PAK4 and colonic neoplasm: Similar to recent results in pancreatic acinar cells [41], PAK4 regulates melanogenesis via the ß-catenin/MITF pathway [96]; PAK4 activates α-MSH/UVB-induced melanogenesis via Wnt/ß-catenin [96]; and the inhibition of PAK4 attenuates nuclear ß-catenin, which reduces the migration, invasion and/or growth in A549 human lung cancer cells [159] and colon cancer cells [189], as well as the growth of normal cells [159].