Bioinformatics analysis of glypican-3 as a pan-cancer marker and immunotherapeutic target

The aim of this study was to investigate the possibility of glypican-3 (GPC3) as a pan-cancer marker and immunotherapeutic target by bioinformatics analysis. Firstly, the physicochemical properties and structure of GPC3 protein were analyzed based on the encoded protein sequence. Further, the pan-cancer analysis of GPC3 was performed by the Cancer Genome Atlas (TCGA) data. Among them, 6 types of immune cells, 150 immunomodulatory genes and 60 immune checkpoint genes were included. GPC3 protein was a hydrophilic protein composed of 580 amino acids and had signal peptide at 24-25 sites. Its secondary structure was predicted to be 56.90% helix and 43.10% coil. GPC3 gene was located on the X chromosome and was abnormally expression in 22 cancer types, which affected the prognosis of patients. In most cancer types, GPC3 expression was positively correlated with immune checkpoint genes and immune infiltration. Therefore, GPC3 is likely a marker of cancer immune infiltration and poor prognosis, and may become a new immune checkpoint gene, which provide a new idea for cancer treatment.