From the Mayo Clinic College of Medicine, Scottsdale, Arizona
Author's disclosure of potential conflicts of interest is found at the end of this article.
Address reprint requests to A. Keith Stewart, MD, 13400 East Shea Boulevard, Scottsdale, AZ 85259; e-mail: stewart.keith{at}mayo.edu
Overview: Clinical outcomes for multiple myeloma are variable and, as in other hematologic malignancies, appear to be driven by disease-initiating genetic events. Indeed, multiple myeloma can usually be classified into genetic high-risk and standard-risk categories using molecular fluorescense in situ hybridization (FISH) and cytogenetic diagnostic testing on diagnostic bone marrow aided by measurement of beta-2-microglobulin, lactate dehydrogenase (LDH), and albumin. Such classifications have important therapeutic implications. Genetically high-risk disease is defined as any of the following: t(4;14), t(14;16), t(14;20), deletion 17p by FISH, or deletion chromosome 13 or hypodiploidy by conventional metaphase cytogenetics. A high serum LDH (> 2 times the upper limit) or beta-2-microglobulin (> 5.5 mg/L) also can be considered a high-risk feature, This classification will identify 25% of patients with multiple myeloma who are at high genetic risk for early progression after conventional therapies. Because patients at high risk often experience early relapse after conventional therapy and may respond favorably to bortezomib, a decision-making algorithm based on the results of molecular diagnostic testing is provided.
