Expression Of TOMM40L Gene In Hepatocellular Carcinoma And Its Effect On Prognosis

Objective:To screen differentially expressed genes in hepatocellular carcinoma（HCC）by transcriptomics and proteomics sequencing technology and bioinformatics analysis,verify their expression levels in HCC tissues,and explore effects on prognosis of HCC patients as biomarkers combining clinicopathological parameters.Methods and Materials:Tissue samples（tumor and adjacent tissues）of 33 and 20 HCC patients from the Department of Hepatobiliary Surgery of the First Affiliated Hospital of Anhui Medical University were harvested for transcriptomics and proteomics sequencing,respectively.According to conditions（P<0.001,|Log₂Fold Change|>2）,transcriptomics data and proteomics data were cross-analysis to screen out common differentially expressed genes and proteins,and the obtained differentially expressed genes and proteins were performed functional enrichment analysis.In addition,47 pairs of paraffin-embedded tissues were collected from the Department of Pathology,The First Affiliated Hospital of Anhui Medical University for histopathological slices,and immunohistochemistry were used to verify the expression of TOMM40L in HCC tissues and adjacent tissues.SPSS23.0 software was used for data analysis.We used chi-square test or Fisher’s exact probability method to analyze the relationship between TOMM40L gene expression level and age,hepatitis B virus（HBV）,gender,and tumor diameter,preoperative serum alpha-fetoprotein（AFP）level,metastasis,tumor differentiation,vascular invasion,liver cirrhosis and other clinicopathological characteristics.Kaplan-Meier survival curve was tested by Log-Rank method to analyze the overall survival（OS）of patients between two groups.Cox regression analysis were used to explore factors affecting OS in patients with HCC.GSEA enrichment analysis was used to explore the main biological processes involved in the TOMM40L gene.A two-sided test with a significance level of P-value less than 0.05 was considered statistically significant.Results:In the first part of this study,according to transcriptome sequencing results,318differentially expressed genes were obtained from tumor tissues and adjacent tissues,including 197 up-regulated genes and 121 down-regulated genes.A total of 76differentially expressed proteins were obtained after intersection analysis of transcriptome and proteomics data,including 44 up-regulated proteins and 32 down-regulated proteins.GO functional annotation showed that these differential genes mainly played important roles in DNA replication,oxidation-reduction process,and protein binding and KEGG functional enrichment analysis showed that differential genes were mainly enriched in metabolic pathways,antibiotic biosynthesis,cell cycle and other pathways.In the second part of the study,the expression of TOMM40L in HCC tissues was significantly higher than that in adjacent tissues by immunohistochemistry.Then,47 HCC patients were performed retrospective analysis,and chi-square test results showed that TOMM40L expression level was significantly correlated with portal vein invasion（P=0.032）and tumor differentiation（P=0.017）.Survival analysis showed that the OS of patients with high TOMM40L expression was significantly shorter than that of patients with low TOMM40L expression（P=0.022）,and multivariate Cox regression analysis suggested that TOMM40L gene might be an independent risk factor for prognosis of HCC patients（HR=11.421,P=0.002）.Finally,we performed GSEA analysis of the TOMM40L gene and found that TOMM40L gene is mainly enriched in biological processes including aminoacyl t RNA biosynthesis,bladder cancer,DNA replication,N-glycan biosynthesis,protein export,and nucleotide metabolism.Conclusion:TOMM40L gene may be an important biomarker of HCC,which is closely related to the prognosis of patients with HCC,and the prognosis of patients with high TOMM40L expression is poor.