PT  - JOURNAL ARTICLE
AU  - Borst, Linda
AU  - van der Burg, Sjoerd H.
AU  - van Hall, Thorbald
TI  - The NKG2A–HLA-E Axis as a Novel Checkpoint in the Tumor Microenvironment
AID  - 10.1158/1078-0432.CCR-19-2095
DP  - 2020 Nov 01
TA  - Clinical Cancer Research
PG  - 5549--5556
VI  - 26
IP  - 21
4099  - http://clincancerres.aacrjournals.org/content/26/21/5549.short
4100  - http://clincancerres.aacrjournals.org/content/26/21/5549.full
SO  - Clin Cancer Res2020 Nov 01; 26
AB  - The success of checkpoint blockade therapy revolutionized cancer treatment. However, we need to increase the fraction of responding patients and overcome acquired resistance to these therapies. Recently, the inhibitory receptor NKG2A received attention as a new kid on the block of immune checkpoints. This receptor is selectively expressed on cytotoxic lymphocytes, including natural killer cells and CD8 T cells, and NKG2A+ T cells are preferentially residing in tissues, like the tumor microenvironment. Its ligand, histocompatibility leucocyte antigen E (HLA-E), is a conserved nonclassical HLA class I molecule that binds a limited peptide repertoire and its expression is commonly detected in human cancer. NKG2A blockade as a standalone therapy appears poorly effective in mouse tumor models, however, in the presence of activated T cells, for example, induced by PD-1/PD-L1 blockade or cancer vaccines, exerts strongly enhanced efficacy. Clinical trials demonstrated safety of the humanized NKG2A-blocking antibody, monalizumab, and first results of phase II trials demonstrate encouraging durable response rates. Further development of this axis is clearly warranted.