Similarly, such significant relationships between mTOR/p-mTOR expression and unfavorable prognosis of ESCC were still statistically reliable within the pooled analyses of three studies for DFS outcomes (HR: 2.39; 95 % CI: 1.64–3.49; P < 0.001; I2 = 0.0 %, p = 0.970; Table 4 and Fig. 3) [44–46] and two studies for CSS outcomes (HR: 1.62; 95 % CI: 1.18–2.23; P = 0.003; I2 = 0.0 %, p = 0.853; Table 4 and Fig. 3) [41, 43]. This evidence concerns the gene MTOR and esophageal squamous cell carcinoma.