While highlighting the complexity and heterogeneity of tumor immune microenvironments, the application of single-cell analyses in human cancers has identified recurrent subsets of tumor-associated macrophages (TAMs). Among these, interleukin (IL)-1β+ TAMs – cells with high levels of expression of inflammatory response and tissue repair genes, but with limited capacity to stimulate cytotoxic immunity – are emerging as key drivers of pathogenic inflammation in cancer. In this review we discuss recent literature defining the phenotypical, molecular, and functional properties of IL-1β+ TAMs, as well as their temporal dynamics and spatial organization. Elucidating the biology of these cells across tumor initiation, progression, metastasis, and therapy could inform the design and interpretation of clinical trials targeting IL-1β and/or other inflammatory factors in cancer immunotherapy.

While highlighting the complexity and heterogeneity of tumor immune microenvironments, the application of single-cell analyses in human cancers has identified recurrent subsets of tumor-associated mac...