NAT1 and hepatocellular carcinoma: Among these sixteen genes, ten genes were down-regulated including four well- annotated genes, MSRA, WHSC1L1, ARHGEF10 and NAT1. Although HTPAP gene was significantly down-regulated in HCC cell line with high metastatic potentials (data not shown), and was also down-regulated in the metastatic HCCs, the difference did not reach the statistical criteria in this study.