Figure 3.

Differentiation of tumor associated macrophages with distinct functions. Tumor associated macrophages (TAMs) are both embryonic and monocyte origins. Monocytes derived TAMs highly express genes related to inflammatory and immunosuppression; While embryo-derived TAMs highly express genes related to tumorigenesis, metastasis and angiogenesis. FCN1 ⁺ and C1Q ⁺ TAM subpopulations are derived from peripheral blood monocytes, whereas SPP1 ⁺ and CCL18⁺TAMs are derived from tissue-resident macrophages (pre-SPP1⁺ macrophages from embryo and monocyte derived macrophages). Differentiation of TAMs from peripheral blood monocytes to C1Q ⁺ macrophages includes monocytes, FCN1+ macrophages, and pre-C1Q ⁺ and mature C1Q ⁺ macrophages. Differentiation of TAMs from tissue-resident macrophages into CCL18 ⁺ macrophages occurs via pre-SPP1 ⁺ and mature SPP1 ⁺. Furthermore, mature C1Q ⁺ and SPP1 ⁺ macrophages can be divided into different populations with distinct functions. iDC, inflammatory dendritic cells; tDC, tolerant dendritic cells; MDSCs, myeloid-derived suppressor cells; NK, natural killer cells. Dotted line arrow: predicted pathway based on gene expression.