Abstract: BACKGROUND AND AIM: To investigate the correlation between infection of helicobacter pylori L_form (Hp_L) and gastric carcinoma, and to investigate the effect of Hp_L on angiogenesis of gastric carcinoma. MATERIALS AND METHODS: Hp_L was examined in 130 patients with gastric carcinoma and 50 control group by Gram staining and immunohistochemical stain SP method. The latter method was also used to detect the CD34 expression to measure MVD,and their relationship with clinicopathologic factors were analyzed. RESULTS: The positive rates for Hp_L form in gastric carcinoma was 70.00％(91/130) by Gram staining, which was similar to the positive rate(73.85％) by immunohistoc_hemical stain (P>0.05). Hp_L infection rate in gastric carcinoma was much higher than in control group (67.69％ vs 24.00％,P<0.05). MVD in gastric carcinoma was significantly higher than control groups (P<0.05). The MVD in Hp_L positive gastric carcinoma correlated with vessel invasion, depth of invasion, metastasis to the paragastric and distant lymph nodes but not with tumor size (P<0.05). CONCLUSION: Hp_L infection correlated with occurrence of gastric carcinoma. Hp_L infection may be an important promoting factor in angiogenesis of gastric carcinoma and related to invasion and metastasis.

Key words: gastric carcinoma, helicobacter pylori L_form, microvessel density, CD34