As compared to normal CD138+ cells,PCs from MM and PCL patients showed higher expression of DNMT3A (Fig. 1A), and, at a lesser extent, of DNMT3B mRNAs (Fig. 1B), suggesting a potential role of de novo DNMTs in malignanttransformation; conversely, DNMT1 levels were lower in cancer cells compared to normal PCs (Supplemental Fig. 1). This evidence concerns the gene DNMT1 and plasma cell leukemia.