Using the publicly available databases GSE14520 (which includes gene expression profiles from 239 normal liver and 249 HCC tissues), GSE121248 (which includes gene expression profiles from 37 normal liver and 70 HCC tissues) and GSE76427 (which includes gene expression profiles from 52 normal liver and 115 HCC tissues), we found that ADRA2A mRNA expression was downregulated in HCC tissue compared normal controls (Fig. 2f–h). This evidence concerns the gene ADRA2A and hepatocellular carcinoma.