Immunotherapy has become a major weapon against the war on cancer. This has culminated from decades of seminal work that led to the discovery of innovative approaches to drive adaptive immunity. Notably, was the discovery of immune checkpoint inhibitory receptors on T cells, and the subsequent development of monoclonal antibodies that target those receptors, known as immune checkpoint inhibitors (ICIs). Blocking those receptors using ICIs leads to sustained effector function, which has translated to enhanced antitumor responses across multiple human cancer types. However, these treatments are effective in subsets of patients, implicating significant barriers limiting therapeutic potential. While numerous mechanisms may hinder immunotherapy potency, one prominent mechanism is the production of myeloid-derived suppressor cells (MDSCs). MDSCs comprise monocytic and granulocytic cell types and mediate pro-tumorigenic and immune suppressive activities. Here, we summarize several pathways by which MDSCs arise in cancer, providing a conceptual framework for identifying unique combination therapeutic interventions.

免疫疗法已成为对抗癌症的主要武器。数十年的开创性工作促成了这一点，这些工作导致发现了驱动适应性免疫的创新方法。值得注意的是，在 T 细胞上发现了免疫检查点抑制受体，随后开发了针对这些受体的单克隆抗体，称为免疫检查点抑制剂 (ICI)。使用 ICI 阻断这些受体会导致持续的效应器功能，这已转化为增强多种人类癌症类型的抗肿瘤反应。然而，这些治疗对部分患者有效，这意味着限制治疗潜力的重大障碍。虽然许多机制可能会阻碍免疫治疗的效力，但一个突出的机制是髓源抑制细胞 (MDSC) 的产生。MDSCs 包括单核细胞和粒细胞类型，并介导促肿瘤和免疫抑制活性。在这里，我们总结了 MDSC 在癌症中出现的几种途径，为识别独特的联合治疗干预措施提供了一个概念框架。