LAUSR

Tumor-associated macrophages (TAMs), in close proximity or within tumor masses, are a type of cell belonging to the macrophage lineage that constantly shift their functional states in response to changes in the tumor microenvironment (TME). The percentage of macrophages in human malignancies is reported to be between 10% and 65% in cancer surgical specimens, representing a prominent cellular component in TMEs. These cells dampen inflammation, promote tissue remodeling and tumor progression, and their density is associated with adverse outcomes and shorter survival in several cancer types. TAMs have been proposed to originate from blood monocytes, attracted by recruitment signals produced by tumor cells, instructed by TMEs, and eventually developing into potent tumor-supporting cell populations. Although great efforts being made toward TAM-centered research, there is still a lack of systemic understanding of this complex cell population. In this review, we summarize how TAMs transform, with particular focus on recruitment and function adaptivity, and try to provide an insight into the progression of TAMs. Finally, we will review some emerging TAM-related therapies for cancer treatment.