JUN and cancer: miR-203 is widely recognised as an inhibitor of proliferation in various cancer lines by repressing various target genes.27, 30, 42, 43, 44, 45, 46 We found here that miR-203 can also inhibit myoblast proliferation by repressing c-JUN expression, an established target of miR-203 in human basal cell carcinoma.35 In addition, p63, another target of miR-203 in skin differentiation and in RMS cells,28, 29, 30, 47 was inhibited in miR-203-overexpressed myoblasts (Supplementary File 9).