[Application of immune combination therapy in MSS/pMMR-type colorectal cancer: current status and future...

In recent years, immune checkpoint inhibitors (ICIs) have been widely used in malignant solid tumors with remarkable efficacy. However, in colorectal cancer (CRC), ICIs have shown significant therapeutic effects only in patients with highly microsatellite unstable/mismatch repair-deficient metastatic CRC and these patients are only a minority of all CRC patients. In contrast, the majority of patients, those with microsatellite stable (MSS)/mismatch repair-complete (pMMR)-type metastatic CRC, could hardly benefit from ICI monotherapies, and immune combination therapies have become the key to solveing this clinical challenge. This article introduces the common patterns and possible mechanisms of immune-combination therapies for MSS/pMMR-type CRC, the exploration and progress made in the application of immune-combination therapies, as well as the possible predictive markers of efficacy of immune therapies. The prospects and directions of ICIs in the treatment of MSS/pMMR-type CRC are also discussed.