AUTHOR=Wang Guohui , Li Haonan , Pan Jie , Yan Tianfang , Zhou Huandi , Han Xuetao , Su Linlin , Hou Liubing , Xue Xiaoying 

TITLE=Upregulated Expression of Cancer-Derived Immunoglobulin G Is Associated With Progression in Glioma

JOURNAL=Frontiers in Oncology

VOLUME=11

YEAR=2021

URL=https://www.frontiersin.org/journals/oncology/articles/10.3389/fonc.2021.758856

DOI=10.3389/fonc.2021.758856

ISSN=2234-943X

ABSTRACT=<sec><title>Objective</title><p>Gliomas are the most aggressive intracranial tumors accounting for the vast majority of brain tumors with very poor prognosis and overall survival (OS). Cancer-derived immunoglobulin G (cancer-IgG) has been found to be widely expressed in several malignancies such as breast cancer, colorectal cancer, and lung cancer. Cancer-IgG could promote tumorigenesis and progression. However, its role in glioma has not been revealed yet.</p></sec><sec><title>Methods</title><p>We mined open databases including the Chinese Glioma Genome Atlas (CGGA), The Cancer Genome Atlas (TCGA), and the Gene Expression Omnibus (GEO) to study the role of <italic>IGHG1</italic>, which encodes cancer-IgG in glioma. Examination of the differential expression of <italic>IGHG1</italic> was carried out in the GEO and TCGA databases. Furthermore, its expression in different molecular subtypes was analyzed. Stratified analysis was performed with clinical features. Subsequently, immune infiltration analysis was conducted using single-sample gene set enrichment analysis (ssGSEA). GSEA was performed to reveal the mechanisms of <italic>IGHG1</italic>. Lastly, immunohistochemistry was processed to validate our findings.</p></sec><sec><title>Results</title><p>In this study, we found that the expression of <italic>IGHG1</italic> was higher in glioma and molecular subtypes with poor prognosis. The overall survival of patients with a high expression of <italic>IGHG1</italic> was worse in the stratified analysis. Immune infiltration analysis indicated that the expression level of <italic>IGHG1</italic> was positively correlated with the stromal score, ESTIMATE score, and immune score and negatively correlated with tumor purity. Results from the GSEA and DAVID demonstrated that <italic>IGHG1</italic> may function in phagosome, antigen processing and presentation, extracellular matrix structural constituent, antigen binding, and collagen-containing extracellular matrix. Finally, immunohistochemistry assay validated our findings that patients with a high expression of cancer-IgG had poor OS and disease-free survival (DFS).</p></sec><sec><title>Conclusion</title><p>Cancer-IgG is a promising biomarker of diagnosis and treatment for patients with glioma.</p></sec>