Thus, the following genes had elevated levels in KO HCC tumors compared to WT livers: platelet derived growth factor alpha (Pdgfa, 5-fold), cyclin D1 (Ccnd1, 3-fold), cyclin B2 (Ccnd2, 5-fold), fibroblast growth factor 21 (Fgf21, 9-fold) and E2F transcription factor 7 (E2f7, - 4-fold). Here, CCND2 is linked to hepatocellular carcinoma.