Dendritic cells in the skin--potential use for melanoma treatment

Melanoma is an aggressive malignancy with poor prognosis. Eradication of tumor cells requires an effective interaction between melanoma cells and different players of the immune system. As the most potent professional antigen-presenting cells, dendritic cells (DCs) play a pivotal role in mounting a specific immune response where their intratumoral and peritumoral density as well as their functional status are correlated with clinical staging of the disease and with patients' survival. Under steady-state conditions, internalization of apoptotic cells by immature DCs designates a state of tolerance to self-antigens. Nevertheless, pathogens and necrotic cells interacting with pattern recognition receptors trigger downstream signaling pathways that evoke maturation of DCs, leading to the production of pro-inflammatory cytokines. These mature DCs are essential for T-cell priming and subsequent development of a specific immune response. Altered functions of DCs have an impact on the development of various disorders including autoimmune diseases and cancers. Herein, we focus on the checkpoints created throughout DCs antigen capturing and presentation to T cells, with subsequent development of either tolerance or immune response, with an emphasis on the role played by DCs in melanoma tumorigenesis and their therapeutic potential.