Clinical significance of serum and tissue Dickkopf-1 levels in patients with gastric cancer

Background: Dickkopf-1 (DKK1), a secreted protein known as a negative regulator of the Wnt signaling pathway, has been implicated in tumorigenesis. However, the clinical significance of DKK1 in gastric cancer has not been clarified. Methods: Serum concentrations of DKK1 in 153 patients with gastric cancer and 173 healthy controls were assessed. For tissue DKK1, immunohistochemistry was performed in 144 cancer specimens from 153 patients and in an additional 265 consecutive gastric cancer specimens. Results: The serum DKK1 concentrations were significantly higher in the gastric cancer patients than in the healthy controls (p<0.001). At a cutoff concentration of 31.9150 pg/ml, the sensitivity and the specificity for gastric cancer diagnosis were 87.6% and 87.9%, respectively. The gastric cancer patients with a serum DKK1 level of >= 60.0 pg/ml had significantly diminished survival compared with the patients whose serum DKK1 levels were lower (p = 0.033). The DKK1 overexpression in the cancer specimens significantly correlated with the increased serum DKK1 concentrations. Conclusions: Serum DKK1 levels have the potential as a diagnostic marker at a low cutoff value and ass prognostic marker at a high cutoff value. Serum and tissue DKK1 levels may aid in diagnosing gastric cancer and predicting patient outcomes. (c) 2012 Elsevier B.V. All rights reserved.