Abstract: p21 activated kinase 4 (PAK4) is a member of a family of serine/threonine kinase. PAK4 plays an important role in a variety of cellular functions including cell cycle, cell proliferation, apoptosis, and cytoskeletal reorganization. Recently, PAK4 has been shown to overexpress in a variety of malignancies, and contribute to cancer cell migration and invasion through multiple signalling pathways.