title: Identification of the key genes connected with plasma cells of multiple myeloma using expression profiles.
abstract: OBJECTIVE
  To uncover the potential regulatory mechanisms of the relevant genes that contribute to the prognosis and prevention of multiple myeloma (MM).
  
  
  METHODS
  Microarray data (GSE13591) were downloaded, including five plasma cell samples from normal donors and 133 plasma cell samples from MM patients. Differentially expressed genes (DEGs) were identified by Student's t-test. Functional enrichment analysis was performed for DEGs using the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. Transcription factors and tumor-associated genes were also explored by mapping genes in the TRANSFAC, the tumor suppressor gene (TSGene), and tumor-associated gene (TAG) databases. A protein-protein interaction (PPI) network and PPI subnetworks were constructed by Cytoscape software using the Search Tool for the Retrieval of Interacting Genes (STRING) database.
  
  
  RESULTS
  A total of 63 DEGs (42 downregulated, 21 upregulated) were identified. Functional enrichment analysis showed that HLA-DRB1 and VCAM1 might be involved in the positive regulation of immune system processes, and HLA-DRB1 might be related to the intestinal immune network for IgA production pathway. The genes CEBPD, JUND, and ATF3 were identified as transcription factors. The top ten nodal genes in the PPI network were revealed including HLA-DRB1, VCAM1, and TFRC. In addition, genes in the PPI subnetwork, such as HLA-DRB1 and VCAM1, were enriched in the cell adhesion molecules pathway, whereas CD4 and TFRC were both enriched in the hematopoietic cell pathway.
  
  
  CONCLUSIONS
  Several crucial genes correlated to MM were identified, including CD4, HLA-DRB1, TFRC, and VCAM1, which might exert their roles in MM progression via immune-mediated pathways. There might be certain regulatory correlations between HLA-DRB1, CD4, and TFRC.
authors.affiliation: Spinal Surgery, Jining No 1 People's Hospital, Jining, People's Republic of China.
authors.forename: Kefeng
authors.initials: K
authors.lastname: Zhang
authors.affiliation: Spinal Surgery, Jining No 1 People's Hospital, Jining, People's Republic of China.
authors.forename: Zhongyang
authors.initials: Z
authors.lastname: Xu
authors.affiliation: Department of Orthopedics, The People's Hospital of Laiwu City, Laiwu, Shandong Province, People's Republic of China.
authors.forename: Zhaoyun
authors.initials: Z
authors.lastname: Sun
keywords: PPI network; functional enrichment; multiple myeloma; pathway enrichment; transcription factor analysis