2.3. Functional Annotation for Differentially Expressed Genes

Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) enrichment analyses were conducted using the Database for Annotation, Visualization, and Integrated Discovery (DAVID). GO was composed of biological processes (BP), cell components (CC), and molecular function (MF). The R package ggplot was used to visualize the results. Functional enrichment analysis on all expression data was performed by Gene Set Enrichment Analysis (GSEA). The R packages clusterProfiler and http://org.Hs.eg.db were used to conduct GSEA. The GSEA cutoff point was set as a p value < 0.05 and |normalized enrichment score (NES)| > 1.