Abstract: Objective:To examine the expression of glucocorticoid receptor in human colon cancinoma tis -sues and cell lines and to explore the survival of colon cancer cell lines treated with dexamethasone alone or in combination with 5-Fu and L-OHP in a way of dexamethasone pretreatment or co-administration in vitro. Methods:The expression of glucocorticoid receptor was detected in 61cases of colon cancer tissue samples and 4 types of colon cancer cell lines by immunohistochemistry. Apoptosis was detected by Hoechst33342 staining and flow cytometry. MTT assay was employed to detect the chemosensitivity of colon carcinoma cells to L-OHP and 5-Fu with dexamethasone pretreatment for 24hours or co-administration. Results: Positive GR expression was found in 57.3% colon cancer tissue samples and in Lovo and HCT- 116 cell lines, not in HT- 29 and SW- 480 . Apoptosis was detected in GR-expressed Lovo and HCT-116 cells at72hours after 1 × 10-4 mol/L Dex treatment, and the rates of apoptosis were higher than those in the control groups without Dex (P<0.01), GR-negative cells, HT-29 and SW-480 even treated with 1 × 10-4 mol/L Dex for72 hours. Pretreatment and co-administration for Lovo cells with1 × 10-4 mol/L Dex could decrease the IC50of L-OHP from 13.7 ± 1.3 μ g/mL to 5.9 ± 0.6 μ g/mL and 4.8 ± 0.7 μ g/mL, respectively. IC50of 5-Fu was decreased from 72.2 ± 8.1 μ g/mL to 21.1 ± 4.1 μ g/mL and 18.6 ± 4.0 μ g/mL, respectively. Conclusion:There is expression of glucocorticoid receptor in part of colon carcinoma tissue samples and cell lines. Apoptosis does occur in GR-expressed Lovo and HCT-116 cells induced by dexamethasone in vitro. Pretreatment for 24h and co-administration with Dex can increase the chemosensitivity of Lovo cells to L-OHP and 5-Fu.