Glioblastoma following treatment with fingolimod for relapsing-remitting multiple sclerosis.

Glioblastoma is an uncommon and aggressive primary brain tumor with incidence of 3 per 100,000 annually. We report a 50-year-old woman diagnosed with glioblastoma within threeyears of induction of fingolimod therapy for relapsing-remitting multiple sclerosis. Fingolimod, an immunomodulating agent used in the treatment of relapsing-remitting multiple sclerosis, has also been suggested to impart a cardioprotective role in heart failure and arrhythmia via activation of P21-activated kinase-1 (Pak1). In the brain, Pak1 activation has been shown to correlate with decreased survival time amongst patients with glioblastoma. A molecular mechanism underlying a link between fingolimod use and glioblastoma development may involve activation of Pak1. To our knowledge, this is the first report of a potential association between fingolimod use and glioblastoma development.