Abstract: BACKGROUND AND AIM: To investigate the correlation between infection of helicobacter pylori L-form (Hp-L) and invasion and metastasis of gastric carcinoma. MATERIALS AND METHODS: Infection of Hp-L was examined on 130 patients with gastric carcinoma and control group by Gram staining, immunohistochemical stain (SP method) and transmission electron microscopy. Immunohistochemical stain was used for measuring the protein expressions of VEGF and MMP-2 in 180 cases of gastric carcinoma and control group. RESULTS： The rate of Hp-L infection in gastric carcinoma was 67.69％(P<0.05).Compared with the control group, the positive rate of Hp-L form in gastric carcinoma group was notably high. The difference in the positive rates of VEGF and MMP-2 expressions between gastric carcinoma and control group was obvious (P<0.01).There was a definite correlation between infection of Hp-L and the expression of VEGF and MMP-2 (P<0.05). The positive rate of Hp-L in the gastric carcinoma group correlated with depth of invasion, metastasis to the paragastric and distant lymph nodes (P<0.01)but not tumor size. CONCLUSION： Hp-L infection correlated with the occurrence and progression of gastric carcinoma, and may be an important promoting factor in gastric carcinoma growth, invasion and metastasis.

Key words: gastric carcinoma, helicobacter pylori, L-form, invasion and metastasis, MMP-2