The non-coding RNA (ncRNA)-mediated high expression of polycomb group factor 1 (PCGF1) is a prognostic biomarker and is correlated with tumor immunity infiltration in liver hepatocellular carcinoma

BACKGROUND: Liver hepatocellular carcinoma (LIHC) has a poor prognosis worldwide. Polycomb group factor 1 (PCGF1) was recently reported to play a tumor suppressive role in cancers. However, the molecular mechanism and competitive endogenous ribonucleic acid (ceRNA) regulatory networks of PCGF1 in LIHC are still unclear. METHODS: We constructed a PCGF1 ceRNA regulatory network in LIHC and identified potential prognostic markers, especially for tumor immunity. We identified the gene expression profiles and conducted correlation and survival analyses of PCGF1 and the related RNAs. We also explored the clinicopathological features and diagnostic and prognostic values of PCGF1 and constructed a nomogram to predict 1-, 3-, and 5-year survival. Based on a variety of bioinformatics tools, we confirmed the PCGF1-related signaling pathways in LIHC. Finally, the role of PCGF1 in immune cell infiltration was also analyzed. RESULTS: We found that PCGF1 was overexpressed in LIHC (P<0.001) and was linked to a poor prognosis in terms of overall survival (OS, P=0.029), the progress-free interval (PFI, P=0.002), and disease-free survival (DFS, P=0.02). Hsa-miR-22-3p was highly negatively correlated with PCGF1. Further, 3 upstream long non-coding RNAs (lncRNAs) (i.e., AC016405.3, BX284668.6, and MIR4435-2HG) were confirmed to further research. PCGF1 was positively associated with pathologic tumor stages (P=0.001), histologic grade (P=0.030), alpha fetoprotein (AFP) level (P=0.030), and vascular invasion (P=0.022). The area under the curve of PCGF1 was 0.983 [confidence interval (CI): 0.972–0.994]. In the multivariate analyses, high PCGF1 expression remained an independent factor associated with OS [hazards ratio (HR): 1.696, P=0.027], DSS (HR: 2.139, P=0.024), and the PFI (HR: 1.512, P=0.034). We found that PCGF1 was involved in some malignancy-associated signaling pathways and plays a role in regulating the immune response. CONCLUSIONS: We confirmed the upstream ceRNA regulatory network of PCGF1 in LIHC. PCGF1 has an oncogenic effect and correlates with tumor immunity.