MKI67 and esophageal squamous cell carcinoma: In the stepwise regression multivariable model, high Ki-67 expression was significantly associated with poor OS in patients with ESCA compared to that of the low expression (HR = 1.98, 95% CI [1.33–2.94], P < 0.001), suggesting that high Ki-67 expression is an independent prognostic factor in patients with ESCC.