Multivariate Cox regression analysis confirmed that plasma WFDC2 concentration was an independent prognostic factor in gastric (HR = 1.04, 95% CI: 1.00–1.07, p = 0.019) and esophageal cancers (HR = 1.08, 95% CI: 1.02–1.13, p = 0.006). Here, WFDC2 is linked to esophageal cancer.