A number of the NMF signatures represented subtypes of myeloma that have previously been reported; for example, we found a signature of proliferation similar to that reported by Zhan et al.41 and Broyl et al.42, a CCND1-related signature which is differentially active in samples with t(11;14) (Fig. 3b), and a signature composed of MAFB, CCND2, and ITGB7, which is active in samples with t(14;20). This evidence concerns the gene ITGB7 and plasma cell myeloma.