DLK1 and glioblastoma: Analysis of DLK1 expression in the Allen Institute for Brain Science Ivy Glioblastoma Atlas Project (Ivy GAP) database [34] revealed increased expression of DLK1 in microdissected areas of infiltrating tumor as compared with in the cellular tumor bulk (Fig. 8f), suggestive of a significant role for DLK1 in the invasive behavior of GBM cells.