Tumour-infiltrating lymphocyte

Tumour-infiltrating lymphocytes (TILs) are a type of white blood cell that have left the bloodstream and migrated into a tumor. These cells are part of the immune system's response to cancer. TILs can be found in many types of cancer and their presence is often associated with a better prognosis for the patient. The study and utilization of TILs in cancer therapy, particularly in immunotherapy, is an area of active research.

Overview

Tumour-infiltrating lymphocytes are primarily composed of T cells and, to a lesser extent, B cells, natural killer cells, and other types of immune cells. The presence and composition of TILs within a tumor can vary greatly depending on the type of cancer and its location. TILs recognize and attack cancer cells, and their effectiveness can be influenced by various factors, including the ability of cancer cells to evade immune detection and the presence of other immune-suppressive cells in the tumor microenvironment.

Role in Cancer

The role of TILs in cancer is complex and multifaceted. On one hand, a high density of TILs is generally associated with a more effective immune response against the tumor and, consequently, a better clinical outcome for the patient. On the other hand, the tumor microenvironment can suppress the activity of TILs, reducing their ability to fight cancer.

Prognostic Significance

The presence of TILs in tumor tissue has been found to be a significant prognostic factor in various types of cancer, including melanoma, breast cancer, and colorectal cancer. In general, tumors with a higher density of TILs are associated with a better prognosis and increased survival rates.

Therapeutic Implications

The therapeutic potential of TILs has led to the development of treatments that aim to enhance their cancer-fighting capabilities. One such approach is the extraction, expansion, and reinfusion of TILs, a process known as adoptive cell transfer (ACT). This treatment involves collecting TILs from a patient's tumor, growing them in large numbers in the laboratory, and then infusing them back into the patient to help boost the immune system's ability to fight cancer.

Challenges and Future Directions

Despite the promising role of TILs in cancer therapy, there are several challenges to their widespread use. These include the technical difficulties and high costs associated with isolating and expanding TILs, as well as the need for personalized treatment approaches. Furthermore, research is ongoing to better understand the mechanisms by which tumors suppress TIL activity and to develop strategies to overcome these barriers.

See Also

• Immunotherapy
• Cancer immunology
• Adoptive cell transfer
• Checkpoint inhibitor