CYP19A1 and malignant glioma: Based on previously reported observations that the enzyme aromatase (CYP19A1) is markedly elevated in HGG surgical samples from patients [7, 9] and that the aromatase inhibitor letrozole is effective against malignant glioma in experimental models [8, 31], efforts are in progress to comprehensively characterize the anti-HGG activity of this agent in various animal models.