Tumour-infiltrating lymphocytes: from prognosis to treatment selection

Tumour-infiltrating lymphocytes (TILs) are considered crucial in anti-tumour immunity. Accordingly, the presence of TILs contains prognostic and predictive value. In 2011, we performed a systematic review and meta-analysis on the prognostic value of TILs across cancer types. Since then, the advent of immune checkpoint blockade (ICB) has renewed interest in the analysis of TILs. In this review, we first describe how our understanding of the prognostic value of TIL has changed over the last decade. New insights on novel TIL subsets are discussed and give a broader view on the prognostic effect of TILs in cancer. Apart from prognostic value, evidence on the predictive significance of TILs in the immune therapy era are discussed, as well as new techniques, such as machine learning that strive to incorporate these predictive capacities within clinical trials.

Automated summary

Tumour-infiltrating lymphocytes (TILs) are crucial in anti-tumour immunity and have prognostic and predictive value. This review discusses the changing understanding of TILs' prognostic value over the past decade, as well as new insights on novel TIL subsets. It also explores the predictive significance of TILs in the era of immune therapy and the incorporation of these predictive capacities into clinical trials through new techniques like machine learning.