哥幽门螺杆菌及CagA状态是否与胃癌有关。我们从3个地理区域选取了血清样本，这些区域每10万居民中胃癌死亡率分别为2.5（低风险）、4.5（中等风险）和6.4（高风险）。通过酶联免疫吸附测定（ELISA）检测幽门螺杆菌全细胞抗原抗体来确定幽门螺杆菌感染情况。为研究cagA+菌株的感染率，使用重组CagA抗原通过ELISA测定血清中抗CagA的IgG抗体。在2775名研究对象中，1931人幽门螺杆菌血清学检测呈阳性，1710人有抗CagA抗体。在所研究的3组人群中，随着cagA+菌株感染率上升，患胃癌的风险成比例增加（趋势p<0.001）。幽门螺杆菌感染也显示与胃癌有关（p<0.05）。在胃癌发病率较高的地区，CagA血清学检测呈阳性但幽门螺杆菌全细胞抗原血清学检测呈阴性的个体更为常见（p<0.01）。这些结果支持CagA(+)状态可能作为墨西哥胃腺癌风险预测指标的作用；这与欧美人群的结果一致，但与一些亚洲国家的研究结果相反。
