title: The emerging understanding of myeloid cells as partners and targets in tumor rejection.
abstract: Myeloid cells are the most prominent among cells capable of presenting tumor-derived antigens to T cells and thereby maintaining the latter in an activated state. Myeloid populations of the tumor microenvironment prominently include monocytes and neutrophils (sometimes loosely grouped as myeloid-derived suppressor cells), macrophages, and dendritic cells. Although intratumoral myeloid populations, as a whole, have long been considered nonstimulatory or suppressive, it has only recently been appreciated that not all tumor-infiltrating myeloid cells are made equal. Because of advances in high-dimensional flow cytometry as well as more robust transcriptional profiling, we now also understand that the subsets of the tumor-myeloid compartment are far more diverse and notably even contain a rare population of stimulatory dendritic cells. As all of these myeloid populations represent major T-cell-interacting partners for incoming tumor-reactive cytotoxic T lymphocytes, understanding the distinctions in their lineage and function reveals and guides numerous therapeutic avenues targeting these antigen-presenting cells. In this Cancer Immunology at the Crossroads overview, we review the recent progress in this rapidly evolving field and advance the hypothesis that the antigen-presenting compartment within tumor microenvironments may contain significant numbers of potent allies to be leveraged for immune-based tumor clearance.
authors.affiliation: Department of Pathology, University of California at San Francisco, San Francisco, California.
authors.forename: Miranda L
authors.initials: ML
authors.lastname: Broz
authors.affiliation: Department of Pathology, University of California at San Francisco, San Francisco, California. matthew.krummel@ucsf.edu.
authors.forename: Matthew F
authors.initials: MF
authors.lastname: Krummel
mesh_terms: D017951:Antigen Presentation / Q000276:immunology; D000938:Antigen-Presenting Cells / Q000276:immunology; D000951:Antigens, Neoplasm / Q000276:immunology; D016207:Cytokines / Q000276:immunology; D006801:Humans; D008213:Lymphocyte Activation / Q000276:immunology; D016246:Lymphocytes, Tumor-Infiltrating / Q000276:immunology; D022423:Myeloid Cells / Q000276:immunology*; D009369:Neoplasms / Q000276:immunology* / Q000628:therapy; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D059016:Tumor Microenvironment / Q000276:immunology
chemical_list: D000951:Antigens, Neoplasm; D016207:Cytokines
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