The therapy used to treat cancer works by stimulating the immune system to fight back against the cancer disease. One of the main therapies for cancer is cellular immunotherapy, in which dendritic cell therapy provokes anti-tumour responses. The only cellular cancer therapy based on dendritic cells that has been approved is sipuleucel-T. The other method of inducing the dendritic cells that are present in the tumour antigens is by vaccination with autologous tumour lysates or by using short peptides. Sometimes these peptides also include proteins and other chemicals to attract the dendritic cells, like granulocyte macrophage colony-stimulating factor. Dendritic cells can be activated by in vivo expressing GM-CSF in tumour cells. This can be accomplished by genetically modifying tumour cells to produce GM-CSF or infecting tumour cells with an oncolytic virus that expresses GM-CSF. Another method is to remove dendritic cells from a patient's blood and activate them outside the body. Dendritic cells respond to tumour antigens, which can be a single tumour-specific peptide or protein or a tumour cell lysate. These cells are infused and provoke an immune response. In dendritic cell therapies, antibodies have been used that bind to the receptors present on the surfaces of dendritic cells. Antigens can be added to antibodies to induce dendritic cell maturation and provide tumour immunity. In immunotherapy, the dendritic cell-NK cell interface is also important. New dendritic cell-based vaccination strategies should include NK cell-stimulating potency. It is critical to incorporate NK cell monitoring as an outcome measure in antitumor DC-based clinical trials. The drug sipuleucel-T (Provenge) was approved for the treatment of asymptomatic or mildly symptomatic metastatic castration-resistant prostate cancer. The treatment entails removing antigen-presenting cells from the blood via leukapheresis, growing them with the fusion protein PA2024 made of GM-CSF and prostate-specific prostatic acid phosphatase (PAP), and reinfusing them. This procedure is carried out three times.