AUTHOR=Ling Bo , Ye Guangbin , Zhao Qiuhua , Jiang Yan , Liang Lingling , Tang Qianli 

TITLE=Identification of an Immunologic Signature of Lung Adenocarcinomas Based on Genome-Wide Immune Expression Profiles

JOURNAL=Frontiers in Molecular Biosciences

VOLUME=7

YEAR=2021

URL=https://www.frontiersin.org/journals/molecular-biosciences/articles/10.3389/fmolb.2020.603701

DOI=10.3389/fmolb.2020.603701

ISSN=2296-889X

ABSTRACT=<p><bold>Background:</bold> Lung cancer is one of the most common types of cancer, and it has a poor prognosis. It is urgent to identify prognostic biomarkers to guide therapy.</p><p><bold>Methods:</bold> The immune gene expression profiles for patients with lung adenocarcinomas (LUADs) were obtained from The Cancer Genome Atlas (TCGA) and the Gene Expression Omnibus (GEO). The relationships between the expression of 45 immune checkpoint genes (ICGs) and prognosis were analyzed. Additionally, the correlations between the expression of 45 biomarkers and immunotherapy biomarkers, including tumor mutation burden (TMB), mismatch repair defects, neoantigens, and others, were identified. Ultimately, prognostic ICGs were combined to determine immune subgroups, and the prognostic differences between these subgroups were identified in LUAD.</p><p><bold>Results:</bold> A total of 11 and nine ICGs closely related to prognosis were obtained from the GEO and TCGA databases, respectively. <italic>CD200R1</italic> expression had a significant negative correlation with TMB and neoantigens. <italic>CD200R1</italic> showed a significant positive correlation with <italic>CD8A, CD68</italic>, and <italic>GZMB</italic>, indicating that it may cause the disordered expression of adaptive immune resistance pathway genes. Multivariable Cox regression was used to construct a signature composed of four prognostic ICGs (<italic>IDO1, CD274, CTLA4</italic>, and <italic>CD200R1</italic>): Risk Score = −0.002<sup>*</sup><italic>IDO1</italic>+0.031<sup>*</sup><italic>CD274</italic>−0.069<sup>*</sup><italic>CTLA4</italic>−0.517<sup>*</sup><italic>CD200R1</italic>. The median Risk Score was used to classify the samples for the high- and low-risk groups. We observed significant differences between groups in the training, testing, and external validation cohorts.</p><p><bold>Conclusion:</bold> Our research provides a method of integrating ICG expression profiles and clinical prognosis information to predict lung cancer prognosis, which will provide a unique reference for gene immunotherapy for LUAD.</p>