KLRG1 and neoplasm: Investigating the expression of KLRG1 on tumour infiltrating ILC populations showed that a higher percentage of ILC in blood (p values ILC1: 0.0001, ILC2: 0.005, ILC3: 0.0002, NK: 0.0001) and breast tissue (p values ILC1: 0.0006, ILC2: 0.02, ILC3: 0.002, NK: 0.03) of patients with malignant breast tumour express KLRG1 compared to patients with benign tumours, consistent with a more activated phenotype (Fig. 3b, and Additional file 1: Figure S2 and Additional file 1: Figure S3).