Comprehensive Analysis of Expression and Prognostic Value of Selenoprotein Genes in Thyroid Cancer.

Low selenium levels are associated with an increased incidence and advanced stage of thyroid cancers (THCAs). In response to changes in selenium levels, a hierarchy of selenoprotein biosynthesis allows tissue-specific fine-tuning of the 25 selenoproteins. To determine the role of individual selenoproteins on thyroid carcinogenesis, we carried out a multiomic data mining study. The expression levels of individual selenoproteins and their correlations with prognosis in THCAs were analyzed using Oncomine, GEPIA, and Kaplan-Meier plotter platforms. Co-expression analyses using the cBioportal database were carried out to identify genes that are correlated with selenoproteins. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichments were performed for genes correlated with selenoproteins that were identified as clinically significant. and were significantly downregulated in THCAs and were associated with poor prognoses. Biological processes including negative regulation of growth and angiogenesis were enriched in -positively and -negatively correlated genes, respectively. Many biological processes including negative regulation of growth and MAPK cascade were enriched in -positively and -negatively correlated genes, respectively. The antitumor effects of might be attributed to their protection against endoplasmic reticulum (ER) stress. was revealed to be correlated with ER stress, mitochondrial translation, and telomere maintenance. Biological processes of -correlated genes were enriched in redox processes and ER calcium ion homeostasis. Moreover, cell adhesion and angiogenesis were also shown to be negatively regulated by , providing an antimetastatic effect similar as . This study explored the distinct roles of the 25 selenoproteins in THCA pathogenesis, providing potential oncosuppressing effects of 6 selenoproteins.