MRC1 and neoplasm: M1-like branches are classically activated macrophages in response to IFN-γ with Toll-like receptor engagement and are characterized by their cytotoxity and by high expression of IL-12, CD86, CXCL9, CXCL10, IL-23, IL-6, and TRAIL.42, 43 In contrast, M2-like branches are alternatively activated macrophages in response to IL-4 and IL-13 and are characterized by high expression of CD206, arginase-1 (ARG1), and IL-10.44 In general, tumor-associated macrophages (TAMs) exhibit M2-like properties and promote tumor progression.