Multiple myeloma: a model for scientific and clinical progress.

Multiple myeloma (MM) is a unique cancer paradigm for investigating the mechanisms involved in the transition from a premalignant condition (monoclonal gammopathy of undetermined significance) into a malignant disease (MM). In the pathogenesis of myeloma, the dialogue between plasma cells and their microenvironment is as important as the genotypic characteristics of the tumor clone. MM is genetically highly complex, with almost all patients displaying cytogenetic abnormalities and frequent intraclonal heterogeneity that play a critical role in the outcome of the disease. In fact, it is likely that myeloma will soon no longer be considered as a single entity. This, along with the availability of an unexpected number of new treatment possibilities, has reinforced the need for better tools for prognosis and for monitoring treatment efficacy through minimal residual disease techniques. The outcome of MM patients has significantly improved in the last 2 decades, first through the introduction of high-dose therapy followed by autologous stem cell transplantation and, more recently, due to the use of proteasome inhibitors (bortezomib and carfilzomib) and immunomodulatory agents (thalidomide, lenalidomide, and pomalidomide). Moreover, the need to reexamine the diagnostic criteria of early MM and the possibility of early intervention opens up new therapeutic avenues. New drugs are also emerging, including second- and third-generation proteasome inhibitors and immunomodulators, monoclonal antibodies, histone deacetylase inhibitors, and kinesin spindle protein inhibitors, among others. Our goal is to find a balance among efficacy, toxicity, and cost, with the ultimate aim of achieving a cure for this disease.