Wellbrock et al. [8], in their work on the Hedgehog (Hh) pathway, observed the expression of the Smoothened (SMO) and Patched-1 (PTCH1) receptors, as well as their downstream mediators, GLI1, GLI2, and GLI3, but did not detect any expression of Hedgehog ligands in AML cells. This evidence concerns the gene GLI2 and acute myeloid leukemia.