Objective    To identify the sialic acid binding adhesin (sabA) gene polymorphism of Helicobacter pylori stains from patients with gastric cancer or precancerous lesions.     Methods    The sabA gene CT repeats regulatory domain polymorphism of 42 pylori strains sampled from 24 patients with gastric cancer and 18 with precancerous lesions (intestinal metaplasia) were analyzed by PCR-SSP

sequencing and comparative genomes.     Results    Positive detection rate were 85%

and 83.3% for gastric cancer (20/24) and 88.9% for precancerous lesions (16/18). Among the positive stains

55% was identified with functional sabA in all sequenced strains. Sequencing on randomly picked 18 sabA regulatory domain positive strains indicated that gene polymorphism was observed in both base and amino acid levels. Clustering analysis demonstrated that these sequenced sabA regulatory domain

along with the internationally published 7 sequenced Helicobacter pylori

could be divided into two categories，a Chinese group and a Western group.     Conclusion    sabA gene CT repeats regulatory domain is generally presented in Chinese strains

with significant polymorphism at translational level. Clustering analysis indicates apparent geographical regional distribution of strains is seen for  functional sabA gene.