Colorectal cancer can be categorized into two major molecular subtypes according to the status of their DNA proofreading and repair machinery. The DNA repair status of tumor cells plays a major role in shaping the immune landscape of tumors and in determining the clinical response of colorectal cancer patients to immune checkpoint blockade therapies. Colorectal cancers that develop in a context of DNA mismatch repair or polymerase proofreading deficiency are generally conspicuously infiltrated by effector memory T cells and are associated with an improved clinical prognosis relative to their replication repair-proficient counterpart. While mismatch repair-deficient colorectal cancers, and most likely POLE and POLD1-mutated cancers, are amenable to immune checkpoint blockade therapies, the promise of immunotherapy still remains unfulfilled for for the majority of colorectal cancer patients. This review focusses on the role of the immune system in the tumorigenesis and clinical behavior of colorectal cancer. Furthermore, we discuss how latest advances in the fields of genomics and oncoimmunology may pave the way to broaden the scope of immunotherapy for this disease.

大肠癌可根据其DNA校对和修复机制的状态分为两种主要的分子亚型。肿瘤细胞的DNA修复状态在塑造肿瘤的免疫格局以及确定结直肠癌患者对免疫检查点封锁疗法的临床反应中起着重要作用。在DNA错配修复或聚合酶校对缺乏的情况下发展的大肠癌通常明显被效应器记忆T细胞浸润，并且相对于其复制修复能力强的癌伴，其临床预后得到改善。错配修复缺陷的大肠癌，最有可能是POLE和POLD1突变的癌症适合进行免疫检查点封锁疗法，对于大多数结直肠癌患者来说，免疫疗法的前景仍未实现。这篇综述着重于免疫系统在结直肠癌的发生和临床行为中的作用。此外，我们讨论了基因组学和肿瘤免疫学领域的最新进展如何为扩大该疾病的免疫疗法范围铺平道路。