HDAC9 and cancer: When the resulting hybrid derivatives were tested for potency in various cancer cell lines, they found that two compounds (4 and 5)-compound 4 with an alkyl linker and compound 5 with a pyrimidine linker showed excellent HDAC and PI3K inhibition compared to the reference HDAC inhibitor SAHA and PI3K inhibitor: BKM120, respectively (Figure 8).