Similar observations have been made by other authors, reporting an increased expression of Sonic Hedgehog (SHH), SMO, and GLI1 in BM stromal cells of MDS patients, compared to healthy donors that are known to express Indian Hedgehog (IHH) and SMO [53], with even higher HH effector levels in post-MDS AML [54]. Here, IHH is linked to myelodysplastic syndrome.