HMMR and glioblastoma: These data suggest that CD44 may promote the Warburg effect (aerobic glycolysis) in cancer cells that are CD44+.[67] CD44 and RHAMM, both receptors for hyaluronan, are expressed in GBM in higher levels than low‐grade gliomas or non‐neoplastic specimens of human brain.[68] RHAMM expression is higher at the invasive edges of gliomas, while core regions express more CD44.[69] These hyaluronan receptors are both suppressed by p53,[70, 71] suggesting that early progression through cell cycle checkpoints and capacity of migration are related.[72]