Metaphase Cytogenetics Adds to Gene Expression Profiling in the Identification of High Risk Multiple Myeloma.

Abstract

The International Staging System (ISS), based on B2-microglobulin and albumin levels at the time of diagnosis, has now generally been adopted as a new prognostic classification system for multiple myeloma (MM). While readily and widely applicable, ISS does not account for genetic disease features, such as metaphase (CA) and interphase fluorescence in situ hybridization (FISH) cytogenetic abnormalities, which when examined in the context of standard prognostic variables, confer higher hazards of relapse and disease-related death. Recently, gene expression profiling (GEP) uncovered the major prognostic significance for outcome of high expression of CKS1B, a gene mapping to an amplicon at chromosome 1q21. We have performed a comprehensive study of CA, FISH, GEP and ISS staging in 351 newly diagnosed MM patients, treated uniformly on Total Therapy 2. We have analyzed outcome based on a combination of high CKS1B by GEP and CA. GEP-based t(11;14) was prognostically favorable, irrespective of expression of CKS1B and, therefore, was removed from the group of patients with high CKS1B expression. After this adjustment, with the combination of both CA and high CKS1B (approximately 10% of all patients) conferred a very poor outcome with only 24% and 40% of such patients being event-free and/surviving at 3 years, compared with 72% and 84% for the others (p values : <.0001). Such patients fared poorly, irrespective of their ISS stage. Similar prognostic information could be gained by combining CA with FISH-defined amplification of 1q21 and t(11;14). Because of their major prognostic impact, all newly diagnosed patients should be tested for these genetic markers. Novel treatment modalities are justified in the small subgroup of such poor prognosis patients, since they derive only a minor benefit from advances in MM therapy. [Display omitted]