Background: Dendritic cells (DCs) are potent antigen-presenting cells that are central to the regulation, maturation, and maintenance of the cellular immune response against cancer. In contrast, CD4(+)CD25(+) regulatory T cells (Tregs) play a central role in self-tolerance and suppress antitumor immunity. In this study, we investigated the clinical significance of mature CD83(+) DCs and Foxp3(+) Tregs in the primary tumor and regional lymph nodes from the viewpoint of the two opposing players in the immune responses.

Methods: We investigated, immunohistochemically, the density of CD83(+) DCs and Foxp3(+) Tregs in primary lesions of gastric cancer (n = 123), as well as in regional lymph nodes with (n = 40) or without metastasis (n = 40).

Results: Decreased density of CD83(+) DCs and increased density of Foxp3(+) Tregs were observed in the primary tumor and metastatic lymph nodes. Density was significantly correlated with certain clinicopathological features. Poor prognosis was observed in patients with a low density of CD83(+) DCs and a high density of Foxp3(+) Tregs in primary lesions. For patients with metastatic lymph nodes, the density of CD83(+) DCs in negative lymph nodes was found to be an independent prognostic factor by multivariate analysis.

Conclusion: The density of CD83(+) DCs and Foxp3(+) Tregs was inversely correlated with tumor progression and reflected the prognosis of gastric cancer.