AKT1 and Proteus syndrome: In conclusion, we have shown that AKT1 E17K-positive cell lines and tissues derived from patients with Proteus syndrome respond in a concentration-dependent manner to ARQ 092 and that ARQ 092 offers the potential to reduce AKT signaling at concentrations predicted to have few clinical adverse effects, thus validating ARQ 092 as a potential novel therapeutic for Proteus syndrome and supporting its clinical development in patients with Proteus syndrome.