Gene expression profiling is a powerful tool that has varied utility. It enables classification of multiple myeloma into subtypes and identifying genes directly involved in disease pathogenesis and clinical manifestation. The present invention used gene expression profiling in large uniformly treated population of patients with myeloma to identify genes associated with poor prognosis. It also demonstrated that over-expression of CKS1B gene, mainly due to gene amplification that was determined by Fluorescent in-situ hybridization to impart a poor prognosis in multiple myeloma. It is further contemplated that therapeutic strategies that directly target CKS1B or related pathways may represent novel, and more specific means of treating high risk myeloma and may prevent its secondary evolution.