Background: Gastric cancer (GC) is one of the most common and aggressive types of cancer. Immune checkpoint inhibitors (ICIs) have proven effective in treating various types of cancer. The use of ICIs in GC patients is currently an area of ongoing research. The tumor microenvironment (TME) also seems to play a crucial role in cancer progression. Tumor-associated macrophages (TAMs) are the most abundant population in the TME. TAMs are capable of displaying programmed cell death protein 1 (PD-1) on their surface and can form a ligand with programmed death ligand 1 (PD-L1), which is found on the surface of cancer cells. Therefore, it is expected that TAMs may significantly influence the immune response related to immune checkpoint inhibitors (ICIs). Aim of the study: Understanding the role of TAMs and PD-1/PD-L1 networking in GC. Methods: A systematic review of published data was performed using MEDLINE (PubMed), Embase, and Cochrane databases. We retrieved articles investigating the co-existence of TAMs and PD-1 in GC and the prognosis of patients expressing high levels of PD-1+ TAMs. Results: Ten articles with a total of 2277 patients were included in the systematic review. The examined data suggest that the expression of PD-L1 has a positive correlation with the infiltration of TAMs and that patients who express high levels of PD-1+ TAMs may have a worse prognosis than those who express low levels of PD-1+ TAMs. Conclusions: TAMs play a pivotal role in the regulation of PD-1/PD-L1 networking and the progression of GC cells. Nevertheless, additional studies are needed to better define the role of TAMs and PD-1/PD-L1 networking in GC.
背景：胃癌是最常见且最具侵袭性的癌症类型之一。免疫检查点抑制剂已被证实对多种癌症治疗有效。目前，免疫检查点抑制剂在胃癌患者中的应用仍处于持续研究阶段。肿瘤微环境在癌症进展中也发挥着关键作用，其中肿瘤相关巨噬细胞是肿瘤微环境中数量最丰富的细胞群体。肿瘤相关巨噬细胞表面可表达程序性细胞死亡蛋白1，并能与癌细胞表面的程序性死亡配体1形成配体结合。因此，肿瘤相关巨噬细胞可能对免疫检查点抑制剂相关的免疫应答产生重要影响。 研究目的：探讨肿瘤相关巨噬细胞及PD-1/PD-L1信号网络在胃癌中的作用机制。 研究方法：通过MEDLINE（PubMed）、Embase和Cochrane数据库对已发表文献进行系统性综述。我们检索了关于胃癌中肿瘤相关巨噬细胞与PD-1共表达的研究，以及高表达PD-1阳性肿瘤相关巨噬细胞患者预后的相关文献。 研究结果：共纳入10篇文献，涉及2277例患者。分析数据显示，PD-L1表达水平与肿瘤相关巨噬细胞浸润呈正相关，且高表达PD-1阳性肿瘤相关巨噬细胞的患者预后较低表达者更差。 结论：肿瘤相关巨噬细胞在调控PD-1/PD-L1信号网络及胃癌细胞进展中发挥关键作用。然而，仍需进一步研究以明确肿瘤相关巨噬细胞及PD-1/PD-L1信号网络在胃癌中的具体作用机制。
TAMs and PD-1 Networking in Gastric Cancer: A Review of the Literature
肿瘤(癌症)患者之家