Introduction: Histone deacetylase (HDAC) inhibitors play a crucial role in restoring the balance of acetylation and deacetylation of lysine residues of histones and non-histone proteins, which are applied to treat several diseases including cancer. Area covered: This review covers recent efforts in the synthesis and applications of inhibitors and hybrid inhibitors targeting HDAC from 2017-2019. Expert opinion: HDACs are important epigenetic targets and HDAC inhibitors have become important biologically active compounds for the treatment of cancers. Among the recent patents available, most of them place emphasis on HDAC selective inhibitors and multitarget HDAC inhibitors. Although great accomplishments have been achieved in developing HDAC selective inhibitors, there is still an urgent need for discovery of novel HDAC inhibitors with new zinc binding groups avoiding the unfavorable pharmacokinetics profiles of hydroxamic acid. Apart from cancer therapy, HDAC inhibitors have recently been considered as a new strategy in treating other human diseases, such as alcohol use disorder (AUD), neurological disorders, age-related diseases, and so forth.

JAKs, a key family of cytoplasmic tyrosine kinases acting as a requisite part in the signaling process of growth factors and cytokines, important for immunity responses and hematopoiesis have become attractive targets for a considerable number of immune, inflammatory and hematopoietic diseases. Moreover, the JAK signal system has drawn significant attention in recent years as therapeutic targets including JAKs, STATs and JAK/STAT signal pathway. Herein, we present a review of the JAK/STAT signal pathway, the structure, biological function, mechanism of the JAKs and STATs along with a summary of the up-to-date clinical or approved JAK inhibitors which are involved in the treatment of various kinds of tumors and other immunity indications. Moreover, kinds of recently discovered JAKs inhibitors with potent activity or promising selectivity are also briefly discussed.