EIF4EBP1 and dermatofibrosarcoma protuberans: Correspondingly, increased expression of the phosphorylated Akt-mTOR pathway proteins including Akt, mTOR, 4EBP1, and S6RP and phosphor-PDGFRα/β have been demonstrated in about half of DFSP tissues by immunoperoxidase studies [21], suggesting that Akt-mTOR pathways are involved in the tumorigenesis of DFSP.