Immune checkpoint blockade is ineffective in some tumours, in part owing to the presence of immunosuppressive myeloid cells in the microenvironment. Here, Molgora et al. report that deficiency of the myeloid receptor TREM2 or treatment with an anti-TREM2 mAb reduces tumour growth in mouse cancer models and enhances the efficacy of anti-PD1 immunotherapy, while triggering changes in the tumour-infiltrating macrophage populations. TREM2 was expressed in infiltrating macrophages in more than 200 human tumours, and expression correlated with worse survival in colorectal and breast cancer.
Nature Reviews Drug Discovery 19, 672 (2020)