CEACAM5 and non-small cell lung carcinoma: ROC analysis showed that testing both DKK1 and CEA increased the detection accuracy for NSCLC bone metastases compared with CEA alone (AUC 0.797, 95% CI 0.746–0.848, sensitivity 82.9% and specificity 68.9%; DKK1 plus CEA vs. DKK1 alone P = 0.370; DKK1 plus CEA vs. CEA alone P = 0.0001).