Combating colorectal cancer with immunotherapy: Where are we?

Despite incessant advancement in the therapeutic regimens against colorectal cancer (CRC), treatment failure, metastasis and serious side effects associated with the available therapeutic options demand specific targeted therapies that could help in improving the survival rate with significantly less toxicity, fewer untoward effects and improved efficacy. In-depth studies highlighted the potential of CRC to be immune-responsive, thereby opening a new door in the development of strategies to combat CRC. Immunotherapy has attracted a myriad of researchers with a hope that it could potentially increase the efficacy of the treatment regimens in parallel to the reduction of toxicity. Colorectal tumors undergo immune evasion, suppressing patients' immunity and making them susceptible to infections. Therefore, a viable option could be stimulating a patient's own immune system with the help of immune modulators to fight against CRC. This review briefly discusses the immune responsiveness of CRC as well as tumor-associated antigens in CRC, and highlights the current endeavors of the scientific community in the field of immune modulators against CRC that are under development including varied types of vaccines, checkpoint inhibitors and adoptive T-cell therapy.