PCNA and hepatocellular carcinoma: Moreover, the results of western blot showed that the protein expression levels of NUB1 were lower in six tested HCC cells (i.e., HCCLM3, Hep3B, HepG2, SMMC7721, Huh7, and MHCC97H) than in normal hepatocytes (HL-7702), whereas the opposite was true for PCNA, and correlation analysis also showed a negative correlation between them (Fig. 1F, G).