MKI67 and breast cancer: Ki-67 becomes the most reliable index in the detection of tumour cell proliferation activity due to its short half-life period [26], thus the expression of Ki-67 reflects the tumour proliferation rate and correlates with initiation, progression, metastasis and prognosis of a number of types of tumours; for example, correlation between Ki-67 expression and patients’ survival is proven in cervical, uterine and breast cancers, non-Hodgkin’s lymphoma and large bowel cancer [29].