Tumor infiltrating lymphocytes (TILs) are a type of immune cell that is found within a tumor. Neoantigens are a type of antigen that is unique to cancer cells and is not found on normal, healthy cells. They are generated as a result of mutations that occur in cancer cells and can be recognized by the immune system as foreign. TILs are thought to play a role in the immune response to neoantigens, as they are able to recognize and attack cancer cells that express these unique antigens.
The ability of TILs to recognize neoantigens is thought to be important in the effectiveness of cancer immunotherapies, such as checkpoint inhibitors. These therapies work by releasing the brakes on the immune system, allowing it to more effectively attack cancer cells. The presence of TILs may indicate that a patient's immune system is already actively attacking the tumor, making them more likely to respond to immunotherapy.
TILs have also been shown to be associated with a more favorable prognosis in some cancer types, including melanoma and breast cancer. In these cases, the presence of TILs may indicate that the immune system is actively trying to eliminate the cancer cells, leading to better outcomes.