A review on cancer vaccines: Current developments and future prospects

Tumour immunotherapy has made tremendous progress in the past decades, with numerous studies entering the clinical evaluation. The cancer vaccine is considered a promising therapeutic strategy in the immunotherapy of solid tumours. Cancer vaccines stimulate antitumor immunity using tumour antigens, which can be delivered as whole cells, peptides, nucleic acids, etc. An ideal cancer vaccine would be able to overcome tumour immunosuppression and induce both humoral and cellular immunity. The use of cancer vaccines is considered a promising therapeutic strategy in clinical oncology, which is achieved by stimulating anti-tumour immunity with tumour antigens delivered in the form of cells, peptides, viruses and nucleic acids. The ideal cancer vaccine has many advantages, including low toxicity, specificity, and induction of persistent immune memory to overcome tumour heterogeneity and reverse the immunosuppressive microenvironment. Cancer treatment is done by surgery,chemotherapy,radiation therapy. These treatments may cure early-stage cancer, but are often ineffective in treating advanced or recurrent cancer. Basic and clinical studies of the tumour microenvironment, which consists of cancer cells, stromal cells, and  immune cells, have demonstrated the important role of antitumor immunity in cancer development and progression. Cancer immunotherapy has been proposed as a fourth cancer treatment option. In particular, the clinical application of immune checkpoint inhibitors, such as anti-CTLA-4 and anti-PD-1/PD-L1 antibodies, to various types of cancer represents a  major advance in cancer treatment. Indeed, several issues remain to be solved to improve their clinical efficacy; these include low cancer cell antigenicity and poor infiltration and/or accumulation of immune cells in the cancer microenvironment.