Abstract
Tumor-associated macrophages are one of the main populations of inflammatory cells in cancers that favor tumor cell growth and survival. Tumor-derived factors such as VEGF-A and CSF-1 recruit the macrophages in tumor micro environment and alter their phenotype in M1 to M2 or tumor-associated macrophages by secretion of several cytokines including IL-4, IL-13 and VEGF-A. In return tumor-associated macrophages released growth factors and cytokine that helps in cancer cell proliferation and metastasis. Tumor-associated macrophage secreted cytokines promotes the angiogenesis and lymphangiogenesis that assist tumor cell to metastasize in distant organs. Importantly, tumor-associated macrophages promote an immunosuppressive environment with the help of other immune cells in the tumor-bearing host that helps tumor to grow unchecked and unchallenged. In addition, tumor-associated macrophages induce resistance against cancer therapy and boost tumor regrowth after therapy. In this review, we discuss the role of tumor-associated macrophages in the pathobiology of cancer. Understanding of the crucial role of tumor-associated macrophages in cancer progression may help to assess potential therapeutic strategies.
Highlights
Cancer remains the most common cause of death in several countries, following cardiovascular diseases [1]
Tumor-associated Macrophages (TAMs) originate from circulating monocytes which infiltrated in Tumor Microenvironment (TME) and programmed by tumor-secreted factors such as vascular endothelial growth factor-A (VEGF-A) and colony-stimulating factor-1 (CSF-1) [13]
Macrophages induced production of ROS and nitric oxide (NO) induces all types of damages including the lethal DNA double strand breaks, which is evident by the increased chromosomal aberrations and ƔH2AX [140]
Summary
Cancer remains the most common cause of death in several countries, following cardiovascular diseases [1]. Growing body of evidence suggest that the Tumor Microenvironment (TME) play crucial role in development and progression of cancer [6,7,8]. Macrophages are the key component of innate immunity and perform multiple functions including tissue growth, tissue repair, homeostasis, and both inhibition or promotion of cell proliferation [11,12]. TME alters the macrophages to TAM phenotype and induce them toward Tumor-supportive M2-polarized macrophages [14,15,16]. We have discussed how TAM induced immunosuppression and therapy resistance help unchecked growth and survival of tumor cell. We have listed the tumor-derived factors responsible for macrophage polarization and TAM-derived factors that induce immune suppression and therapy resistance
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
