The Let-7 human miRNA family is composed by 14 members widely considered as tumor suppressors.Let-7 miRNAs regulate, among others, the expression of the oncogenes Ras[35], Myc[36, 37] and HMGA2[38];accordingly, we found that, in FHC-silenced K562 cells, the up-regulation of Let7-g,-f and-i, is accompaniedby an important reduction of Myc expression. The gene discussed is MYC; the disease is neoplasm.