MEIS2 and plasma cell leukemia: Analysis of microarray public data of MM patients (datasets GSE47552, GSE2113 available at http://www.ncbi.nlm.nih.gov/geo/) did not indicate significant differences of MEIS2 expression among normal PCs, MGUS, Smoldering, MM and plasma cell leukemia (PCL) cells, (shown in Supplementary Fig. 2A, B), suggesting that expression levels of this transcription factor do not correlate with a particular evolving step of these monoclonal gammopathies.