For example, mdm2 is the master regulator of tumor suppressor protein p53 (Momand, Wu & Dasgupta, 2000), while the p53 gene is a master regulator of diverse cellular processes and a potential therapeutic target for cancer (Farnebo, Bykov & Wiman, 2010); and snai1 is the master regulator of epithelial-mesenchymal transition, but it is regulated by Pak1 through phosphorylation (Takahashi et al., 2013), which implicates Pak1 as a master regulator of epithelial-mesenchymal transition (Yang et al., 2005). This evidence concerns the gene PAK1 and cancer.