Relationship between expression of Bcl-2 and p53 protein and CagA+ Helicobacter pylori in gastric cancer

Abstract

AIM:The relationship between cytotoxin-associated protein (CagA)+Helicobacter pylori (H.pylori) infection and gastric cancer in China was reported inconsistently. Using enzyme-linked immunosorbent assay (ELISA) to detect serum anti-CagA antibody and ABC immunohistochemical staining to detect the expression of Bcl-2 and p53 proteins, this study is to explore the relationship between CagA H.pylori infection and expressions of p53 and Bcl-2 proteins in gastric cancer and chronic gastric diseases. METHODS:Seventy-nine patients (50 with gastric cancer, 17 with chronic atrophic gastritis, 5 with gastric ulcer and 7 with chronic superficial gastritis) were diagnosed by endoscopy and biopsied under endoscopy for detection of H.pylori infection, and confirmed by pathological examination. Expression of Bcl-2 and p53 proteins was detected by immunohistochemistry. Rapid urease test and serum H.pylori antibodies with ELISA or Warthin-Starry silver stains were used for H.pylori diagnosis. H.pylori was defined as positive when 2 or 3 of these tests were positive. ELISA was used for the detection of serum anti-CagA antibody. RESULTS:Anti-CagA antibody was present in 43/50 (86 %) gastric cancer and in 13/29 (41 %) chronic gastric disease, CagA+ H.pylori rate in gastric cancer was higher than those in chronic gastric diseases (P 0.05). In CagA+ gastric cancer it was higher than that in CagAone (65 % vs 43 %, P >0.05), and in CagA+ chronic gastric diseases it was higher than that in CagAone (77 % vs 12 %, P <0.01). The positive rate of mutant p53 expression in gastric cancer was higher than that in chronic gastric diseases (54 % vs 28 %, P <0.05), in CagA+ gastric cancer it was significantly higher than that in CagAone (60 % vs 14 %, P <0.05), and in CagA+ chronic gastric diseases it was significantly higher than that in CagAones (46 % vs 12 %, P <0.05). CONCLUSION:Expression of anti-CagA antibody is present in a significantly higher percentage of gastric cancer subjects than that in chronic gastric diseases. It is suggested that CagA+ H.pylori infection may increase the risk of gastric cancer. The CagA factor may be involved in the development of gastric cancer through influencing the expression of Bcl-2 gene and mutant p53 gene. Du YJ, Zhao J, Zhao RB, Li BJ. Relationship between expression of Bcl-2 and p53 protein and CagA+ Helicobacter pylori in gastric cancer. Shijie Huaren Xiaohua Zazhi 2003;11(5):554-557 摘要 目的:CagA + H.pylori 感染与胃癌的相关性在我国报道不 一,且致癌机制不祥. 本研究应用 ELISA 法检测 H.pylori 相关胃癌和慢性胃病血清中抗CagA抗体和免疫组化方法 检测全部组织标本中 Bcl-2、p53 蛋白的表达,研究 H. pylori CagA 阳性株感染与胃癌、慢性胃病的相关性及与 胃黏膜组织中 Bcl-2、p53 蛋白表达的相互关系,探讨