SIRT1 and central nervous system cancer: Furthermore, the results of Logan graphical analyses demonstrated that the decrease in transient retention and distribution volume (DV) of [18F]TFAHA-derived radioactivity in 9L gliomas after administration of MC1568 results mainly from an acute inhibition of HDACs class IIa activity, whereas no changes in the DV of [18F]TFAHA-derived radioactivity were observed in the same 9L tumors after pre-treatment with SIRT1-specific inhibitor EX-527, as compared to baseline.