By analyzing the effects of age, tumor size, lymph node status, ER, PR, HER2, KI-67, surgery and radiotherapy on the prognosis of breast cancer, we found that tumor size, positive lymph node status and KI-67 expression affected OS of BC patients in southern China, which showed significant statistical difference (P = 0.018, P = 0.000, P = 0.034 respectively) (Supplementary Fig. 1). The gene discussed is MKI67; the disease is breast cancer.