Figure 1.

The cancer-immunity cycle. The cancer-immunity cycle is a series of steps through which the immune system passes in order to recognize and attack cancer cells. The cycle includes seven stages, starting with the release of cancer-cell antigens and ending with the destruction of cancer cells by T cells. The first stage involves the release of antigens from dying cancer cells. These antigens are then taken up by dendritic cells, which present them to T cells in the lymph nodes. In the second stage, activated T cells migrate to the tumor site and infiltrate the tumor. The third stage involves recognition of cancer cells by T cells, and the fourth stage involves the activation of T cells to recognize and kill cancer cells. In the fifth stage, T cells work to penetrate the tumor and release cytokines that recruit immune cells to the tumor site. In the sixth stage, immune cells, including macrophages and dendritic cells, infiltrate the tumor and destroy cancer cells. Finally, in the seventh stage, the immune system remembers the cancer cells, creating a lasting immune response that can protect against future cancer development.