Signature Gene Mutations in Colorectal Cancer: Potential Neoantigens for Cancer Vaccines

Colorectal cancer (CRC), the third most common cancer worldwide, is one of the deadliest cancers. CRC is known as a cold tumor, characterized by a low immune response that makes it difficult for immune cells to infiltrate and exhibits strong resistance to immunotherapy with checkpoint inhibition. This restricted response is largely attributed to signature gene mutations including mismatch repair (MMR) genes, KRAS, BRAF, APC, and TP53, which are also the main oncogenes in CRC. Mutated signature genes continuously upregulate abnormal signaling pathways, leading to excessive proliferation, cancer progression, and metastasis. Furthermore, it reorganizes the tumor microenvironment (TME) by recruiting immunosuppressive cells. However, the mutation can produce neoantigens that can provoke an immune response, making it a potential target for immunotherapy. In particular, cancer vaccines that leverage the strong neoantigenic properties of these mutations are considered promising for overcoming immune resistance and eliciting anti-tumor responses. In this review, we will describe signature gene mutations in CRC and focus on cancer vaccines targeting these mutations as potential therapies for CRC.