let-7 suppresses the expression of OCT4 and SOX2.It reprogrammes CSCs to differentiate via let-7/LIN28feedback loop and its overexpression regulates thestemness by increasing differentiation and decreasingself-renewal in both of the normal and cancer stemcells (26) Reduced level of let-7 is required for self-renewal and maintenance of the undifferentiated state ofembryonic and adult stem cells and its overexpression hasopposing effects, reducing their proliferation and leadingto their differentiation (39). This evidence concerns the gene POU5F1 and cancer.