Serum CD26 levels in patients with gastric cancer: a novel potential diagnostic marker

Background: CD26 is an ectoenzyme with dipeptidyl peptidase 4 (DPP4) activity expressed on a variety of cell types. Considering that serum CD26 levels have been previously associated with different cancers, we examined the potential diagnostic value of serum CD26 levels in gastric cancer.Methods: Soluble serum CD26 levels were measured in pre and postoperative serum samples of 30 patients with gastric cancer and in 24 healthy donors by a specific ELISA kit.Results: We found significantly lower serum CD26 levels in patients with gastric cancer (557.7 +/- 118.3 pg/mL) compared with healthy donors (703.4 +/- 170.3 pg/mL). Moreover patients with HER2 positive tumors had significantly lower CD26 serum levels (511.8 +/- 84.8 pg/mL) compared with HER2 negative tumors (619.1 +/- 109.9 pg/mL, p = 0.006). A binary logistic model having gastric cancer as the dependent variable while age, gender, CEA, CA19.9 and CD26 levels as covariates, showed that CD26 serum levels were independently associated with gastric cancer presence. Indeed after 3 months from surgery serum CD26 levels significantly increased (700.1 +/- 119.9 pg/mL vs 557.7 +/- 118.3 pg/ml) in all patients (t = -4.454, p < 0.0001).Conclusions: This is a preliminary study showing that the measurement of serum CD26 levels could represent an early detection marker for gastric cancer.