MAPK9 and cancer: It has been reported that perifosine enhances the antitumor activity of cetuximab in PTEN-deficient cancer cells and that the combination treatment enhanced the inhibition of phosphorylation of AKT, p44/42MAPK and p38MAPK, but offset the phosphorylation of SAPK/JNK that was activated by perifosine treatment alone [29].