Clinical Value for Diagnosis and Prognosis of Signal Sequence Receptor I (SSR I) and Its Potential Mechanism in Hepatocellular Carcinoma: A Comprehensive Study Based on High-Throughput Data Analysis

Objective: Hepatocellular Carcinoma (HCC) has the characteristics of high incidence and poor prognosis. However, the underlying mechanism of HCC has not yet been fully elucidated. This study aims to investigate the potential mechanism and clinical significance of signal sequence receptor (SSR1) in HCC through bioinformatics methods. Methods: Four online (GEPIA, TIMER, TCGA, and GEO) databases were used to explore the expression level of SSR1 in HCC. The summary receiver operating characteristic (SROC) analysis and standardized mean difference (SMD) calculation were performed further to detect its diagnostic ability and expression level. The Human Protein Atlas (HPA) database was applied to verify the level of SSR1 protein expression. Chi-square test and Fisher's exact test were carried out to determine the clinical relevance of SSR1 expression. KM survival analysis, univariate and multivariate COX regression analyses were employed to explore the prognostic impact of SSR1. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis and Gene set enrichment analysis (GSEA) were implemented to reveal the underlying mechanism of SSR1. Quantitative Real-Time Polymerase Chain Reaction (QRT-PCR) was used to verify the expression of SSR1 in HCC. Results: SSR1 was significantly overexpressed in HCC (SMD=1.25, P=0.03) and had the moderate diagnostic ability (AUC=0.84). SSR1 expression was significantly correlated with T stage, Gender, Pathologic stage (All P<0.05). Patients with high SSR1 expression had shorter overall survival (OS). Univariate and multivariate Cox regression analyses showed that high SSR1 expression was an independent risk factor for poor prognosis. KEGG analysis showed that SSR1-related genes were enriched in the cell cycle, DNA replication, and TGF-beta signaling pathway. GSEA analysis also shows that the high expression of SSR1 is related to the activation of the above three signal pathways. qRT-PCR showed that the SSR1 expression in HCC was significantly higher than the Peri-carcinoma tissue (PHCC) and the corresponding normal liver tissue. Conclusion: SSR1 expression was significantly up-regulated, and it had the potential as a biomarker for the diagnosis and prognosis of HCC. It was very likely to participate in the occurrence and development of HCC by regulating the cell cycle. In summary, our study comprehensively analyzed the clinical value of SSR1 and also conducted a preliminary study on its potential mechanism, which will provide inspiration for the in-depth study of SSR1 in HCC.