结直肠癌免疫微环境中肿瘤相关巨噬细胞的作用

结直肠癌（colorectal cancer，CRC）的发生、发展不仅与肿瘤细胞本身的特性相关，也与肿瘤微环境（tumor microenvironment，TME）密切相关。肿瘤细胞及其微环境通过分泌多种细胞因子，将循环血液中的单核细胞招募至TME并使其极化为肿瘤相关巨噬细胞（tumor-associated macrophages，TAMs）。作为TME中最丰富的免疫细胞之一，TAMs的功能和特点与M2型巨噬细胞相似，TAMs主要具有刺激肿瘤细胞增殖、血管生成、基质重塑和促进肿瘤细胞侵袭及转移等作用。在多数肿瘤中，TAMs主要发挥促肿瘤作用并与患者的不良预后相关；但在CRC中，TAMs的作用仍存争议。本文主要就CRC免疫微环境中TAMs的作用及其机制进行综述，以展示TAMs对CRC患者的病程进展及预后的影响并探讨TAMs作为CRC免疫治疗靶点的可行性。 

Role of tumor-associated macrophages in the immune microenvironment of colorectal cancer

The occurrence and development of colorectal cancer (CRC) are not only related to the characteristics of the tumor cells but also to the tumor microenvironment (TME). Tumor cells and the TME secrete a variety of cytokines to recruit monocytes in the circulating blood to the TME and polarize them into tumor-associated macrophages (TAMs). As one of the most abundant immune cells in the TME, TAMs have functions and characteristics similar to those of M2 macrophages. They mainly stimulate tumor cell proliferation, angiogenesis, and matrix remodeling and promote tumor cell invasion and metastasis. Studies have shown that in most tumors, TAMs mainly have a tumor-promoting effect and are related to the poor prognosis of patients; however, in CRC, the role of TAMs remains controversial. This article reviews the role and mechanisms of TAMs in the TME of CRC to examine the influence of TAMs on the progression and prognosis of CRC and to explore the feasibility of TAMs as targets for CRC immunotherapy.