Within the nucleus, HBV facilitates viral replication and transcription, alongside the dysregulation of cancer-related gene expression, including cyclin A2 (CCNA2), telomerase reverse transcriptase (TERT), myeloid/lymphoid or mixed-lineage leukemia 4 (MLL4), tumor protein P53 (TP53), catenin β1 (CTNNB1), lysine methyltransferase 2B (KMT2B), and cyclin E1 (CCNE1), through the integration of covalently closed circular DNA (cccDNA) into the hepatocyte genome [22] (Table 1). The gene discussed is CCNE1; the disease is cancer.