The phosphorylation of Ser181 residue of PAK4 was observed in mitosis [77,78], in human kinome analysis [125], in TCR signaling analysis [152], in human embryonic stem cells differentiation [95], in human cancer cells and human liver phospho-proteomic analysis [80,153], as well as in the analysis of 14-3-3 interactome [144]. Here, PAK4 is linked to cancer.