Revelation of critical genes and pathways involved in hepatocellular carcinoma (HCC) and phylogenetic tree construction of CDK1 protein family An integrated multi-omics bioinformatics analysis

<h2>Background</h2> <p>Hepatocellular carcinoma (HCC) is one of the leading and fastest increasing causes of death in the world. It primarily happens in the people who have been exposed to high-risk factors for a long time, such as the hepatitis B virus, hepatitis C virus, etc. Some similar analysis on HCC were published years ago, and results need updating.</p><h2>Methods</h2> <p>In this study. We analyzed the gene expression pattern obtained from the GEO database in healthy tissue and tumor tissue and identified differentially expressed genes (DEGs), then GO and KEGG pathway analyses were performed subsequently on DEGs. We also used the protein-protein interaction (PPI) network drawn from STRING to find hub genes and analyzed their effects on prognosis and expression level in different stages of HCC from GEPIA. Furthermore, we analyzed the CDK1 in different species and established the phylogenetic tree of the CDK1 family by the MEGA-X (version 5) according to the amino acid sequence of CDK1 in different species.</p><h2>Results</h2> <p>Among all DEGs identified in this study, the CDK1 is the most statically significant hub gene in the perspective of prognosis and differential ex pression. The expression level of CDK1 varies in different stages of HCC. The expression level reaches the highest in stage two and three and reaches the lowest in Stage four. And the human CDK1 gene and ape-like CDK1 gene subtype 5 may be homologous genes. However, human CDK1 gene and the gene encoding human CDK1 protein A chain may be heterozygous genes.</p><h2>Conclusion</h2> <p>CDK1 is a gene with great significance in the diagnosis and prognosis of HCC, more studies that investigate deeply about the CDK1 is needed in the future.</p>