PLK4 and hepatocellular carcinoma: We first investigated the expression of PLK4 in six HCC cell lines (Huh7, BEL‐7402, G2.215, MHCC‐97L, MHCC‐97H, and HepG2), and found that PLK4 was highly expressed in Huh7 and BEL‐7402 (Figure 4A).