As a previous report indicated that RNAi-mediated downregulation of ATF5 in hepatocellular carcinoma cells caused a reduced expression of GDF-15 (33), we next validated both ATF4 and ATF5 as regulators of GDF-15 in EHE cells through their siRNA-mediated knockdown. The gene discussed is ATF5; the disease is hepatocellular carcinoma.