TMP269 is a selective inhibitor of class IIa histone deacetylases (HDACs), particularly HDAC4, HDAC5, HDAC7, and HDAC9. It is widely used in biomedical research to study the role of these enzymes in gene regulation, cellular differentiation, and disease progression. Due to its ability to modulate epigenetic activity, TMP269 has shown potential in cancer research, where class IIa HDACs are implicated in tumor growth and metastasis. It is also investigated for its effects on immune cell function and inflammation, making it a valuable tool in immunology and autoimmune disease studies. Additionally, TMP269 is used in stem cell and developmental biology to explore how HDAC inhibition influences cell fate and tissue regeneration. Its selectivity makes it a preferred compound for probing specific HDAC functions without broad off-target effects.