Combined detection of serum Dickkopf‐1 and its autoantibodies to diagnose esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) can be treated effectively if diagnosed at an early stage. We evaluated whether measurement of Dickkopf‐1 (DKK‐1) in combination of DKK‐1 autoantibodies in serum may benefit early diagnosis of ESCC. Serum DKK‐1 and DKK‐1 autoantibodies were measured by enzyme‐linked immunosorbent assay in a training cohort (185 ESCC samples vs. 97 normal controls) and validated in a validation cohort (104 ESCC samples vs. 53 normal controls). Receiver operating characteristic (ROC) was applied to calculate diagnostic accuracy. Testing of DKK‐1 and DKK‐1 autoantibodies together could differentiate ESCC from normal controls (area under the ROC curve [AUC] 0.769, 95% confidence interval (CI), 0.715–0.823, 50.3% sensitivity, and 90.7% specificity in the training cohort; AUC 0.752, 95% CI, 0.675–0.829, 50.0% sensitivity, and 84.9% specificity in the validation cohort). Importantly, the diagnostic performance of the combination of DKK‐1 and DKK‐1 autoantibodies persisted in early ESCC patients (AUC 0.780, 95% CI, 0.699–0.862, 50.0% sensitivity, and 90.7% specificity in the training cohort; AUC 0.745, 95% CI, 0.626–0.865, 53.8% sensitivity, and 84.9% specificity in the validation cohort). Furthermore, the levels of serum DKK‐1 or DKK‐1 autoantibody after surgical resection were lower, respectively, compared with the corresponding preoperative samples (P < 0.05). Our results suggest that measurement of DKK‐1 combined with DKK‐1 autoantibodies is a potentially valuable tool for the early detection of ESCC.