RRM2 and cirrhosis of liver: In our study, with the differential analysis of microarray data from the GEO database, 11 cell cycle-related key genes (RRM2, NDC80, ECT2, CCNB1, ASPM, CDK1, PRC1, KIF20A, DTL, TOP2A, and PBK) involved in the process of the transition from liver cirrhosis to carcinoma were identified.