Among the epigenetic changes, histone acetylation has been recognized as a fundamental process that strongly affects gene expression regulation. Disrupt of this phenomenon has been linked to carcinogenesis. In this review, we analysed studies reporting the process of histone modification, the enzymes associated and affected genes concerning human malignancies and histone enzyme inhibitor drugs used in cancer treatment. Variable degrees of expression of HDACs (histone deacetylases) and HATs (histone acetyltransferases) are found in many human malignant tissues and the histones acetylation seems to influence different processes including the progression of cell cycle, the dynamics of chromosomes, DNA recombination, DNA repair and apoptosis. Thus, the control of aberrant activity and/or expression of these proteins have been favorable in treatment of diseases as cancer. HDACi have shown efficacy in clinical trials in solid and hematological malignancies. Therefore, the development and use of HDACs inhibitors are increasing, leading to continue studying these enzyme expressions and behavior, aiming to determine tumors that will respond better to this type of treatment.