关键词: 结直肠癌, 微卫星稳定, 微卫星高度不稳定, 免疫治疗

Abstract: In recent years, research on immune therapy for colorectal cancer with microsatellite stability (MSS) and microsatellite instability-high (MSI-H) has been continuously emerging. Studies such as KEYNOTE-177 and CheckMate-142 provide important clinical data support for immunotherapy of MSS and MSI-H colorectal cancer. MSI-H type colorectal cancer is not sensitive to conventional chemotherapy and often has a poor prognosis. However, due to the presence of a high mutation burden and new antigens, it responds well to immune checkpoint inhibitors such as programmed death receptor 1 (PD-1) inhibitors and cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) inhibitors. However, MSS-type colorectal cancer has a lower mutation burden and weaker immunogenicity, resulting in a poorer response to immunotherapy. At present, by exploring combination therapy and improving immune regulation strategies, such as targeting immunosuppressive cells or factors in the tumor microenvironment, the immunotherapeutic effect of MSS-type colorectal cancer can be improved and effective biomarkers can be found. In addition, some studies have also explored the application of immunotherapy in neoadjuvant therapy for colorectal cancer and its combination with other treatment methods. These studies not only enrich the understanding of immunotherapy for MSS and MSI-H colorectal cancer but also provide more treatment options for clinical practice.

Key words: colorectal cancer, microsatellite stable, microsatellite instability-high, immunotherapy