B7-H3 expression in an independent brain metastasis cohort. (a) The mixed brain metastasis cohort was comprised of samples from 137 BrMs derived from different primary tumours. (b) The proportion of BrM cases with positive and negative B7-H3 expression across the cohort; ‘others’ consists of ovary, ACC, and NET due to low numbers. (c) B7-H3 subcellular localisation across BrM cases. (d–i) Representative B7-H3 immunohistochemistry images from the mixed brain metastasis cohort: prostate (d), breast (e), melanoma (f), lung (g), renal (h), and colorectal cancer (i). ACC, adenoid cystic carcinoma; BrM, brain metastasis; NET, neuroendocrine tumour. Scale bar: 60 µm.