Abstract: Objective To study the difference of S-TK1 level among patients with breast cancer,patients with benign breast tumor and healthy volunteers,to investigate the correlation between S-TK1 level and staging,the size of tumor,grade,ER,PR or HER-2 in patients with breast cancer and analyze the mechanism that S-TK1 involved into the recurrence and metastasis of breast cancer patients. Methods The S-TK1 levels of breast cancer,breast benign tumor and healthy volunteers were detected by enhanced chemiluminescence(ECL) dot blot assay. Results (1)The concentrations of S-TK1 in patients with breast cancer before treatment(group A)，benign breast tumor(group B)（17.98±10.20）pmol/L, and healthy volunteers(group C)（1.50±1.02）pmol/L and （0.88±0.45）pmol/L,respectively.There was significant difference between group A and group B or group C(P<0.001,P<0.001)，and between group B and group C(P=0.017).Also in group A the concentration of S-TK1 of staging Ⅲ was significantly higher than that of staging Ⅱ,（21.54±11.85）pmol/L vs.=(14.05±6.19)pmol/L(P=0.018).(2)There was a positive correlation between the concentration of S-TK1 with grade,HER-2 and the size of tumor (r=0.596,0.324,0.397,P<0.001,P=0.042,P=0.011,respectively) and a negative correlation between ER and the concentration of S-TK1(r=-0.391,P=0.013).But the concentration of S-TK1 had correlation with PR(P＝0.395，r=-0.138);(3)The S-TK1 level in patients with recurrence and metastasis before therapy was higher than that in disease-free patients,(23.17±13.15)pmol/L vs.(14.31±5.50)pmol/L(P=0.011).The DFS in low and middle S-TK1 level was longer than that in high S-TK1 level,but there was not significant diference(P=0.138). Conclusion S-TK1 perhaps could be one of markers for early breast cancer diagnosis.The level of S-TK1 has relation with the progress of breast cancer,and results into recurrence and metastasis.