CCNA2 and hepatocellular carcinoma: Based on a comprehensive expression analysis and survival analysis, 19 genes (ASPM, CCNA2, CDCA2, FAM83D, KIF2C, KIF20A, MCM2, MCM6, PRC1, TK1, TPX2, TROAP, AURKA, CDC20, CENPF, HJURP, KIF4A, MCM5, MELK, NCAPG, PTTG1, TOP2A, TRIP13 and UBE2T as a key gene that may be associated with HCC progression.