Abstract: BACKGROUND AND AIM: To examine the expressions and their significance of oncogene protein MDM2, anti-oncogene protein P53 and cell cycle protein P27 in esophageal squamous cell carcinom and adjacent mucosa. MATERIALS AND METHODS: Immunohistochemistry was used to detect the expressions of MDM2, P53 and P27 proteins in eighty-five cases of esophageal squamous cell carcinoma and their corresponding adjacent mucosa. Flow cytometry(FCM) was applied to measure the quantities of these protein expressions in 48 fresh esophageal squamous cell cancers and adjacent tissue and 12 relatively normal mucosa at the edge of the excision. RESULTS: The changes of esophageal epithelia from simple hyperplasia to mild to moderate to severe dysplasia to carcinoma in situ and infiltrating carcinoma，revealed that the P53 protein was not expressed in normal mucosa but appeared in the early stages of esophagus carcinogenesis. The MDM2 and P27 proteins had different degrees of expression in normal esophageal mucosa,with MDM2 protein markedly increased in the advanced stages of esophageal cancer. CONCLUSION: P53 and P27 proteins appeared in the early stages of esophagus oncogenesis, however the changes of MDM2 expression occurred in the advanced stage of esophageal carcinogenesis. Flow cytometry quantitative and immunohistochemistry qualitative analyses of gene proteins, could explore the expressions of oncoproteins and their clinical significances.

Key words: esophageal squamous cell carcinoma, oncogene protein, immunohistochemistry, flow cytometry