In the current study, the specificity of MC1568 for inhibition of HDACs class IIa in 9L gliomas was demonstrated by the lack of changes in [18F]TFAHA accumulation in 9L tumors after pre-treatment of rats with a SIRT1–specific inhibitor EX-52774 (5 mg/kg, i.v. 30 min before administration of [18F]TFAHA). This evidence concerns the gene SIRT1 and glioma.