不同表型肿瘤相关巨噬细胞在肿瘤进展中的作用

随着对肿瘤发生、侵袭和转移过程研究的不断深入，临床发现肿瘤相关巨噬细胞（tumor associated macrophage，TAM）在肿瘤微环境中扮演重要角色。由于经典活化的巨噬细胞（M1）/替代性活化的巨噬细胞（M2）理论过度简化了TAM在肿瘤微环境中的多种作用，目前临床大多根据表面蛋白表达的不同将TAM重新分为CD68+TAM、CD163+TAM、CD204+TAM、CD169+TAM、CCL18+TAM等。各型TAM表达的表面蛋白具有不同类型的配体并调控着不同的信号通路和细胞因子。因此，这些亚型的TAM具有促进或抑制肿瘤的类似作用，但其所牵涉的机制以及带来的临床表现均不相同。本文将就TAM各类表型对各类肿瘤的生长、转移、预后的影响及其临床关联进行综述。 

Role of different phenotype tumor-associated macrophages in tumor progression

Innate immune cells are highly represented in the tumor microenvironment, and among the most abundant of these are macrophages. However, macrophages are broadly categorized as "classically activated" pro-inflammatory M1 macrophages and "alternatively activated" anti-inflammatory M2 macrophages, which might be too simplified to describe the various phenotypes and functions of tumor-associated macrophages (TAMs). Most TAMs are now reclassified into CD68+TAM, CD163+TAM, CD204+TAM, CD169+TAM, and CCL18+TAM, among others, according to the different expression of surface proteins. These surface proteins have different types of ligands and regulate different signaling pathways and cytokines. Therefore, even if these subtypes of TAMs have similar effects of promoting or inhibiting tumors, the mechanisms involved and the induced clinical manifestations are different. In this paper, the effects of various phenotypes of TAMs on tumor growth, metastasis, prognosis, and clinical relevance are reviewed.