We used a random-effects model in sensitivity analysis (as shown in Figure 4) (a: gender; b: high, middle and low differentiation; c: tumor stage; d: vascular invasion; e: nerve invasion; f: lymph node metastasis; g: T stage; h: pathological type of patients with biliary tract carcinoma), deleting each study in each round, to further determine the validity of HER2’s prognostic effects. This evidence concerns the gene ERBB2 and neoplasm.