CD44 and cancer: HIF-1 was up-regulated in MDA-MB-231 cells (Additional files 4, 6) after treatment with iron chelators, sustaining EMT and hypoxia programs; mesenchymal marker genes, NDRG1 and vimentin, increased in parallel with the decrease in E-cadherin expression and the increase in CD44 and CD166 expression, which are well-known cancer stem cell markers [75] (Additional files 4, 6).