[Expression of Ki67 and clinicopathological features in breast cancer]

To analyze the relationship between the expression level of Ki67 and clinicopathological features in breast cancer.

Data of 918 female patients with invasive ductal breast carcinoma treated in the Cancer Hospital, Chinese Academy of Medical Sciences from Jan. to Dec. 2010 were analyzed retrospectively. The correlation of Ki67 expression and other clinicopathological features in the breast cancer was analyzed.

Among the 918 cases, the Ki67 index was 0.9% to 95% (mean value 27.8%). Taking the Ki67 index 14% as the boundary to divide the patients into two subgroups, 263 cases (28.6%) were ≤ 14%, and 655 cases (71.4%) were >14%. There were significant differences between the Ki67 expression and age, tumor size, axillary lymph nodes status, histological grade and the expressions of C-erbB-2, estrogen receptor (ER) and progesterone receptor (PR) (P < 0.05 for all). All the Ki67 indexes of Ki67 expression in luminal B (30.44%), HER-2 overexpression (36.77%) and triple negative (47.40%) subtypes were significantly higher than that in the luminal A subtype (21.36%)(P < 0.01). The expression level of Ki67 in triple-negative subtype (47.40%) was significantly higher than that in the non-triple-negative subtype (24.79%)(P < 0.001).

Ki67 index is significantly correlated with the age, tumor TNM stage, axillary lymph node status, histological grading, ER status, PR status and HER-2 status. A high expression level of Ki67 is a poor prognostic factor for breast cancer. The expression level of Ki67 should be detected routinely and it may become a useful prognostic marker in the treatment of breast cancer.