The value of Ki-67 expression in the prognosis of triple negative breast cancer patients

Objective To investigate the value of Ki-67 expression in the prognosis of triple negative breast cancer (TNBC) patients. Methods The expression of Ki-67 in 100 cases of TNBC was detected by EnVision method. According to the median of Ki-67, the patients were divided into low expression group and high expression group. The value of Ki-67 expression in the prognosis of TNBC was analyzed. Results The median Ki-67 was 30%. There were 52 cases in the Ki-67 low expression (≤ 30%) group, and 48 cases in Ki-67 high expression (> 30%) group. The expression of Ki-67 was correlated with histological grade, tumor size and lymph node status (P < 0.01). Histological grade Ⅰ to Ⅱ and primary tumor T1 were independent influencing factors of high expression of Ki-67 (P < 0.01). Kaplan-Meier analysis showed that Ki-67 was statistically related to disease-free survival (DFS) and overall survival (OS) (P < 0.05). Univariate COX analysis showed that tumor size, lymph node status, Ki-67 were statistically correlated with DFS and OS (P < 0.05). Multivariate analysis showed that tumor size, lymph node status, and Ki-67 were independent prognostic factors of DFS and OS (P < 0.05 or < 0.01). Primary tumors with T1, non-metastatic lymph nodes, and higher expression of Ki-67 in TNBC patients had longer DFS and OS (P < 0.01 or < 0.05). Conclusions Low expression of Ki-67 (≤ 30%) is associated with poor disease stage and prognosis in TNBC. 30% may be the best cut-off value of Ki-67. Key words: Ki-67 antigen; Prognosis; Triple negative breast cancer; Clinical stage