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Fig. 2 | Journal of Hematology & Oncology

Fig. 2

From: Aging microenvironment and antitumor immunity for geriatric oncology: the landscape and future implications

Fig. 2

Differences between young and aged TME and senescence-induced factors. One of the critical factors involved in age-related pathologies is immunosenescence defined as a significant decline in overall immune function. The subpopulations of effector immune cells including T cells, NK cells, macrophages, and DCs exhibit a dramatic decrease in cytotoxic activity during the senescence. Age-related immunosenescence plays a key role in promoting tumor formation and accumulation of SASP-secreting cells; the SASP-related decreases in effector immune cell function can also induce tissue-specific switching toward more immunosuppressive cell populations. In the elderly, immunosuppressive MDSCs and Tregs are significantly increased in aged tissue and blood; besides, neutrophils and macrophages appear to switch phenotypically toward immunosuppressive N2 and M2 states, both of which have been shown to promote tumorigenesis of various cancer types, while more direct evidence on the involvement in age-related tumorigenesis is warranted. The accumulation of SASP stromal components results in inflammaging that disrupts acute inflammatory response toward malignant tissue, induces infiltration of immunosuppressive MDSCs and Tregs, and improves secretion of anti-inflammatory components such as cytokines, chemokines, and inflamma-microRNAs. Inflammaging seems to downregulate antitumor activity in aged tissues. NK cells, natural killer cells; DCs, dendritic cells; SASP, senescence-associated secretory phenotype; MDSCs, myeloid-derived suppressor cells; Tregs, regulatory T cells; ARG1, arginase 1; CRP, C-reactive protein; ECM, extracellular matrix; GM-CSF, granulocyte–macrophage colony-stimulating factor; IFN-γ, interferon-γ; IL, interleukin; ROS, reactive oxygen species; TGF-β, transforming growth factor-β; TNF, tumor necrosis factor (Mainly from https://doi.org/10.1038/s41568-019-0222-9 [3])

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