In Lulu Fan’s study, it was found that increased expression of cyclooxygenase-2 (COX-2) may be critical for apoptosis resistance to endoplasmic reticulum stress, while paeonol downregulated COX-2 in hepatocellular carcinoma cells and reversed this effect (Fan et al., 2018). This evidence concerns the gene PTGS2 and hepatocellular carcinoma.