Overexpression of DEK is an indicator of poor prognosis in patients with gastric adenocarcinoma.

Increased expression of the human DEK proto-oncogene (DEK) gene has been associated with numerous human malignancies. The DEK protein is associated with chromatin reconstruction and gene transcription, and is important in cell apoptosis. The present study aimed to elucidate the role of DEK with regard to gastric adenocarcinoma tumor progression and patient prognosis. DEK protein expression was analyzed using immunohistochemistry in 192 tumors paired with adjacent non-cancerous gastric mucosa that had been surgically resected from patients with primary gastric adenocarcinoma. The association between DEK expression and the clinicopathological characteristics of the patients was evaluated using the χ2 test and Fisher's exact test. The survival rates of the patients were calculated using the Kaplan-Meier method. Cox analysis evaluated the association between the expression of DEK and the survival rate of the patients. The DEK protein was expressed in 84 patients with gastric adenocarcinoma (43.8%) and in 20 of the paired normal gastric mucosa tissues (11.5%). The DEK expression rate was found to be associated with tumor size (P=0.006), tumor grade (P=0.023), lymph node metastasis (P=0.018), serous invasion (P=0.026), tumor stage (P=0.001) and Ki-67 expression (P=0.003). Furthermore, patients with gastric adenocarcinoma that expressed DEK had decreased disease-free (log-rank, 16.785; P<0.0001) and overall (log-rank, 15.759; P<0.0001) survival rates compared with patients without DEK expression. Patients with late-stage gastric adenocarcinoma that expressed DEK exhibited a lower overall survival rate compared with patients without DEK expression (P=0.002). Additional analysis revealed that DEK expression was an independent prognostic factor for the prognosis of gastric adenocarcinoma (hazard ratio, 0.556; 95% confidence interval, 0.337-0.918; P=0.022). From the results of the present study, it can be concluded that the detection of DEK protein expression in gastric adenocarcinoma tissues may be important for the diagnosis and prognosis of patients, and may be a targeted therapy for the treatment of gastric adenocarcinoma.