B7-H3 expression reflects magnetic resonance imaging (MRI)-derived tumour burden and peritumoral brain oedema in adult gliomas: a radiopathological correlation study.

AIM: To determine whether immunohistochemical B7-H3 expression is associated with magnetic resonance imaging (MRI)-derived tumour volume, peritumoral brain oedema volume, and oedema index in adult gliomas. METHODS: This retrospective radiopathological correlation study included 99 consecutive patients with histopathologically confirmed intracranial gliomas surgically treated between 2013 and 2021. B7-H3 expression (clone RBT-B7H3, Bio SB, USA) was evaluated using staining intensity, percentage of positive tumour cells, and a composite immunoreactive score (IRS). Tumour volume (TV), peritumoral brain oedema volume (PTBE), and oedema index (EI) were calculated from orthogonal MRI measurements. Spearman correlation and crude and adjusted linear regression were used. Adjusted models included age, sex, tumour grade, and Ki-67. RESULTS: Median TV was 29.31 cm3 (IQR 12.17-49.12), median PTBE was 84.51 cm3 (IQR 47.59-178.18), and median EI was 4.56 (IQR 3.83-5.00). B7-H3 IRS correlated strongly with TV (r = 0.921, p < 0.001) and PTBE (r = 0.920, p < 0.001), but not with EI (r = -0.105, p = 0.299). After adjustment, B7-H3 IRS remained associated with ln(TV) (beta = 0.228, 95% CI 0.190-0.265, p < 0.001) and ln(PTBE) (beta = 0.178, 95% CI 0.152-0.204, p < 0.001), but not with EI (beta = 0.001, 95% CI -0.083 to 0.084, p = 0.990). CONCLUSION: B7-H3 expression is independently associated with MRI-derived tumour volume and peritumoral brain oedema volume in adult gliomas, but not with oedema index, supporting its relationship with absolute MRI-visible lesion burden.