Open Access

Targeting tumor‑associated macrophages in the tumor microenvironment (Review)

  • Authors:
    • Kaiwen Zhou
    • Tan Cheng
    • Jinyue Zhan
    • Xuan Peng
    • Yue  Zhang
    • Jianpei Wen
    • Xiaoman Chen
    • Muying Ying
  • View Affiliations

  • Published online on: September 14, 2020     https://doi.org/10.3892/ol.2020.12097
  • Article Number: 234
  • Copyright: © Zhou et al. This is an open access article distributed under the terms of Creative Commons Attribution License.

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Abstract

Tumor‑associated macrophages (TAMs) are the most abundant population type of tumor‑infiltrating immune cells found in the tumor microenvironment (TME), and are evolutionarily associated with microvessel density in tumor tissues. TAMs can be broadly divided into M1‑like and M2‑like TAMs, which demonstrate antitumor and pro‑tumor activity in the TME, respectively. Studies have indicated that: i) The predominate presence of M2‑like TAMs in the TME can result in tumor immunosuppression and chemoresistance; ii) the ratio of M1‑like to M2‑like TAMs in the TME is positively correlated with better long‑term prognosis of patients with cancer; iii) epigenetic silencing, preventing the secretion of M1‑like TAM‑associated molecules, is an important immune evasion mechanism during tumor progression; and iv) the transformation from M2‑like to M1‑like TAMs following exposure to specific conditions can result in tumor regression. The present study discusses the molecular events underlying the recruitment of macrophages and their polarization into M1‑like or M2‑like TAMs, and their differential roles in angiogenesis, angiostasis, invasion, metastasis and immune activity in the TME. This insight may inform the improved design of TAM‑targeted cancer immunotherapy. Some of these therapeutic strategies show promising effects; however, challenges remain.
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November-2020
Volume 20 Issue 5

Print ISSN: 1792-1074
Online ISSN:1792-1082

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Copy and paste a formatted citation
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Spandidos Publications style
Zhou K, Cheng T, Zhan J, Peng X, Zhang Y, Wen J, Chen X and Ying M: Targeting tumor‑associated macrophages in the tumor microenvironment (Review). Oncol Lett 20: 234, 2020.
APA
Zhou, K., Cheng, T., Zhan, J., Peng, X., Zhang, Y., Wen, J. ... Ying, M. (2020). Targeting tumor‑associated macrophages in the tumor microenvironment (Review). Oncology Letters, 20, 234. https://doi.org/10.3892/ol.2020.12097
MLA
Zhou, K., Cheng, T., Zhan, J., Peng, X., Zhang, Y., Wen, J., Chen, X., Ying, M."Targeting tumor‑associated macrophages in the tumor microenvironment (Review)". Oncology Letters 20.5 (2020): 234.
Chicago
Zhou, K., Cheng, T., Zhan, J., Peng, X., Zhang, Y., Wen, J., Chen, X., Ying, M."Targeting tumor‑associated macrophages in the tumor microenvironment (Review)". Oncology Letters 20, no. 5 (2020): 234. https://doi.org/10.3892/ol.2020.12097