Gene expression profiling defines a high-risk entity of multiple myeloma

Multiple myeloma (MM) is the second most common hematological malignancy and remains incurable. The marked variation in survival of patients with symptomatic myeloma ranging from few months to more than 15 years can be explained by differences in tumor mass, proliferative activity and, more recently, by cytogenetic and molecular genetic characteristics of the myeloma clone. Oligonucleotide microarray-based gene expression analysis was applied to CD138-enriched plasma cells from newly diagnosed patients with symptomatic or progressive multiple myeloma treated with melphalan-based high-dose therapy. Here we discuss recent progress made in the development of molecular-based diagnostics and prognostics for MM from Myeloma Institute for Research and Therapy of University Arkansas for Medical Sciences, where we treat more patients with myeloma than anywhere else in the world. Seven distinct entities of myeloma were elucidated by genomic profiling. Expression extremes of 70 genes from a high-risk signature profile, 30% of which were derived from chromosome 1, were strongly linked to disease-related survival. CKS1B located on chromosome 1q21, responsible for promoting cell cycle progression by inducing the degradation of p27Kip1, represented a strong candidate gene related to rapid patient death and was studied in detail. The data suggest that CKS1B influences myeloma cell growth and survival through SKP2- and P27 (Kip1)-dependent and independent mechanisms and that therapeutic strategies aimed at abolishing CKS1B function may hold promise for the treatment of high-risk disease for which effective therapies are currently lacking.