O26 Intertumoural heterogeneity in the structure of the neurovascular unit in glioma: a retrospective observational cohort study

Abstract Introduction The neurovascular unit (NVU) is implicated in glioma tumourigenesis and treatment resistance but intertumoural heterogeneity not well characterised. We evaluated the structure of NVU across tumour grades, primary recurrent disease. determined association to overall survival. Method Ethics approval was obtained (15/ES/0094). A tissue microarray constructed using biopsies from 137 patients immunostained for endothelial cells (CD31), extracellular matrix (collagen-IV), pericytes (PDGFR-β α-SMA) tight junctions (claudin-V). immunostaining assessed QuPath software compared by one-way analysis variance with Tukey post-hoc testing. Association survival univariate Cox regression hazard ratios (HR). Result Primary grade IV tumours had greater CD31+ than II (P = 0.046) or 0.013). After normalising CD31+, collagen-IV+ PDGFR-β+ III 0.002), < 0.001) 0.001). Normalised α-SMA+ 0.021). CD31 + (HR: 1.028, P 0.004) collagen-IV 1.014, 0.008) were negative prognostic factors. normalisation, PDGFR-β 0.975, 0.004), α-SMA 0.971, 0.020) claudin-V 0.994, 0.021) positive Conclusion Neurovascular remodeling a feature malignancy have altered phenotypes. Markers pericytes, supplement classical grading features predict behavior. Take-home Message