The Role of Tumor-Associated Macrophages in Leukemia

Abstract

In addition to intrinsic factors, leukemia cell growth is influenced by the surrounding nonhematopoietic cells in the leukemic microenvironment, including fibroblasts, mesenchymal stem cells, vascular cells, and various immune cells. Despite the fact that macrophages are an important component of human innate immunity, tumor-associated macrophages (TAMs) have long been considered as an accomplice promoting tumor growth and metastasis. TAMs are activated by an abnormal malignant microenvironment, polarizing into a specific phenotype and participating in tumor progression. TAMs that exist in the microenvironment of different types of leukemia are called leukemia-associated macrophages (LAMs), which are reported to be associated with the progression of leukemia. This review describes the role of LAMs in different leukemia subtypes.

CSC Radioresistance: A Therapeutic Challenge to Improve Radiotherapy Effectiveness in Cancer

“…Additionally, tumor cells in the TME are able to control the immune response by increasing the amount of myeloid-derived suppressor cells, tumor-associated neutrophils (TANs), dendritic cells, and tumor-associated macrophages (TAMs) [ 111 ]. TAMs, like CAFs, participate in tumorigenesis by promoting genetic instability and tumor growth, nurturing CSCs, paving the way to metastasis and suppressing the protective adaptive immunity [ 122 , 123 ]. TAMs can perform different functions by differentiating into different subtypes through a process called polarization, which involves bidirectional interaction between the tumor microenvironment and macrophages.…”

“…TAMs can perform different functions by differentiating into different subtypes through a process called polarization, which involves bidirectional interaction between the tumor microenvironment and macrophages. These TAM subtypes are classically activated macrophages (M1) and alternatively activated macrophages (M2) [ 122 ]. M1 macrophages have antitumor effects, produce pro-inflammatory factors, and participate in the immune defense against external pathogens.…”

“…M1 macrophages have antitumor effects, produce pro-inflammatory factors, and participate in the immune defense against external pathogens. Instead, M2 are considered the true TAMs and promote angiogenesis, immunosuppression, and metastasis [ 30 , 109 , 122 ].…”

CtBP1 promotes tumour‐associated macrophage infiltration and progression in non–small‐cell lung cancer

“…TAMs promote immune suppression angiogenesis, and metastasis in cancers via the release of chemokines, cytokines, matrix metalloproteases and growth factors. Enhanced infiltration of TAM is related to a poor prognosis in NSCLC 12,13 . Earlier research has revealed that STAT‐3, NF‐κB (nuclear factor‐κB) and hypoxia‐inducible factor‐1 signalling pathways play a role in recruitment and polarization of TAMs 14,15 .…”

“…Enhanced infiltration of TAM is related to a poor prognosis in NSCLC. 12,13 Earlier research has revealed that STAT-3, NF-κB (nuclear factor-κB) and hypoxia-inducible factor-1 signalling pathways play a role in recruitment and polarization of TAMs. 14,15 However, the process involved in TAMs infiltration of the NSCLC cells has not been well elucidated.…”