To validate the mRNA expression levels of the screened hub genes between HCC and normal hepatic tissues, a meta-analysis on the mRNA expression levels of BUB1B, CCNB1, CCNB2, CDC20, CDK1, MAD2L1 and RRM2 was performed based on the ONCOMINE database. The gene discussed is RRM2; the disease is hepatocellular carcinoma.