Immune cells in pancreatic cancer: Joining the dark side.

Pancreatic tumors are rich in immune cell infiltrates that include CD4+ T-cell subsets encompassing both regulatory T cells and TH17 cells. Rather than protecting the organism by exerting an anticancer effect, these T-cell subsets promote tumor formation. Thus, re-activation of antitumor immunity should be investigated for use in pancreatic cancer prevention and therapy.