In light of these findings, a later study by the researchers revealed that mostly Ihh and its downstream effectors (GLI1 and GLI2) were active in several human acute myeloid leukemia (AML) cells, including primary CD34+ leukemic cells and cytokine-responsive CD34+ Kasumi-1, Kasumi-3, and TF-1 cell lines. Here, CD34 is linked to acute myeloid leukemia.