CXCR4 and glioblastoma: Prognostic indicators for GBM progression, include CD133+/Ki-67+ cells, and the expression of HOX or Nestin genes.29, 30, 31 CD184 (CXCR4 chemokine-receptor) is another surface marker that is significantly correlated with CD133+ cells and has been shown to increase the expression of hypoxia-inducible factor 1 (HIF-1).32