MKI67 and cancer: Additionally, some studies concluded that high-expression of Ki67 is associated with poorer prognostic indicators, including progression free survival (PFS), cancer specific survival (CSS), recurrence free survival (RFS), and overall survival (OS) in NMIBUC patients, which is particularly prominent in Europe and the United States; however, among Asian NMIBUC patients with recurrence and progression, the correlation between Ki67 expression and the above indicators is not obvious (12).