Low Prevalence of Helicobacter pylori-negative Gastric Cancer among Japanese

The true prevalence of Helicobacter pylori-negative gastric cancer (HpNGC) is unknown. We attempt to clarify the prevalence and clinicopathologic features of HpNGC in Japanese.Helicobacter pylori infection was detected by antibody titer and microscopic observation. In addition, we confirmed the lack of endoscopic atrophy and histologic gastritis. In these cases, we added urea breath test or rapid urease test to confirm the absence of H. pylori. The mucus phenotype of gastric cancer tissue was also evaluated by immunohistochemistry.We screened 3161 gastric cancer cases from 1996 to 2010, and 21 cases were regarded as H. pylori negative. Clinically, patients with HpNGC were younger than patients with H. pylori-positive gastric cancer (controls), and revealed a lack of male dominancy. Histologically, diffuse type was frequently found. All patients examined were pepsinogen negative. Among HpNGC cases with endoscopic resection, the depressed macroscopic appearance was dominant. The prevalence of HpNGC was calculated as 0.66% (95% confidence interval = 0.41-1.01). The mucus phenotype of HpNGC was similar to that of the controls.The prevalence of HpNGC is very low and its pathological characteristics are different from common gastric cancer.