Background: Non-invasive approaches to brain tumour detection and diagnosis are limited by the absence of clinically validated circulating biomarkers. This study utilised a miniaturised tissue perfusion model to maintain human brain tumour tissue ex vivo with the aim of identifying tissue-derived proteins with potential biomarker utility. Methods: 55 tumour samples from 11 different brain tumours (glioblastoma n = 4, low-grade glioma n = 4, brain metastases n = 3) were micro-dissected and maintained ex vivo on a continuous-flow perfusion device for 168 h. Proteomic analysis of tumour effluent was performed by reversed-phase capillary liquid chromatography-mass spectrometry. Two candidate proteins—extracellular matrix protein 1 (ECM1) and cathepsin D—were quantified using ELISA. Results: All tumour subtypes retained tissue viability over 168 h of perfusion. Proteomic profiling identified 90 tissue-derived proteins in the tumour effluent. Many proteins corresponded to previously described cancer biomarkers such as glial fibrillary acidic protein (GFAP) while others, including Serpin A12 and collapsin response mediator protein-2 (CRMP2), had not yet been described in a brain tumour context. ELISA confirmed significantly higher ECM1 levels in high-grade glioma effluent compared with low-grade glioma (p = 0.0407), whereas cathepsin D levels did not differ significantly between tumour types. Conclusions: The ex vivo perfusion model effectively preserved primary and metastatic human brain tumour tissue and enabled direct characterisation of tumour-secreted proteins. The proteins identified here warrant further validation as tumour biomarkers in patient serum or cerebrospinal fluid.
Perkins et al. (Wed,) studied this question.