Overexpression of PARPBP Correlates with Tumor Progression and Poor Prognosis in Hepatocellular Carcinoma

Abstract

Background: PARP1-binding protein (PARPBP/PARI/C12orf48), a negative regulator of homologous recombination (HR), has been suggested to function as an oncogene in cervical, lung, and pancreatic cancer.

Objective: To investigate the expression profile of PARPBP and its role in hepatocellular carcinoma (HCC).

Methods: Using data from the Cancer Genome Atlas and Human Protein Atlas databases, PARPBP expression level and its clinical implication in HCC were identified by t test and Chi-square test. The prognostic value of PARPBP in HCC was evaluated by Kaplan-Meier method, Cox regression analysis, and nomogram. Gene set enrichment analysis (GSEA) was used to screen biological pathways correlated with PARPBP expression in HCC.

Results: PARPBP was significantly upregulated in HCC tissues compared with normal liver tissues (P < 0.05). High PARPBP expression was significantly associated with elevated serum AFP level, vascular invasion, poor tumor differentiation, and advanced TNM stage (all P < 0.05). Kaplan-Meier analyses suggested that upregulation of PARPBP was correlated with worse overall survival (OS) and recurrence-free survival (RFS) in HCC. Multivariate analyses further confirmed that PARPBP upregulation was an independent indicator of poor OS and RFS (all P < 0.05). The prognostic nomograms based on PARPBP mRNA expression and TNM stage were superior to those based on the TNM staging system alone (all P < 0.05). Besides, PARPBP DNA copy gain and miR-139-5p downregulation were associated with PARPBP upregulation in HCC. GSEA revealed that "cell cycle," "HR," "DNA replication," and "p53 signaling" pathways were enriched in high PARPBP expression group.

Conclusion: PARPBP may be a promising prognostic biomarker and candidate therapeutic target in HCC.

Keywords: Hepatocellular carcinoma; PARI; PARPBP; Prognosis.