Tumour infiltrating lymphocytes

October 17, 2023

Tumour infiltrating lymphocytes (TILs) are immune cells (typically T cells) that gather around or inside a tumour. TILs are important because they can kill cancer cells and prevent the disease from spreading to other parts of the body. Immune checkpoint inhibitors (such as PD-L1 inhibitors) work by preventing cancer cells from blocking the natural activity of TILs.

How do pathologists measure tumour infiltrating lymphocytes?

When examining a tumour for TILs, pathologists typically use two categories to describe the response:

  • Brisk – This means that lots of lymphocytes were seen in and around the tumour.
  • Non-brisk – This means that very few lymphocytes were seen around the tumour.

Tumours with non-brisk TILs are more likely to spread to a lymph node or a distant part of the body such as the lungs.

About this article:

This article was written by doctors to help you read and understand your pathology report. Contact us if you have questions about this article or your pathology report.

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