Fc Fragment of IgE Receptor Ig (FCER1G) acts as a key gene involved in cancer immune infiltration and tumour microenvironment.

Although recent studies have revealed the relationship between Fc Fragment of IgE Receptor Ig (FCER1G) and human tumours, there is still a lack of a more comprehensive pan-cancer analysis of FCER1G as an immune-related gene. In this study, we investigated the expression pattern and prognostic value of FCER1G based on multiple databases. Subsequently, we further explored the role of FCER1G in tumour proliferation and metastasis, as well as its genomic alterations and DNA methylation levels, we next assessed the association between FCER1G and the immune infiltrating cells of the tumour microenvironment in different cancers and verified it by immunohistochemical staining. The correlation between FCER1G and immune checkpoint genes expression and its predictive power in the immune checkpoint blockade treatment cohorts were used to evaluate the importance of FCER1G in immunotherapy. Enrichment analysis of FCER1G-associated partners was also performed. In addition, we substantiated the expression of FCER1G in specific cell types of different tumours using single-cell RNA sequencing data from different databases. Our research results showed that FCER1G is up-regulated in most tumour. Positive associations were found between FCER1G expression and tumour prognosis, proliferation, and metastasis, we also found that FCER1G is closely related to the tumour microenvironment and tumour immunity. Moreover, FCER1G-associated partners were enriched in pathways associated with neutrophils activation. Finally, we confirmed that FCER1G was mainly expressed in monocyte/macrophages of the tumour microenvironment. In conclusion, our findings provided a comprehensive understanding of FCER1G in oncogenesis and tumour immunology among various tumours and demonstrated its potential value in prognosis prediction and tumour immunotherapy.