Cyclin D1 is a regulator of cyclin-dependant kinases which is involved in cell cycle progression and proliferation and is overexpressed in several types of cancers including breast cancer and HCC.32 We assessed the level of cyclin D1 protein in tumor biopsies from mice from different group (HepG2-UI, HepG2-UV-HCMV, and HepG2-WT-HCMV). The gene discussed is CCND1; the disease is hepatocellular carcinoma.