ELISA confirmed significantly higher ECM1 levels in high-grade glioma effluent compared with low-grade glioma (<i>p</i> = 0.0407), whereas cathepsin D levels did not differ significantly between tumour types.<h4>Conclusions</h4>The ex vivo perfusion model effectively preserved primary and metastatic human brain tumour tissue and enabled direct characterisation of tumour-secreted proteins. Here, CTSD is linked to brain neoplasm.