Objective To analyze the expressions of thymidine kinase 1 (TK1) and nuclear-associated antigen Ki-67 in triple negative breast cancer (TNBC) and their clinical significances.Methods One hundred and twenty tumor tissue sections of patients with breast cancer who were performed breast conservation treatment or modified mastectomy in the Second Affiliated Hospital of Qingdao University Medical College from June 2009 to December 2010 were collected,and there were 60 cases with TNBC and 60 cases with non-TNBC.The expressions of TK1 and Ki-67 in different breast tissues were detected by immunohistochemistry.The relationships between the expression status and clinicopathologic features were analyzed.Results The positive expression rates of TK1 in TNBC and non-TNBC were 83.33％ and 51.67％ respectively,with a significant difference (x2 =13.713,P =0.000).The positive expression rates of Ki-67 expression in TNBC and nonTNBC were 68.33％ and 31.67％ respectively,with a significant difference (x2=16.133,P =0.000).In TNBC,the expression of TK1 was related to histological staging (x2 =6.125,P =0.013),but it was not related to onset age (x2 =0.809,P =0.369),menopausal stutas (x2 =1.615,P =0.204),tumor size (x2 =0.054,P =0.816) and lymphatic metastasis (x2 =0.672,P =0.412).In TNBC,the expression of Ki-67 was related to histological staging (x2 =13.145,P =0.000) and lymphatic metastasis (x2 =6.182,P =0.013),but it was not related to menopausal stutas (x2 =1.018,P =0.313),onset age (x2 =2.377,P =0.123) and tumor size (x2 =2.401,P =0.121).The expression of TK1 was positively correlated with that of Ki-67 (r =0.369,P =0.023).The results of survival analysis showed that the disease-free survival rates of 5-year were 28.20％ and 66.70％ in the TK1 positive group and TK1 negative group,and the disease-free survival rates of 5-year were 24.30％ and 64.30％ in the Ki-67 positive group and Ki-67 negative group,with significant differences (x2 =4.194,P=0.041;x2 =4.540,P =0.033).Conclusion TK1 and Ki-67 are highly expressed in TNBC,and their expressions are correlated with histological staging and survival,which are expected to become prognostic indicators.