STEAP4 and Hepatic steatosis: We previously demonstrated that hepatic STAMP2 plays a pivotal role in preventing HFD-induced NAFLD and that both cilostazol and recombinant fibroblast growth factor 21 (FGF21) ameliorate HFD-induced hepatic steatosis by enhancing hepatic STAMP2 expression through AMPK [25,26,27].