The results of GSEA analysis indicated that LGG samples in the high expression group of FCGR3A gene were mainly enriched in allograft rejection, autoimmune thyroid disease, graft-versus-host disease, JAK−STAT signaling pathway, viral myocarditis, and the response of stress signaling pathway, indicating that FCGR3A may be involved in multiple biological processes in the occurrence and development of LGG. Here, FCGR3A is linked to viral myocarditis.