Abstract: Objective Hepatocellular carcinoma (HCC) is one of the most common liver malignancies in the world. The etiology and molecular events HCC are still unclear. We tried to identify the key pathogenic gene, the cell division cycle 20 (CDC20) by comprehensive bioinformatics, which was related to the pathogenesis of HCC with certain underlying molecular mechanism. Methods We downloaded GSE36376 gene expression profile from Gene Expression Omnibus (GEO) database, found 433 samples, of which 240 HCC tissues and 193 of normal liver tissues, and were analyzed by comprehensive bioinformatics. The R software in RStudio was applied to screen the differential gene expression (DEG) in HCC and normal liver tissues, and the protein-protein interaction (PPI) network of DEG was constructed from the STRING database. The Metascape online tool was applied to carry out enrichment analysis, at the same time, the MCODE was used to identify Hub gene. Results The GSE36376 data was screened to get 706 DEGs, among them, a total of 554 down-regulated genes and 152 up-regulated genes were identified; the significant up-regulated genes were UBE2C, CDC20, COL4A1, NUSAP1, HSP90AB1, and CDKN3 from the PPI network; the Metascape enrichment analysis showed that in the GO biological process, it was mainly concentrated in the small molecule catabolism, the monocarboxylic acid metabolism, the steroid metabolism, the cofactor metabolism, the drug catabolism, the primary alcohol metabolism, and the effects of toxic substances; it also involved the organic anion transport, monosaccharide metabolism, aromatic amino acid family metabolism, detoxification, primary alcohol catabolism, and organic cyclic compound catabolism, etc; as for the KEGG signal pathway, it was mainly focused on carbon metabolism, fatty acid degradation, complement and coagulation cascade, tryptophan metabolism and peroxisomes, etc; the Hub genes were UBE2C, CDC20 and HSP90AB1 from MCODE. Conclusion The CDC20 gene obtained by comprehensive bioinformatics is a key gene for pathogenesis of HCC, which might be important for early diagnosis and therapeutic target.

Key words: Hepatocellular carcinoma, Cell division cycle 20, GEO database, Differential gene expression