Perhaps the most striking evidence that BM MSCs may play an important role in the induction of MDS or leukemia comes from a study in mice, where selective deletion in osteoprogenitors of Dicer1, a RNaseIII endonuclease, essential for miRNA biogenesis and RNA processing, resulted in development of myelodysplasia and secondary leukemia [58]. This evidence concerns the gene DROSHA and leukemia.