PECAM1 and glioblastoma: There is the notion that a proportion of glioblastoma vasculature is neoplastic as glioblastoma stem cells may differentiate into CD31-positive endothelial cells or \documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$\alpha$$\end{document}αsmooth muscle actin (SMA)-positive pericytes (Das and Marsden 2013).