High expression of nucleoporin 133 mRNA in bone marrow CD138+ cells is a poor prognostic factor in multiple myeloma

Recent advances in plasma cell biology and molecularly-targeted therapy enable us to employ various types of drugs including immunomodulatory drugs, proteasome inhibitors, and immunotherapy. However, the optimal therapeutic strategies to introduce these drugs for heterogeneous patients with multiple myeloma (MM) have not yet been clarified. In the present study, we attempted to identify a new factor indicating poor prognosis in CD138+ myeloma cells using accumulated Gene Expression Omnibus (GEO) datasets from studies of MM and to assess the relationship between gene expression and survival using MAQC-II Project Myeloma (GSE24080). Five GEO datasets (GSE5900, GSE58133, GSE68871, GSE57317 and GSE16791) which were analyzed by the same microarray platform (GLP570) were combined into one MM database including various types of MM. However, we found that gene expression levels were quite heterogeneous. Hence, we focused on the differentially-expressed genes (DEGs) between newly-diagnosed MM and relapsed/refractory MM and found that the expression levels of more than 20 genes changed two-fold or more. Additionally, pathway analysis indicated that six pathways including Hippo signaling were significantly enriched. Then, we applied all DEGs and genes associated with core enrichment for GSE24080 to evaluate their involvement in disease prognosis. We found that nucleoporin 133 (NUP133) is an independent poor prognostic factor by Cox proportional hazard analysis. These results suggested that high expression of NUP133 could be useful when choosing the appropriate MM therapy and may be a new target of MM therapy.