CYP39A1 and hepatocellular carcinoma: Moreover, CYP39A1 was upregulated through RORα overexpression in HEK293 cells (Figure 3), while RORα knockdown by siRNA significantly downregulated CYP39A1 expression in human hepatoma cells (Figure 4), suggesting that CYP39A1 expression is activated via RORα nuclear receptors.