Identification of key genes and construction of microRNA-mRNA regulatory networks in multiple myeloma by integrated multiple GEO datasets using bioinformatics analysis.

Multiple myeloma (MM) is a common hematological malignancy. To identify key genes and microRNAs in MM, we downloaded two gene expression profiles (GSE16558 and GSE47552) and two microRNA expression profiles (GSE17498 and GSE16558) from the Gene Expression Omnibus (GEO) database. A total of 596 differentially expressed genes (DEGs) and 39 differentially expressed microRNAs (DEMs) were screened out. Pathway analysis showed that upregulated genes were mainly enriched in the "B cell receptor signaling pathway", "Cell cycle" and "NF-kappa B signaling pathway", whereas downregulated genes were mainly enriched in the "Ribosome", "FoxO signaling pathway" and "p53 signaling pathway". We subsequently constructed a protein-protein interaction network of DEGs consisting of 277 genes and 563 interactions. In addition, 32 genes with high degrees in the network were identified as hub genes in MM, e.g. HDAC2, RBBP4, CREB1, and RB1. Additionally, we constructed a microRNA-mRNA regulatory network depicting interactions between DEMs and their targets, including the miR-135b-GADD45A and miR-148a-USPL1 pairs. In conclusion, the results of this data mining and integration help reveal the molecular basis of MM pathogenesis as well as potential biomarkers and therapeutic targets for MM diagnosis and treatment.