In addition, by binary logistic regression, we observed that a high nuclear expression of Id-1 in primary ESCC tumours significantly predicted the development of distant metastasis of the corresponding patients within 1 year of oesophagectomy (odds ratio: 4.615, 95% CI: 1.596–13.348, P=0.005). Here, ID1 is linked to esophageal squamous cell carcinoma.