SALL4 and cancer: The mechanism of chemo-resistance is very complex, but the overexpression of some ATP-binding cassette (ABC) transporters and cancer stem cells, are two main causes of chemo-resistance [5–8].Interestingly, recent studies have shown that sal-like 4 (SALL4) gene, a member of the mammal homologs of Drosophila homeotic gene spalt, is shared by stem cells with tumor cells promoting their proliferation and conferring drug resistance on them.