Interestingly, when we tried to find the origin of the heterogeneity in CSC markers and ESCC, we found that, as same as the result of the association of Bmi-1 and OS, the heterogeneity was lower and the result was significantly changed (HR = 2.03, 95%CI: 1.47–2.82, P < 0.001, I2 = 10, Ph = 0.34) if we discarded the study of Chen 201315. Here, BMI1 is linked to esophageal squamous cell carcinoma.