After intersecting with DE-miRNAs, a sum of 18 miRNAs were obtained in Venn diagram (Figure 7C), among them, the hsa-mir-326 and hsa-mir-665 were down regulated miRNAs in HCC group (MCM10, CEP55, KIF18A, ORC6, KIF23, CDT1, and PLK4 were up regulated mRNAs in HCC group) (Supplementary Table S13), thus hsa-mir-326 and hsa-mir-665 were regarded as key miRNAs. Here, PLK4 is linked to hepatocellular carcinoma.