Abstract: Objective:To investigate the role of Helicobacter pylori L-form (Hp-L) in the genesis and development of gastric carcinoma.Methods:The specimens of chronic atrophic gastritis (CAG),intestinal metaplasia (IM),gastric epithelial dysplasia (GED) and gastric carcinoma (GCa) were collected from each 40 cases,and 40 cases of chronic superficial gastritis (CSG) (mild) acted as control.Hp-L was examined in each group by Gram's staining and immunohistochemical stain (SP method);The expression of skp2 was detected by Immunohistochemistry (IHC) and ISH,and the expression of Ki-67 and p53 were also examined by IHC.Results:The positive rates of Hp-L in CAG,IM,GED and GCa were 22.5%,40.0%,65.0% and 55.0%,respectively,demonstrating an increasing trend except for GCa group.The positive rate of mRNA and protein of Skp2 in CAG,IM,GED and GCa in the positive Hp-L groups of GCa were higher than that in the negative groups.The difference had statistical significance (P<0.05-P<0.01).Conclusions:Hp-L may play an important role in the evolution course of CAG,IM,GED and GCa,and correlates to the development of gastric carcinoma.Its mechanism of promoting the occurrence and development of gastric carcinoma may up-regulate the expressions of skp2,Ki-67 and mutant p53.