ASSOCIATION OF HELICOBACTER-PYLORI AND DIFFUSE-TYPE GASTRIC-CANCER

The major purpose of this study was to evaluate the association of Hel icobacter pylori and diffuse type gastric cancer (DGC) clinicopatholog ically (study 1). The second aim was to investigate genetic difference s of H. pylori in patients with DGC and intestinal type cancer (IGC) ( study 2). The prevalence of H. pylori and the types of histopathologic al changes were evaluated in resected early gastric cancer (DGC; 25 pa tients, IGC; 25 patients). Genetic differences of H. pylori in DGC pat ients (n = 19) and IGC patients (n = 22) were analyzed by polymerase c hain reaction (PCR) methods in terms of restriction fragment length po lymorphism patterns of the ureB gene and cagA gene positive rates. All patients had evidence of H. pylori infection in the resected stomach, but the positive rate for H. pylori in the area surrounding cancer wa s 52% (in DGC; 56%, IGC; 48%). But in 40.0% of DGC cases (10/25), muco sal atrophy and intestinal metaplasia were rarely seen in the area sur rounding cancer and the positive rate of H. pylori was 80.0% (8/10), i n contrast, in 60.0% of IGC cases (15/25), atrophy and metaplasia were progressed and positive rate of H. pylori was 26.7% (4/15) in the are a. UreB gene products from 89.5% of DGC cases (17/19) were unable to b e digested by Spe I. 31.8% of products from IGC cases (7/22) were also unable to be digested by Spe I? but the positive rate of cagA gene in this group was higher than other groups. The high prevalence of H. py lori infection in DGC patients suggests that H. pylori plays a role in the pathogenesis of DGC, but in the stomach with DGC, it is considere d atrophy and intestinal metaplasia are not so implicated in H. pylori , compared with IGC. A genetic specificity of H. pylori in DGC and IGC was indicated by the results, suggesting that H. pylori may play diff erent roles in the pathogenesis of DGC and IGC.