Previously, Imsumran et al. have found that the expression level of IGF-I receptor (IGF-Ir) and IGF-II were related to the metastasis, invasion depth, and recurrence in patients with ESCC [60], indicating the potential values of using IGF members as the biomarkers for the prediction of recurrence and outcomes of ESCC patients. Here, IGF1 is linked to esophageal squamous cell carcinoma.