The current study investigated the effect of trichostatin A (TSA) on mitochondrial/intrinsic [pro- (Bax, Bak, and Bim) and anti- (Bcl-2, Bcl-xL, and Mcl-1) apoptotic genes] and cytoplasmic/extrinsic (DR4, DR5, FAS, FAS-L, and TRAIL genes) pathways, histone deacetylase 1, 2, and 3, p53, p73, cell viability, and apoptosis in hepatocellular carcinoma (HCC) HCCLM3, MHCC97H, and MHCC97L cell lines. The gene discussed is TP53; the disease is hepatocellular carcinoma.