tumor-infiltrating lymphocyte
(TOO-mer-IN-fil-TRAY-ting LIM-foh-site)
A type of immune cell that has moved from the blood into a tumor. Tumor-infiltrating lymphocytes can recognize and kill cancer cells. In cancer therapy, tumor-infiltrating lymphocytes are removed from a patient’s tumor, grown in large numbers in a laboratory, and then given back to the patient to help the immune system kill the cancer cells. Also called TIL.