Expression of p53 in breast cancer and regulatory effects of 5-aza-2′-deoxycytidine on p53

Objective Tumor suppressor gene p53 can inhibit tumor cell growth,arrest cell cycle,and promote apoptosis.However,the effects of p53 on the pathogenesis of breast cancer have not been fully elucidated.The aim of this study was to explore the expression of p53 protein and the correlation with clinical pathologic features in breast cancer.Furthermore,the regulatory effects of 5-aza-2'-deoxycytidine on p53 in breast cancer cell line were also studied.Methods The expression of p53 protein in 80 cases of breast cancer and normal and adjacent tissue were determined by the immunohistochemical staining.The expressions of p53 mRNA and p53 protein in breast cancer cell line were determined by RT-PCR and Western blotting.Results The positive rate of p53 in breast cancer( 41.25%) was higher than that in the normal and adjacent tissue( 22.5%)( P 0.01).The expression of p53 was not significantly correlated with age,grade,stage and lymph node metastasis( P 0.05).The low expression of p53 both in mRNA and in protein levels were found in breast cancer cell line of MCF-7.The expression of p53 increased after 5-aza-2'-deoxycytidine administration.Conclusion p53 is highly expressed in breast cancer,which may play an important role in the development and progression of breast cancer.5-aza-2'-deoxycytidine,up-regulating the p53 expression in breast cancer cell line,which provides the evidents for the development of therapeutic drugs for the patients with low expression of p53 breast cancer.