Tumor‑associated macrophages: Role in the pathological process of tumorigenesis and prospective therapeutic use (Review)

Abstract

The aim of the present study was to evaluate the current body of knowledge regarding tumor-associated macrophages (TAMs) and their potential use in antitumor therapy, based on their role in the pathological process of tumorigenesis. For this purpose, a critical analysis of published data and summarization of the findings available from original studies, focusing on the role of TAMs in the pathological process, and their potential therapeutic application was performed. Promising key avenues of research were identified in this field. The following issues seem the most promising and thus worth further investigation: i) The process of M1/M2 macrophage polarization, macrophage characteristics at intermediate polarization steps and their role in the tumor process; ii) determining the conditions necessary for transitions between the M1 and M2 macrophage phenotypes and the role of signals from the microenvironment in this process; iii) cause-and-effect associations between the quantity and quality of macrophages, and the prognosis and outcome of the pathological process; iv) modulation of macrophages and stimulation of their phagocytic activity with drugs; v) targeted vector-based systems for drug delivery to macrophages; and vi) targeted drug delivery systems with macrophages as carriers, thus potentially combining chemotherapy and immunotherapy.

Macrophage subtypes inhibit breast cancer proliferation in culture

“…Given that macrophage infiltration correlates with tumor grade, these results suggest that early in tumorigenesis (Mahmoud et al ., 2012; Yuan et al ., 2019; Jamiyan et al ., 2020), cancer cells begin to proliferate in the absence of stromal cells. Indeed, macrophage infiltration is still an early step in breast cancer tumorigenesis (Zhukova et al ., 2020; Zhu et al ., 2021), but we would argue that whether tumor growth is a direct effect of pro-tumor macrophages or a consequence of the function of pro-tumor macrophages on other stromal cells is unclear. Tumor-associated macrophages have been shown to promote tumor angiogenesis which brings nutrients into the tumor, fueling tumor growth (Riabov et al ., 2014; Fu et al ., 2020).…”

SENP1‐KLF4 signalling regulates LPS‐induced macrophage M1 polarization

“…Macrophages, as a result of their phenotypic variability and functional diversity, play roles in the human body, including tumour inhibition via multiple molecular mechanisms [28][29][30]. Macrophage polarization is a very delicate and complex process.…”

Immunopharmacological Properties of Methacrylic Acid Polymers as Potential Polymeric Carrier Constituents of Anticancer Drugs

“…The pro-oncogenic effects most commonly mentioned for IL-10 are that IL-10 reduces the antitumor immune response in the tumor microenvironment, thus helping tumor cells to evade the effects of immune cells and stimulates angiogenesis [49][50][51]. Stimulation of natural killer cells and inhibition of reactive oxygen species are noteworthy among the antitumor effects of the cytokine [51].…”