PLK4 and hepatocellular carcinoma: To investigate the biological role of PLK4 in HCC, we first investigated the expression of PLK4 in six HCC cell lines (Huh7, BEL‐7402, G2.215, MHCC‐97L, MHCC‐97H, and HepG2) and one immortalized human normal liver cell line L‐02, and found that PLK4 was highly expressed in HCC cell lines, especially Huh7, compared to human normal liver cell line both in mRNA and protein levels (Figures 2A and 4A).