Fig. 4
From: The roles of tissue resident macrophages in health and cancer
Dynamic interplay between pro- and antitumorigenic microglia and tumor cells in primary and metastatic cancers. In primary tumors, microglia enhance the proliferation and migration of cancer cells in both in vitro and in vivo settings by releasing TGF-β, EGF, and STI1. Cancer cells induce microglia to secrete and release IL-6 through the CCL2/CCR2 axis, thereby promoting glioma invasion。During cancer metastasis, tumor cells stimulate the JAK2/STAT3 signaling pathway in microglia by secreting IL-6 and promote tumor cell migration through the secretion of ANXA1, which reduces microglial migration and activates the STAT3. Elevated expression of TGF-β in microglia fosters tolerance towards cancer cells by anti-tumor CTL. CpG-C, inhibits brain metastasis by activating microglia, while the CD47-SIRPα axis acts as a crucial innate immune checkpoint suppressing phagocytic activity in myeloid cells