Dendritic cells as orchestrators of anticancer immunity and immunotherapy

Dendritic cells (DCs) are a heterogeneous group of antigen-presenting innate immune cells that regulate adaptive immunity, including against cancer. Therefore, understanding the precise activities of DCs in tumours and patients with cancer is important. The classification of DC subsets has historically been based on ontogeny; however, single-cell analyses are now additionally revealing a diversity of functional states of DCs in cancer. DCs can promote the activation of potent antitumour T cells and immune responses via numerous mechanisms, although they can also be hijacked by tumour-mediated factors to contribute to immune tolerance and cancer progression. Consequently, DC activities are often key determinants of the efficacy of immunotherapies, including immune-checkpoint inhibitors. Potentiating the antitumour functions of DCs or using them as tools to orchestrate short-term and long-term anticancer immunity has immense but as-yet underexploited therapeutic potential. In this Review, we outline the nature and emerging complexity of DC states as well as their functions in regulating adaptive immunity across different cancer types. We also describe how DCs are required for the success of current immunotherapies and explore the inherent potential of targeting DCs for cancer therapy. We focus on novel insights on DCs derived from patients with different cancers, single-cell studies of DCs and their relevance to therapeutic strategies. Dendritic cells (DCs) are antigen-presenting cells that function at the interface between innate and adaptive immunity, thereby acting as key mediators of antitumour immune responses and immunotherapy efficacy. In this Review, the authors outline the emerging complexity of intratumoural DC states that is being revealed through single-cell analyses as well as the contributions of different DC subsets to anticancer immunity and the activity of immune-checkpoint inhibitors. The authors also discuss advances in the development of DC-based cancer therapies and considerations for their potential combination with other anticancer therapies. Key points Dendritic cells (DCs) can induce adaptive anticancer immunity mainly via uptake and presentation of tumour-associated antigens, migration to lymph nodes and T cell priming, and recruitment and activation of tumour-infiltrating T cells. Intratumoural DCs originate from distinct ontogenic lineages and adopt heterogeneous functional states. The diversity of intratumoural DCs is generally c