PAK4 and colorectal cancer: Collectively, these data suggest that RSK2 or PAK4 phosphorylation mediates resistance to 5‐FU chemotherapy and that suppression of RSK2 or PAK4 activation in combination with 5‐FU displays a synergistic inhibitory effect on cell growth and apoptosis in colorectal cancer cells, involving ERK and P53 signaling pathways (Figure S13C, Supporting Information).