JCAD knockdown by siRNA in Huh‐7 and Huh‐7‐trans cells, the latter is a high‐metastatic hepatoma cells derived from Huh‐7 cells, resulted in down‐regulation of cyclin D1 at both mRNA and protein levels (Figure 6A,B). The gene discussed is CCND1; the disease is hepatocellular carcinoma.