Dexamethasone is commonly prescribed to manage symptoms from peritumoral edema in patients with glioblastoma multiforme (GBM). But this new study in the Journal of Neurosurgery suggests it’s not just the patient who’s perking up. GBM stem cells exposed to dex in vitro and in vivo had higher expression of various genes related to tumor invasion, proliferation, and angiogenesis. Genetic changes were particularly prominent in mesenchymal subtype tumors. These findings are pretty thought-provoking, even though they're not coming directly from a clinical setting--keep in mind this would be pretty hard to tease out in patients since worse tumors would probably be the ones having more symptoms. TBL: it’s possible dexamethasone enhances GBM aggressiveness, so add that to the many reasons you should think twice before throwing dex at every headache.