In an effort to study the invasion mechanism of GBM, Annabi et al. demonstrated that a population of CD133+ (a stem cell marker) cells isolated from the U87MG parental cell line increased migratory response to S1P compared with parental U87MG cells, possibly through a combined pathway of S1P /LPA (sphingosine-1-phosphate/lysophosphatidic acid) cell surface receptors signaling and by membrane-type-1 matrix metalloproteinase [80]. Here, PROM1 is linked to glioblastoma.