Microarray gene expression profiling of gastric epithelium tissue obtained from Helicobacter pylori infected patients. Gastric biopsy samples from H. pylori-positive patients (n=24) were compared with these of uninfected subjects (n=8). The patients clinical diagnoses included gastritis, peptic ulcer and gastric cancer. Patients who had received H. pylorieradication therapy or treatment with antibiotics within 4 weeks prior to the study were also excluded.