The chemokine CXCL12 and its receptor CXCR4 promote glioma stem cell-mediated VEGF production and tumour angiogenesis via PI3K/AKT signalling - Ping, Y F; Yao, X H; Jiang, J Y; Zhao, L T; Yu, S C; Jiang, T; Lin, M C; Chen, J H; Wang, B; Zhang, R; Cui, Y H; Qian, C; Wang, J; Bian, X W (J Pathol, 2011)