Some flavonols, such as fisetin (3,3′,4′,7-tetrahydroxyflavone), act by phosphorylating extracellular signal-regulated kinases (ERK1/2), also promoting the inhibition of a disintegrin and the metalloproteinase 9 (ADAM9) [5,115], a protein associated with the GBM invasion and the degree of malignance, acting as a factor of prognosis in gliomas [116]. The gene discussed is MAPK3; the disease is glioblastoma.