Abstract
BACKGROUND: The E2F family of transcription factor 2 (E2F2) plays an important role in the development and progression of various tumors, but its association with hepatocellular carcinoma (HCC) remains unknown. Our study aimed to investigate the role and clinical significance of E2F2 in HCC. METHODS: HCC raw data were extracted from The Cancer Genome Atlas (TCGA). Wilcoxon signed-rank test, Kruskal-Wallis test and logistic regression were applied to analyze the relationship between the expression of E2F2 and clinicopathologic characteristics. Cox regression and Kaplan-Meier were employed to evaluate the correlation between clinicopathologic features and survival. The biological function of E2F2 was annotated by Gene Set Enrichment Analysis (GSEA). RESULTS: The expression of E2F2 was increased in HCC samples. The expression of elevated E2F2 in HCC samples was prominently correlated with histologic grade (OR = 2.62 for G3-4 vs. G1-2, p = 1.80E-05), clinical stage (OR = 1.74 for III-IV vs. I-II, p = 0.03), T (OR = 1.64 for T3-4 vs.T1-2, p = 0.04), tumor status (OR = 1.88 for with tumor vs. tumor free, p = 3.79E-03), plasma alpha fetoprotein (AFP) value (OR = 3.18 for AFP ≥ 400 vs AFP<20, p = 2.16E-04; OR = 2.50 for 20 ≤ AFP<400 vs AFP<20, p = 2.56E-03). Increased E2F2 had an unfavorable OS (p = 7.468e- 05), PFI (p = 3.183e- 05), DFI (p = 0.001), DSS (p = 4.172e- 05). Elevated E2F2 was independently bound up with OS (p = 0.004, hazard ratio [HR] = 2.4 (95% CI [1.3-4.2])), DFI (P = 0.029, hazard ratio [HR] = 2.0 (95% CI [1.1-3.7])) and PFI (P = 0.005, hazard ratio [HR] = 2.2 (95% CI [1.3-3.9])). GSEA disclosed that cell circle, RNA degradation, pyrimidine metabolism, base excision repair, aminoacyl tRNA biosynthesis, DNA replication, p53 signaling pathway, nucleotide excision repair, ubiquitin-mediated proteolysis, citrate cycle TCA cycle were notably enriched in E2F2 high expression phenotype. CONCLUSIONS: Elevated E2F2 can be a promising independent prognostic biomarker and therapeutic target for HCC. Additionally, cell cycle, pyrimidine metabolism, DNA replication, p53 signaling pathway, ubiquitin-mediated proteolysis, the citrate cycle TCA cycle may be the key pathway by which E2F2 participates in the initial and progression of HCC.