Cytokine expression associated with Helicobacter pylori and Epstein‐Barr virus infection in gastric carcinogenesis

Helicobacter pylori and Epstein‐Barr virus (EBV) infection, and associated cytokines are involved in gastric carcinogenesis. We investigated the expression of these cytokines and their relationship with clinicopathological characteristics. The study included specimens from 207 patients with gastric adenocarcinoma, 56 with chronic gastritis, 32 with metaplasia, and 30 with low‐grade epithelial dysplasia. Tissue microarrays were constructed and immunohistochemical staining for IL‐1β, IL‐6, IL‐10, IL‐17, p16, p21, TNF‐α, and TNFR1 was performed. EBV and H. pylori infection status was determined. IL‐1β, IL‐6, IL‐17, p16, and p21 protein expression was significantly higher in adenocarcinoma cases than in the other cases (p < 0.05). EBV was only noted in adenocarcinoma (13 cases, 6.3%). The H. pylori infection rate in adenocarcinoma was significantly higher than that in the other cases (p < 0.005). IL‐6 expression was associated with improved survival (p < 0.05), whereas IL‐17 expression was associated with decreased survival (p < 0.05). IL‐6 expression was inversely associated with angioinvasion, and disease stage (p < 0.05), whereas IL‐17 expression was associated with disease stage (p < 0.05). IL‐10 expression was correlated with IL‐1β and TNF‐α expression, and p16 expression was correlated with IL‐17 and EBV status. Our results indicate that IL‐6 and IL‐17 are associated with gastric carcinogenesis and may be considered prognostic factors.