Abstract: OBJECTIVE: To study the effect of retinoic acid on expression of nuclear matrix protein in human esophageal cancer cell EC9706， in order to further understanding of the relationship between esophageal carcinogenesis and nuclear matrix proteins. METHODS：Through cell culture and induction of differentiation treatment for 48 h， nuclear matrix protein selective extraction， two dimensional gel electrophoresis analysis to detect the expression of nuclear matrix protein in human esophageal carcinoma EC9706 before and after retinoic acid treatment. RESULTS：The expression of nuclear matrix protein showed great changes after treatment with retinoic acid in EC9706 cells. There were 18 marked changes during apoptosis induced by retinoic acid， with 11 up-regulated proteins，the 4 down-regulated proteins， and 3 new spots. CONCLUSION：This study suggested that the types and expression levels of nuclear matrix protein could change significantly after treatment by retinoic acid in human esophageal cancer EC9706 cells.

Key words: esophageal cancer, EC9706 cells, retinoic acid, nuclear matrix protein