Objective To study the expression of chemokine receptor 5 (CCR5) in breast cancer and metastatic axillary nodes and the frequency of polymorphism CCR5-△32,and its effect on breast cancer metastasis.Methods Specimens were collected from Aug.2008 to Jun.2009 in Department of Breast and Thyroid Surgery,Liaocheng People's Hospital.The relative expression quantity of CCR5 mRNA was detected by real-time fluorescence quantitative PCR (RT-PCR),and polymorphism CCR5-△32 was tested by DNA electrophoresis.The data was processed by SPSS software.Results 1.The relative expression quantity of CCR5 mRNA was significantly higher in breast cancer tissues than in paracarcinoma tissues(P ＜ 0.01)and breast fibroadenoma tissues (P ＜ 0.05).The difference of relative expression quantity of CCR5 mRNA had statistical significance between breast cancer tissues in stage Ⅱ and Ⅲ(P ＜ 0.05 ),but not between breast fibroadenoma tissues and paracarcinoma tissues(P ＞0.05).2.The relative expression quantity of CCR5 mRNA was significantly higher in metastatic axillary nodes than in nonmetastatic nodes (P ＜ 0.05 ).3.Polymorphism CCR5-△32 wasn't found in any specimen.4.The relative expression of CCR5 mRNA had connection with breast oncogene C-erbB-2 and whether there was axillary lymph node metastasis,but no connection with other immunological and biochemical indicators.Conclusions CCR5 mRNA is significantly higher expressed in breast cancer and metastatic axillary nodes.The interaction between CCR5 and its ligands promotes the progress of breast cancer and axillary lymph node metastasis.CCR5 can be taken as a molecular indicator to predict axillary lymph node metastasis in breast cancer and provides new targert for clinical therapy.