Abstract AIMS To determine the proliferation pattern of esophageal and gastric cardia epithelia, normal and with different severities of precancerous lesions, by measuring proliferating cell nuclear antigen (PCNA), Ki 67 and bromodeoxyuridine (BudR) incorporation. METHODS One hundred and seventy five esophageal biopsies and 45 gastric cardia biopsies were collected from symptom free subjects in Huixian. Of which, 24 esophageal biopsies were incubated with BudR. The avidin biotin peroxidase complex (ABC) method was used to detect PCNA, Ki 67 and BudR. Quantitative analysis of the immunostaining results was recorded as the number of positive cells per mm 2 of the biopsy epithelium.