STK25 and fatty liver disease: In the first cohort of Stk25-/- mice and wild-type littermates, HCC was triggered by a single injection of diethylnitrosamine (DEN), which is known to alkylate DNA and promote oxidative stress via the production of reactive oxygen species (ROS),20,21 combined with long-term high-fat diet–feeding to induce hepatic steatosis, inflammation, and fibrosis (ie, the spectrum of lesions present in NASH patients).