Tumor Infiltrating Lymphocyte (TIL) therapy is reportedly showing promise as an immunotherapy treatment.
What the heck is a tumor infiltrating lymphocyte? It’s pretty much what it sounds like, a white blood cell that has managed to make it’s way into a cancer tumor.
Why is that interesting? Well, in part because many cancers are slick operators, able to avoid much of the body’s normal immune response. Researchers have found, however, that tumors may contain at least some lymphocytes that have been activated and are busy battling the cancerous cells. Unfortunately, they’re usually in the minority and fighting a losing battle. Or they may suffer down regulation as a result of the tumor cells sending false “cease and desist” orders. (Cancer really is a tricky son of a gun!) But ….
What if you could build an army of those smart immune cells – the ones that are able to recognize the cancer as an invading disease? Then you’d have a host of immune cells attacking and potentially eradicating the tumor!
The idea is similar to CAR-T treatment in which a patient’s t-cells are harvested, modified to target a specific antigen on the cancer cells, reproduced in the millions, and infused back into the patient. Smart t-cells programmed to kill a cancer! The primary differences between TIL therapy and CAR-T are that the soldiers recruited are harvested from a tumor rather than the peripheral blood and they’re already programmed to attack the cancer. In TIL therapy, those lymphocytes can be further enhanced to recognize still more markers specific to the tumor cells.
The process includes a tumor biopsy to harvest the necessary lymphocytes and a chemo prep in advance of the infusion to ensure a patient’s immune system doesn’t attack the newly introduced cells – i.e. no civil war, just war on the disease. There’s also some medication after the procedure to stimulate TIL anti-tumor activity.