HMGA2 and cancer: LIN-28, a developmentally regulated RNA binding protein which is expressed at high levels in undifferentiated ES cells, has been shown to inhibit let-7 microRNA biogenesis (Thornton and Gregory, 2012).The balance between LIN-28 and let-7 affects the expression of Hmga2 and therefore is important for ES cell self-renewal and differentiation (Li et al., 2012; Copley et al., 2013) and maintenance of an undifferentiated state in cancer cells (Shell et al., 2007).