In the present study, SL142 and SL325 showed more significant HADC inhibitory activity (HAT activity) in H441 lung cancer cells (Fig. 1B) and suppressed tumor viability in H441 and A549 lung cancer cells than SAHA (Fig. 1C), indicating that SL142 and SL325 are more effective HDAC inhibitors than SAHA. This evidence concerns the gene HDAC9 and lung carcinoma.