To date, in HCC, no single tumor mutation is predominant enough to warrant the use of PARP inhibitors alone, although it should be noted that based on in vitro models [17], the expression of the HBV HBx protein in HBV-associated HCC may result in a DNA-repair-deficient background that might allow such an approach (discussed below). The gene discussed is PARP1; the disease is hepatocellular carcinoma.