Neural precursor cell-expressed, developmentally down regulated 9 (NEDD9), a member of Crk-associated substrate (CAS) family, is highly expressed in multiple cancer types and involved in cancer cell adhesion, migration and invasion. The prognostic value of NEDD9 has been evaluated before and its expression is a predictor of poor prognosis in cancer patients. The objective of this study was to determine the clinical significance of the serum levels of NEDD9 in gastric cancer (GC) patients.

A total of 68 patients with a pathologically confirmed diagnosis of GC were enrolled into this study. Serum NEDD9 concentrations were determined by the solid-phase sandwich (ELISA) method. Twenty-eight healthy age- and sex-matched controls were included into the analysis.

The median age at diagnosis was 60years, range 21 to 84years. Forty-nine (72%) patients were male and cardia was the most common tumor localization (n=37, 77%) in GC patients. The most frequent histologic subtype was adenocarcinoma (n=45, 66%). Liver was the most common metastatic site in 32 patients with metastasis (n=14, 44%). Sixty-one percent of 23 metastatic patients who received palliative chemotherapy (CTx) were CTx-responsive. The median follow-up time was 8months (range 1 to 23months). At the end of the observation period, 17 patients (25%) experienced disease progression and 28 of the remaining patients (41%) died. Median progression-free survival (PFS) and overall survival (OS) of the whole group were 4.0±0.7months [95% confidence interval (CI)=3–5months] and 14.6±1.2months (95% CI=12–17months), respectively. One-year and 2-year OS rates were 54.4% (95% CI=41.3–67.5) and 51.2% (95% CI=37.3–65.1), respectively. The median serum NEDD9 levels of GC patients were significantly higher than controls (1339.51 vs. 1187.91pg/mL, P=0.02). There was no significant difference according to known disease-related clinicopathological or laboratory parameters (P>0.05). Serum NEDD9 levels had a significant impact on PFS (P=0.04). On the other hand, serum NEDD9 levels showed no significantly adverse effect on OS (P=0.50).

Serum NEDD9 level may be a diagnostic marker for GC patients. Moreover, our study results showed that it was elevated in GC patients and had an unfavorable prognostic effect. However, it has no predictive role on CTx response.