For S100B, preclinical studies suggest that its elevation is linked to blood-brain barrier disruption and astrocytic activation caused by metastatic tumors,52 supporting its role as a biomarker for BM.52,53 While these findings supported the potential diagnostic performance of S100B, they also highlighted the need for further validation to harmonize animal and human data. The gene discussed is S100B; the disease is metastatic neoplasm.