Abstract: Objective To observe the effect of epidermal growth factor receptor (EGFR)sig-nal transduction inhibitor RG-14260 (RG)alone or combined with mTOR signal transduction inhibitor rapamycin (RA)on the proliferation and expression of decorin (DCN)in Ishikawa cells in vitro. Methods After treated with RG alone or combined with RA for 24 hours,immunohistochemical meth-od was used to detect the expression of proliferating cell nuclear antigens (PCNA).Reverse tran-scriptase-polymerase chain reaction (RT-PCR)and Western blot method were used to detect the ex-pression changes of DCN genes and proteins in cells respectively.Results RG alone or combined with RA were able to decrease the expression rate of positive PCNA cells in Ishikawa cells,promote the ex-pression of DCN genes and proteins,but the efficacy of combined application was more significant. Conclusion Single and combined applications of EGFR and mTOR signal transduction inhibitors can up-regulate the expression of DCN in Ishikawa cells at the levels of genes and proteins,and meanwhile the increased DCN can reinforce the inhibitory effect of signal transduction inhibitors on the cell prolif-eration.