FZD4 and chronic myelogenous leukemia, BCR-ABL1 positive: In normal bone marrow (NBM) CD34+ cells, all FZD genes were detectable, but the expression level were variable between genes, with relatively highest expression level of FZD6 and FZD7. More importantly, two FZD genes, FZD4 and FZD7 were differentially expressed in CML CD34+ cells compared to NBM CD34+ cells, while FZD7 showed the highest elevation (Figure 2A).