The incidence of gastric cancer varies markedly throughout the
world, and it occurs about twice as commonly in males than females
(3). The highest incidence rates are currently observed in
East Asia (about 60 cases per 100,000 males in Japan and Korea)
(3). In all parts of the world, H. pylori is the strongest known risk
factor for gastric cancer (3, 4). Regions of the world with a low
prevalence of H. pylori infection tend to have a relatively low incidence
of gastric cancer, but geographic variation in gastric cancer
rates cannot be explained entirely by variations in H. pylori
prevalence. For example, populations in many parts of Africa and
India have a high prevalence