Role of plasmacytoid dendritic cells in cancer

In the last decade, several studies have provided evidence that plasmacytoid dendritic cells (pDCs) actively participate in a wide spectrum of human diseases including infection, autoimmunity, and cancer. In particular, human neoplasms are populated by pDCs, whose presence is related to a poor prognosis. However, the role of tumor-associated pDCs (TApDCs) remains controversial. Various studies indicate that pDCs play an immunosuppressive role and facilitate tumor progression in both animal and human models. In contrast, others have found that the presence of activated pDCs results in tumor regression in mice. Given these findings, it is clear that pDC function plays a critical role in tumor biology. Understanding pDC biology in cancer represents an important necessity and will pave the road to novel therapeutic strategies to fight malignancies. In this chapter we will discuss novel findings about the therapeutic tools which are based on the pharmacological manipulation of tumor-associated pDCs.