['We investigated whether or not there are autoantibodies for DKK1 (Dickkopf-1) in patients with non-small cell lung cancer (NSCLC) and whether this autoantibody can be used for cancer detection.', 'The levels of DKK1 autoantibodies were determined in 93 NSCLC patients and 87 healthy controls.', 'We found that, in the sera, the presence of autoantibody against DKK1 was highly correlated with NSCLC. High anti-DKK1 autoantibody titres were found in the sera of NSCLC patients, whereas low or negative titres were found in the control group. The ROC curve results showed that autoantibody immunoassay exhibited 62% sensitivity and 84% specificity. The sensitivity for the detection of NSCLC in stage I also reach 64.3%. Furthermore, a combined ELISA assays for both DKK1 and autoantibody DKK1 increased sensitivity and classified 81.7% (76/93) of the NSCLC patients as positive, whereas only 13.8 % (12/87) of healthy volunteers were falsely diagnosed as positive.'] Is dickkopf-1 autoantibody a novel serological biomarker for non-small cell lung cancer?