Objective: To analyze the expression of glutathione peroxidase 1 (GPX1) in hepatocellular carcinoma (HCC) tissue and its significance by bioinformatics approaches. 
Methods: The expression data of GPX1 in normal lover tissue and HCC tissue were obtained in Ualcan database, the co-expressed genes of GPX1 were retrieved in LinkedOmics, and the biological processes and functions of these genes were determined by GO enrichment analysis and KEGG pathway analysis. Then, the interaction network of the proteins encoded by the relevant genes was analyzed by using STRING. Finally, the relationship between GPX1 expression and the prognosis of the HCC patients was analyzed based on GEPIA database.
Results: Compared with normal liver tissue, the expression levels of GPX1 in HCC tissues from patients with different disease stages (except stage IV) or different ages were significantly increased, further the GPX1 expression levels in HCC tissues from male patients were significantly higher than that from female patients (all P<0.05). The co-expressed genes of GPX1 mainly participated in the biochemical processes such as the transcription and translation of genes, ubiquitination and sulfonylation of proteins, regulation of mRNA stability, and translation of proteasome complex and mitochondria, and were involved in the TGF-β, mTOR, WNT, MAPK, HIF-1α, NF-κB, VEGF and Notch pathways as well as cancer-related pathways. Ten proteins encoded by HCC-related genes were found having interactions with GPX1 encoded protein. The overall survival rates and disease-free survival rates in HCC patients with high GPX1 expression were significantly lower than those in HCC patients with low GPX1 expression (P=0.048, P=0.035).
Conclusion: GPX1 expression is increased in HCC tissue, and its expression is closely related to the occurrence and development as well as prognosis of HCC. So, it can be used as a marker for screening and prognosis estimation of HCC.