To more strictly assess the effect of CCN1 on macrophage migration and tumor growth, we conducted conditional small hairpin RNA (shRNA)-mediated knockdown of CCN1 using lentiviral vectors in DGCs from patient-derived GBM cells (MGG4 and MGG8 DGCs) and U87ΔEGFR cells (Additional file 1: Fig. S6d). This evidence concerns the gene CCN1 and glioblastoma.