TK1 and liver cancer: We found that DEN-induced HCC in our rat model over-expressed 21 genes out of the top 25 genes over-expressed in human HCC, including genes whose high expression is associated with unfavorable prognosis in liver cancer, such as Spp1, Ube2c, Pttg1, Ube2t, Ccnb1, Nt5dc2, G6pd, Cenpw, Tk1, Tacc3 and Stmn1 (Figure 3c, Table S3).