AUTHOR=Liu Shixuan , Liu Yanbin , Zhang Xi , Song Xuanlin , Zhang Boxiang , Zhang Yong 

TITLE=Pan-cancer analysis of the prognostic and immunological roles of DEAD-box helicase 5 (DDX5) in human tumors

JOURNAL=Frontiers in Genetics

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/genetics/articles/10.3389/fgene.2022.1039440

DOI=10.3389/fgene.2022.1039440

ISSN=1664-8021

ABSTRACT=<p><bold>Background:</bold> Recent studies have demonstrated the significance of the <italic>DEAD-box helicase 5</italic> (<italic>DDX5</italic>) gene, which is involved in pathways concerning the modification of RNA structures. <italic>DDX5</italic> functions as a coregulator of cellular transcription and splicing, and participates in the processing of small noncoding RNAs. The aberrant regulation of <italic>DDX5</italic> expression possibly plays a significant role in the genesis of cancer. However, there are no comprehensive pan-cancer studies on <italic>DDX5</italic>. This study is the first to conduct a pan-cancer analysis of <italic>DDX5</italic> for aiding the diagnosis and treatment of cancer.</p><p><bold>Methods:</bold> The gene expression, genetic alterations, protein phosphorylation, promoter methylation, immune infiltration, and enrichment analyses of <italic>DDX5</italic> were performed using data retrieved from The Cancer Genome Atlas (TCGA), Genotype-tissue Expression (GTEx), Human Protein Atlas (HPA), Tumor Immunological Estimation Resource 2.0 (TIMER2.0), Gene Expression Profiling Interactive Analysis (GEPIA), DNA methylation interactive visualization database (DNMIVD), and Search Tool for the Retrieval of Interaction Genes/Proteins (STRING). Data analyses were performed with the R software and other webtools.</p><p><bold>Results:</bold> The expression of DDX5 mRNA decreased significantly in 17 cancer types, but increased significantly in eight cancer types. The enhanced expression of DDX5 mRNA in the tumor samples was related to decreased overall survival (OS), progression-free interval (PFI), and disease-specific survival (DSS) in three cancers, but increased OS, PFI, and DSS in other cancers. The DNA promoter methylation level was significantly reduced in eight cancer types, and there were exceptions in the methylation levels of the <italic>DDX5</italic> promoter in four cancer types. The expression of DDX5 mRNA was highly correlated with the infiltration of CD8<sup>+</sup> T cells, cancer-associated fibroblasts, and B cells in a wide variety of malignancies. The findings revealed a strong association between <italic>DDX5</italic> and its co-expressed genes in numerous cancer types. Enrichment analysis suggested that <italic>DDX5</italic> was associated with multiple cellular pathways, including RNA splicing, Notch signaling pathway, and viral carcinogenesis, which was consistent with the results of previous studies.</p><p><bold>Conclusion:</bold> The findings obtained herein provide further information on the oncogenic potential of <italic>DDX5</italic> in diverse tumor types. We propose that <italic>DDX5</italic> has important roles in tumor immunity and the diagnosis of cancer.</p>