Tumor associated macrophages (TAMs) are the most frequent immune cells within tumor microenvironment (TME). There is growing evidence that TAMs are involved in tumor progression via multiple mechanisms. TAMs create an immunosuppressive TME by producing growth factors, chemokines, and cytokines which modulate recruitment of immune cells and inhibit anti-tumor responses. They also serve as angiogenesis promoting cells by production of pro-angiogenic factors and matrix metalloproteinases (MMPs) and vascular constructing which guarantee supplying oxygen and nutrients to solid tumor cells. Furthermore, TAMs play important functions in tumor metastasis through contributing to invasion, extravasation, survival, intravasation, and colonization of tumor cells. In this review, we summarized macrophage classification, TAMs polarization, and mechanisms underlying TAM-promoting angiogenesis and metastasis.

中文翻译：

---

肿瘤相关巨噬细胞在肿瘤血管生成和转移中的作用。

肿瘤相关巨噬细胞（TAM）是肿瘤微环境（TME）中最常见的免疫细胞。越来越多的证据表明，TAMs通过多种机制参与了肿瘤的发展。TAM通过产生生长因子，趋化因子和细胞因子来调节免疫细胞的募集并抑制抗肿瘤反应，从而产生一种免疫抑制性TME。它们还通过促血管生成因子和基质金属蛋白酶（MMP）的产生以及血管构建来作为促进血管生成的细胞，保证向实体肿瘤细胞供应氧气和营养。此外，TAM通过促进肿瘤细胞的侵袭，外渗，存活，内渗和定植，在肿瘤转移中起重要作用。在这篇综述中，我们总结了巨噬细胞分类，TAM极化，