Increased intratumoral interleukin 22 levels and frequencies of interleukin 22-producing CD4+ T cells correlate with pancreatic cancer progression.

Objective The objective of this study was to investigate the expression and clinical relevance of interleukin 22 (IL-22) and IL-22-producing CD4(+) T cells (IL-22(+)CD4(+) T cells) in pancreatic cancer (PC) tissues. Methods Interleukin 22 protein levels in PC tissues were measured by Western blot analysis and immunohistochemistry. The frequencies of IL-22(+)CD4(+) T cells in tumors and peripheral blood from PC patients and control subjects were analyzed by flow cytometry. The association between IL-22 and phosphorylation of STAT-3 was investigated in in vitro model. Results Interleukin 22 protein was more highly expressed in PC tissues than in peritumoral and normal pancreatic tissues. The frequencies of all IL-22(+)CD4(+) T cells and T helper 22 (T(H)22) cells (IL-22(+)IFN--IL-17(-)CD4(+)) were significantly higher in PC tissues than in the peripheral blood of PC patients and control subjects. It was observed that up-regulation pSTAT-3 and its downstream genes such as Bcl-2 and cyclin D1 in vitro. Finally, we found that increased intratumoral IL-22 expression and frequencies of T(H)22 and IL-22(+)CD4(+) T cells were positively correlated with PC tumor-node-metastasis staging. Conclusions Increased intratumoral IL-22 levels, IL-22(+)CD4(+) T cells, and T(H)22 cells are correlated with PC tumor-node-metastasis staging, suggesting that IL-22 and IL-22(+)CD4(+) T cells may be related to tumor progression and are potential therapeutic targets in patients with PC.