Objective:To explore the effects and possible mechanism of epidermal growth factor on the cyclooxygenase-2 expression in PC-3 cells. Methods:COX-2 expression in the PC-3 cells was detected by RT-PCR and Western Blot assay after stimulated with recombinant human epidermal growth factor(EGF)(1 μg/L,10 μg/L,100 μg/L) for 24 h;then LY294002(20 μmol/L),SC203580(20 μmol/L) and ZD1839(2 μmol/L) was used to treat PC-3 cell in combination with EGF(10 μg/L). The cyclooxygenase-2 protein expression was determined by Western blot assay. Results:The COX-2 expression in PC-3 cell was significantly increased after exposured to EGF(1~100 μg/L) for 24 h. LY294002,SC203580 and ZD1839 could prevent the expression of COX-2(P < 0.05).Couclusion:EGF could induce the upregulation of COX-2 in PC-3. LY294002 and SC203580 might be involved during the course.