A promising road in colorectal cancer treatment: personalized immunotherapy based on molecular and immune classification system

Immunotherapy has increasingly proven to be a key treatment modality that can make a significant impact on the lives of many cancer patients. In particular, immune checkpoint inhibitors targeting the programmed cell death protein 1 (PD-1) pathway have led to remarkable clinical benefits in various cancers, including melanoma and lung cancer, and active investigations are ongoing to expand their therapeutic utility in other cancer types (1). In fact, several clinical trials have revealed a link between high somatic mutation prevalence and the clinical success in PD-1 axis blockade. Considering that colorectal cancers (CRC) are known to have very high rates of somatic mutations in comparison to other solid cancers (2), the potential of immunotherapeutic agents in treating patients with CRC is encouraging (3,4). However, in harnessing the full potential of immunotherapy, several key questions need to be addressed: which patients are to be treated in order to maximize therapeutic benefits; how would immunotherapy be combined with other treatment modalities; and how would optimal biological dosing be determined with minimal toxicity as well as cost-effectiveness (5)