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). The gene discussed is SOX2; the disease is cancer.