CCNE1 and hepatocellular carcinoma: Known cancer genes such as the telomerase reverse transcriptase (TERT) (61), mixed-lineage leukemia 4 (MLL4) (62), and Cyclin E1 (CCNE1) (63) are preferential integration sites in HCC and about one-third of the genes recurrently targeted by HBV integration are cancer-related genes (64).