Near-tetraploidy clone can evolve from a hyperdiploidy clone and cause resistance to lenalidomide and bortezomib in a multiple myeloma patient

Aneuploidy is a very common prognostic factor in multiple myeloma (MM). Nonhyperdiploidy including near-tetraploidy (NT) is a poor prognostic indicator, compared to hyperdiploidy in multiple myeloma (MM). NT results from endoduplication of hypodiploidy. We report of a 55-year-old female patient diagnosed with advanced stage MM with hyperdiploidy and t(8;14)(q24;q32). The patient responded well to lenalidomide and dexamethasone for approximately 1 year. At the time of progression, she had become unresponsive to lenalidomide and subsequently bortezomib, and was found to have NT and loss of choromosome13. There is another reported patient who had a possible interchange from nonhyperdiploidy to hyperdiploidy status, however, artifact could not be ruled out. To our knowledge, this is the first patient in whom evolution of an abnormal clone from a hyperdiploidy to a NT abnormal clone has been confirmed during the natural course of MM. This evolution is associated with resistance to novel drugs and poor prognosis in MM.