Ki-67 expression in luminal type breast cancer and its association with the clinicopathology of the cancer.

The aim of the present study was to examine Ki-67 expression in tissue of luminal type breast cancer and to investigate the association between the Ki-67 expression level and clinicopathology of breast cancer. A total of 62 patients with breast cancer were included in the study group, whereas 30 patients undergoing a health check-up who were diagnosed with breast hyperplasia were included in the control group. Levels of Ki-67 expression in patients of the two groups were assessed using fluorescent quantitative polymerase chain reaction. The association between Ki-67 and the clinicopathology of the cancer was investigated by analyzing cancer cell proliferation and migration by reducing Ki-67 expression in the human MCF-7 cancer cell line. Compared with the controls, Ki-67 expression was significantly increased in the serum and cancer tissue of breast cancer patients (P<0.05). Ki-67 mRNA expression was significantly higher in cancer tissue than that in the corresponding paracancerous tissue of breast cancer (P<0.05). In addition, a high expression of Ki-67 was positively correlated with the clinical staging of tumor, tumor size and lymphatic metastasis of breast cancer, with statistical significance (P<0.05). In MCF-7 cells with a reduced Ki-67 expression, the proliferation activity and migration of breast cancer cells were significantly reduced (P<0.05). In conclusion, Ki-67 may be involved in promoting the genesis and development of breast cancer by affecting the proliferation and migration of cancer cells.